GENERAL RADIO COMPANY 1391-B Operating Instructions Manual

OPERATING INSTRUCTIONS

PULSE,

ME-

DELAY

SWEEP,

GENERATOR

Form

9374

May,

1960

AND

GENERAL RADIO COMPANY

WEST CONCORD, MASSACHUSETTS, USA

TABLE OF VOLTAGES AND RESISTANCES

TUBE VOLTS RES TUBE VOLTS RES

V502

V503

(6AV5GA)

V504

(6AV5GA)

V505

(6AV5GA)

V506

(6AV5GA)

V507

(6550)

V508

(6550)

L

1

7
8

1

3
5
8

1

3
5
8

1

3
5
8

1

3

5
8
3
4
5
8
3
4
5
8

DC DC

6

-

24

-23
40
55

145
120

55
5 5

105
120

-195

-195

-175

-90

-235

-195

-155

-75
0

2 6

-175

-155

-26
2 6

-155

-155

210k
330k
180k

7 50
600

6.8k

180k

7 50
600

6.8k

620k

51

8 40

5k

620k

51

8 40

5k
150
2 5k
8 90
600
150
2 5k
8 90
600

V510

(OA2)

V511

(12BH7)

.-,

V601

(6AS7G)

V602

(6AK5)

V603

(OD3)

7
8

1

4
5
7

1

2
3

6
7
8

1

2
3

4

5

6

1

2
5
6
7
2
5

-230

-315

-315

-

170

-340

-190

-340
145

-13

-7

145

-13

-7
225
455
300
225
455
300
145
145
225
2 50
145

0

145

(Cont.)

620k POWER 1-2

620k
280k
135k

1

5

11.9k
51

11.9k

100

1.lM
25k

0.

1.1M
25k

180k

450

0

180k

450

0
43k
15k

180k

5.lk
15k

0

15k

-

PLlOl

-

.-

T201

-

12- 23

9-13
25-26
32-33
10-11

7-8

6-16

27

-

17-18

3
4
5

6

7
8
9

10

11

12
3-5

2- 6
1-7

28

AC VOLTS

-

11

5

115

6.7

6.7

6.8

6.7

6.7
7 0

140
140
100
300

75
75

-150

-150

RES TO

GND

-

00

W

'

50k

'50k

50
50
50

50
s10k
>10k

5
5

5

CHANGE NOTICE

Operating Instructions for the

Type 1391

Please make the following corrections in your manual:

October, 1960 Printed in USA

-B Pulse, Sweep, and Time-Delay Generator

page 2, paragraph 1.2.4, line 2: Delete "(30, Figure 1.1)"
page 2, paragraph 1.2.4, line 4: Delete "(31)."
page 10, paragraph 2.6j, line 2: change "SWEEP POS" to

read "SWEEP NEG."

pages 28, 29: Substitute new Table of Voltages and

Resistances.

pages 32 et seq: Note the

All Type COC-63 capacitors are changed to
Type COC-62.

GENERAL RADIO COMPANY

West Concord, Massachusetts

for

(Form 937-D)

following.Parts List changes:

TABLE OF CONTENTS

Section 1 INTRODUCTION

1.1 Purpose

1.2 Description

Section 2 OPERATING PROCEDURE

2.1 General

2.2 Auxiliary Equipment

Initial

2.3

2.4 Synchronization Procedure

2.5 Delay Circuit

2.6 Sweep Circuit

2.7 Pulse-Generating Circuit

2.8 Use of the Pulse Source Driving Function Switch

Section 3 CALIBRATION PROCEDURE

3.1 Introduction

3.2 Test Equipment

3.3 Calibration and

3.4 Delay Circuits
Sweep- and Pulse-Timing Adiustments

3.5

Power-Supply Adjustments

3.6

Section 4 DETAILED CIRCUIT DESCRIPTIONS

4.1 General
Input Circuits

4.2
Delay Circuits

4.3

4.4 Coincidence Circuits

4.5 Sweep Circuits
Pul.se.Timing Circuits

4.6
Pulse-Generating Circuits

4.7

4.8 Power Supplies

Section 5 SERVICE AND MAINTENANCE

5.1 General

5.2 Service

5.3 Special Techniques for Trouble-Shooting Delay. Sweep. and Pulse-Timing Circuits

5.4 Setup Procedure for the Pulse Duration and Position Dial Assembly

5.5 Trouble-Shooting Chart

5.6 Trouble-Shooting Procedure

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...................................

.....................................

Control Settings

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................................

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................................

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...................

..........................

..................................

Adiustment of Input Circuits

.....................

..................................

........................

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......................

...................................

..................................

...............................

..................................

...............................

.............................

..................................

.........................

...........

...............................

............................

10
11
11

12
12
12
12
13
14
15

16
16
16
16
17
18
19
19

20
21

21
21

....

22
23
23
26

1
1
1

7
7
7
7
9
9

PARTS

LISTSAND WIRING DIAGRAMS

..........................

31

TYPE

1391-5

PULSE,

1.1

PURPOSE.

lay Generator (Figure 1.1)
designed to generate (1) push-pull pulses, of durations from 0.025

psec to

sweep voltages of durations from 3
delays from
ger pulses, which can be used independently or to delay the ini-

tiation time of the sweep and main pulse relative to the input

driving signal.

psec rise time) are compatible with most present-day oscillo­scopes. The internal sweep circuit makes possible the use

No.

-

4 RANGE

5

6 COINCIDENCE Continuous rotary control Selects threshold at which coincidence driving signals will

8

9 Sweep Duration 3-pos selector switch multiples of

10 VERNIER Continuous rotary control Adjusts sweep duration by

11

12 PULSE DURATION 4-in. rotary control and dial Sets pulse duration.

13 PULSE AMPLITUDE 10-position selector switch Sets pulse amplitude.
14 OUTPUT IMPEDANCE 5-pos selector switch

15 PULSE START 3-pos selector switch Routes internally produced or externally applied triggering

16 RESET SWEEP AND 2-pos spring-return Provides artificial reset pulse to restore sweep and delay

1.1

1

TRIGGER SELECTOR 4-pos selector switch

2 TRIGGERING LEVEL Concentric rotary control Sets dc level at which input circuits trigger.

TIME DELAY

3 MICROSECONDS Continuous rotary control Determines interval between delayed and direct synchronizing

COINCIDENCE GATE Continuous rotary control Determines duration of coincidence gate from 3 to 1000

SENSITIVITY produce delayed sync signals.

7

SWEEP TRIGGER 2-pos toggle switch Selects either direct or delayed sync signal to start sweep.
PULSE AND SWEEP

SWEEP MULTIPLIER 5-pos selector switch

PULSE DELAY

STOP TRIGGERS

The Type 1391-B Pulse, Sweep, and Time-De-

sec and at repetition rates up to 250 kc; (2) linear

1

psec to

Transition times of the output pulses (0.015

Name

-

DURATION psec.

TIMING

Selector

DELAY toggle switch circuit action.

SWEEP, AND TIME-DELAY GENERATOR

Section

is

a versatile laboratory instrument

psec to 0.12 sec; (3) time

1.1

sec; and (4) direct and delayed trig-

Type

6-pos selector switch pulses over the range from

6-in. rotary control and dial Sets duration of pulse.

1

INTRODUCTION

of an inexpensive oscilloscope by direct connection to the de­flection plates.

1.2

DESCRIPTION.

1.2.1 GENERAL. The Type 1391-B

rack or bench mounting, and
unit shown in Figure
ating controls at the front panel. Below this unit
supply, with the main POWER switch and pilot light.

1.2.2 CONTROLS. The following table lists the controls on the
front panel of the Type 1391-B Pulse, Sweep, and Time-Delay
Generator (index numbers refer to Figure 1.1):

Selects direction of input-signal zero-crossing to produce
rect synchronizing signal, and provides for ac or dc coupling
of input signal.

Determine sweep duration from

Selects any one of five load resistances for pulse current
source.

signals to determine pulse duration.

1.1

3,

6, and 12 psec.

is

available in either relay-

is

housed in two units. The upper

is

the generator itself, with all oper-

Function

-

1

psec to

*lo%

1.1

sec.

3

to 120,000 psec in decimal

from nominal value.

is

the power

..

di-

DEFINITIONS:

lows: DRIVES are input signals used to synchronize the genera­tor with external sources. SYNCHRONIZING signals are output
signals from the generator, used to synchronize the external sys- tings are called DELAYED. Timing signals occurring after start
tem to the generator. TRIGGERS are signals circulating within
the instrument to synchronize the various internal

is

generally the main output pulse; other rectangular waves gen-

Terms used in this manual are defined as fol- erated within instrument are called gates to distinguish them

from the main pulse. Timing signals produced by the delay cir-

circuits.PULSE

cuit and occurring at

of sweep by a time indicated by PULSE DELAY setting are called
START signals, while those occurring after START by a time indi­cated by the PULSE DURATION setting are called STOP signals.

a

time indicated by the delay control set-

GENERAL RADIO COMPANY

1.2.3 TERMINALS. The following terminals are on the front panel of the Type 1391-B Pulse, Sweep, and Time-Delay Generator

(index numbers refer to Figure 1.1):
No.

-

17 PRF DRIVE
18 DIRECT SYNC OUT

COINCIDENCE DRIVE

19
20 NEG
21 DELAYED SYNC OUT

PULSE

22 POS

23 NEG

24 D-C

GATE

25 NEG

26 POS

SWEEP
27 NEG
28 POS

29 START
30 STOP

POS

Name

-

Type

Binding post pair
Binding post pair

Binding post pair
Binding post pair
Binding post pair

Binding post pair and
coaxial connector

Binding post pair and
coaxial connector

Binding post pair

Binding post pair
Binding post pair

Binding post pair
Binding post pair

Binding post pair
Binding post pair

Function

To external prf-determining signal source.
To external device to be synchronized by direct pulse.

Positive or negative pulses to coincidence circuits.

To external device to be synchronized after delay interval.

Positive pulse output.

Negative pulse output.

Upon removal of link, permits insertion of d-c voltage to adjust
pulse d-c component.

Output of pulses occurring simultaneously with sweep.

Output of sawtooth signals of duration determined by SWEEP
controls.

Terminals at which are available internally generated pulse­timing triggers or to which are applied external triggers to
time pulse, depending on setting of PULSE START STOP

TRIGGERS switch.

%

1.2.4 INDICATOR LAMPS. Also on the front panel are the DE­LAY MONITOR lamp (30, Figure
ence of delayed synchronizing pulses at the DELAYED SYNC

OUT terminals, and the SWEEP MONITOR lamp
dicates the presence of the sweep signal at the SWEEP output
terminals.

1.2.5 BASIC CIRCUITS.

1.2.5.1 Input Circuits. The input circuits produce direct trig-

ger signals and direct synchronizing signals from an input drive

signal. By means of the TRIGGER SELECTOR switch, either a
positive- or negative-going zero crossing of the input signal can
be selected to produce the direct trigger and the accompanying
direct synchronizing signal, available at the DIRECTSYNC OUT
terminals. This switch also provides for ac or dc connection of
the input signal to the trigger circuits.

1.2.5.2 Delay Circuits. The delay circuits produce delayed

triggers and delayed synchronizing signals whose
rence relative to the direct trigger
MICROSECONDS and RANGE controls over a total range of
psec to
monostable coincidence-gate circuit and a gating amplifier of

adjustable sensitivity,

with the COINCIDENCE GATE DURATION and COINCIDENCE
SENSITIVITY controls at NORMAL settings). When the coin­cidence system

1.1

seconds. The coincidence system, consisting of a

is

is

used, two inputs are required to produce the

1.1), which indicates the pres-

(311, which in-

timeof occur

is

controlled by the DELAY

not used in "normal" operation (i.e.,

delayed synchronizing signal. The first operates the delay cir­cuits through the input circuit PRF DRIVE terminals to open
coincidence gate; the second, a brief pulse fed into the COIN­CIDENCE DRIVE terminals, will cause the formation of the de­layed trigger and synchronizing signal only when the gate is

open.

1.2.5.3 Sweep Circuit. The sweep circuits are started by either
the direct or the delayed trigger, depending on the position of
the SWEEP TRIGGER switch. These circuits produce (1) a lin-

early rising waveform that attains an amplitude of 135 volts in
3,

6,

or 12 psec or decimal multiples thereof up to a maximum
time of 120,000
tion as the sweep. There are three controls for the sweep cir
cuit: the 3, 6, or

VERNIER, affording about
duration. Outputs from the sweep circuits are SWEEP, positive
and negative, and GATE, positive and negative.

1

1.2.5.4 Pulse-Timing Circuits. These circuits are adjusted
the PULSE DURATION and PULSE DELAY controls, which de­termine the formation times of the START and STOP triggers
relative to the sweep. These triggers are used to start and stop

the main pulse.

The pulses produced in the timing circuits are connected

through the PULSE START STOP TRIGGERS switch to the

psec, and (2) a gate signal with the same dura-

12-psec switch, a SWEEP MULTIPLIER, and a

*lo-percent variation of the sweep

the

by

TYPE

PRF

DRIVE

COINC.

DRIVE

0

START

0

STOP

0

7-

DIRTRIG.

SWEEP TRIG.

JL

Figure 1.2. System

DELAY CIRCUITS

-

-

- -

- -

I

L

--------------

- - - - - - - - - -

SWEEP

CIRCUITS

1391-9

I

Block

PULSE, SWEEP, AND TIME-DELAY GENERATOR

=

%DIRECT

DEL.TRIG.

-

OINCIDENCE

SYSTEM

---A

Diagram.

-

1

1

SYNC

I

DELAYED

I;

:

0

SYNC

I

NEG.

NEG. GATE

POS. PULSE
NEG. PULSE

SWEEP

pulse-generating circuits. This switch, shown schematically in

Figure 1.2, will:

a. when in the INTERNAL (NORMAL) position, start and
stop the pulse at the time set on the DURATION and DELAY
controls. (In this position, marker pulses corresponding to start
and stop times are fed to the START and STOP terminals.)

b. when in the EXTERNAL position, provide for externally
generated pulses to start and stop the pulse.

c. when in the INTERNAL

+

EXTERNAL position, permits
the internally produced start and stop triggers to be added to ex­ternally generated pulses to start and stop the pulse. Thus the

delay circuits and the pulse trigger circuits can be used simul­taneously to produce a double pulse.

1.2.5.5 Pulse Source Circuits. These circuits form a bistable
system that responds to start and stop triggers generated either
internally or externally to produce the push-pull pulse of

adjust-

able amplitude, with an adjustable output impedance.

1.2.6 GENERAL CIRCUIT DESCRIPTIONS.

1.2.6.1 Input Circuits. (See Figures 1.3 a, b.) The input
cuits consist of an input amplifier, Schmitt circuit, pulse-form-

.

*

cir-

ing circuit, amplifier, and output cathode follower. The Schmitt
circuit

is

driven by the direct-coupled amplifier, and in turn
drives the direct-trigger pulse-forming circuit to produce the
direct triggers at ptf's to 500 kc. This direct trigger
nizes the remainder of the circuit erouDs within the instrument.

-

8

synchro-

It can be formed on whichever zero-crossing the user selects.
For sine- and square-wave inputs, the trigger-generating system
requires about 0.3 volt peak; for brief pulses of either polarity,
about

1

volt.

The sweep and delay circuits can be started simultaneous­ly by the direct trigger, or the sweep circuit can be triggered by
the delayed trigger. These two modes of operation, selected by
the SWEEP TRIGGER switch, either make the delay and sweep
circuits completely independent or make use of the delay

cir

cuit to delay the sweep with respect to the direct trigger.

The direct synchronizing signal

is

a 100-volt, I-psec posi-

tive pulse fed from a cathode follower to the DIRECT SYNC

OUT binding posts on the front panel. Lagging slightly behind

the direct trigger, it can be used to synchronize auxiliary equip­ment such as oscilloscopes and counters. It can also be used to
initiate the main pulse when the pulse duration

is

to be deter

mined by the delay circuit (refer to paragraph 2.8.2).

When the generator is driven by a brief, rapidly rising in­put pulse, there
and the direct synchronizing signal. This time delay permits

is

a time delay of 0.4 psec between this pulse

(1)

Figure 1.3a.

Block Diograrn

of Input Circuits.

DIRECT TRIGGER

DIRECT

SYNC

PRF.

DRIVE

-

-

LIMITER

I

TD

7

n

POS. GOING DELAY

CIRCUIT FORMING

o

-

GOING

Y

PULSE

+

-DELAY

DIRECT TRIGGER TO

0.2115

-

-

-

-

DIRECT

Figure 1.3b.

Time Relatian-

ships

in

DIRECT

SYNC

AMP.& C.F.

*kyNc

4

SWEEP

TRIGGER=

SWbTL4

\

DELAYED TRIGGER

--

Input Circuits.

CIRCUIT

0

DELAYED

TO SWEEP

CIRCUIT

DELAY

0

UT

GENERAL RADIO COMPANY

DEL. RANGE DEL. CONTROL

DIRECT
TRIGGER DELAY DELAY

FROM

INPUT

'

SYNC GATE
CIRCUITS STOP

STAR?

CONTROL

BISTABLE

-+

COINCIDENCE

GATE DURATION SENSITIVITY

I

SWEEP AMPLITUDE

GENERATOR

COINCIDENCE

4

3-1000pSEC COINCIDENCE DEL.SYNC
MONOSTABLE-

GATE

COINC.

0

DRIVE

the establishment of an accurately predetermined minimum delay,

and (2) the observation of the direct synchronizing signal on al­most any oscilloscope triggered by the input signal.

1.2.6.2 Delay Circuits. (See Figure

starts the delay circuit by opening the bistable gate. The open­ing of the gate starts a sweep generator, which produces a rising
voltage whose slope
the DELAY RANGE control. The DELAY MICROSECONDS con­trol, a. 10-turn potentiometer, provides a voltage reference
amplitude comparator. When the sweep voltage reaches the level

set by the delay control, the amplitude comparator operates a
reset trigger generator that closes the bistable gate.

The dial for the 10-turn potentiometer

ly in

1000 divisions so that the delay can be read with high in­cremental resolution. Delay
with the basic range from

range switch selects R-C time constants in the sweep generator
to produce multipliers from

1.2.6.3 Coincidence System. A monostable coincidence gate,

adjustable from about
cuit. The reset trigger produced by the main delay circuit opens

1

this gate
incidence gate permits time-selection operations. (See Figures

1.4b, c, and d.)

produces the delayed synchronizing signal (Figure

ever, with reduced sensitivity of the coincidence amplifier, the
circuit can no longer be operated by the opening of the

.dence gate alone, and the circuits are prepared for coincidence

operation. In this condition, during the intervals in which the

gate

appropriate COINCIDENCE DRIVE terminals will cause the co-

incidence amplifier to operate, resulting in the formation of the

psec to

In normal operation, the opening of the coincidence gate

is

open, the injection of a positive or negative pulse at the

POS,

4

is

determined by an r-c circuit selected by

INVERTER

::?ti

1-

Figure 1.4a.

1.4a.) The direct trigger

is

is

direct-reading in microseconds,

1

to

11

microseconds. A six-decade

1

to

lo5.

3

to 1000 psec, is a part of the delay cir-

1.1

second after the direct trigger. The co-

AMPLIFIER

I

Block Diagram of Delay Circuits.

foran

calibrated linear-

1.4b). How-

coinci-

MICROSECONDS

I

I

COMPARATOR

DELAY RESET TRIGGER

DELAY ED TRIGGER TO SWEEP

RESET

TRIGGER

AMPLIFIER

-

C

?-

L

TRIGGER

JL

delayed synchronizing
incidence gate
and triggers will be produced as there are driving pulses to the
coincidence circuit (Figure

Multiple delayed synchronizing pulses can be produced by
means of the delay and coincidence circuits, as shown in Fig­ure

1.4d. The delay circuit can divide the input prf by any num­ber up to about 20, depending on the setting of the delay time
controls. Direct synchronizing pulses are fed to the
CIDENCE DRIVE terminal. Any direct synchronizing pulse that
exists while the coincidence gate
synchronizing pulse to be generated.

1.2.6.4 Sweep Circuit. The sweep circuit (Figure 1.5a), similar
in form to the main delay
sweep generator and amplitude comparator, and a reset trigger
amplifier, which produces the reset signal to close the gate. In
this system, however, the sweep generator
cuit. It consists of a
off by the sweep gate to start the sweep, a cathode follower
with a gain of nearly unity, a feedback diode, and a gated clamp
circuit to control the initial sweep voltage. The linearly rising
voltage waveform in this circuit
comparator
reaches a preset 135 volts to form the reset trigger. In addition,
the positive sweep voltage
(2) to a cathode follower to provide positive sweep, and
through an inverter-cathode-follower to produce the negative

sweep. The bistable sweep gate drives
ing a push-pull waveform at the gate outputterminals. The nega­tive sweep at the output terminal drives a stage operating a

neon indicator lamp to show that the sweep circuits are oper-

ating.

"

AMP.

is

open, as many delayed synchronizing signals

kircuit, which switches when the sweep voltage

,

B

C.F.

PANEL

signal and delayed trigger. While the co-

1.4~).

is

open will cause a delayed

circuit,consists of a bistable gate, a

is

a "bootstrap* cir-

pentode switching tube, which

is

fed to the sweep-amplitude-

is

fed (1) to the pulse-timingcircuit,

a

phase-splitter, produc-

POS

is

COIN-

turned

(3)

TYPE 1391-B PULSE, SWEEP, AND TIME-DELAY GENERATOR

Figure

1.4b.

Delay-Circuit Timing, Coincidence

Circuit Set for Normal Operation.

DIRECT

t

SYNC.

&+

hhhh.~hLLLhhLh~

i

+l

DELAYED

,I

i

1-

h

DELAY RESET

TRIGGER

COINCIDENCE

GATE

DELAYED

SYNC

I I

VL

3MSEC. I

-T~

I

I

+

;

4

I

I

I

I

I

I

I

I

I

I

I

Timing of Multiple Pulses.

Y

1

I

Figure 1.4~.

Figure 1.4d. Time Rela­tionships When
cuit Is Used as a

Delay Cir-

PRF

Di­vider. Coincidence Circuit
Driven by Direct Synchro-

nizing Pulse.

FROM

SWEEP

TRIGGER

SWITCH

Figure 1.5a.

Block Diagram

of Sweep Circuits.

DIRECT(F~)-T~~

SYNC

DELAY

GATE.

COINC. GATE

-

.

4

-9.2~~-

;

,

,

'

I

-I

h

I

,

.

,

2

;I,

i

h

h

h

h

h

h

h

I

I I

I I

I

,I

I

;

I

~~3~p~f.~

8

I

I

I I

TIMINO CIRCUITS

h

I

I
I

I

i

POS.

GATE

NEG.

GATE

s'w"E;p

NEG

SWEEP

L

INDICATOR

DIRECT

OR

DELAYED

TRIGGER

I

I

I35v

(NORMAL)

SWEEP AMPLITUDE

COMPARATOR

Figure 1.5b.

Time Relationships

in the Sweep Circuit.

GENERAL

1.2.6.5 Pulse-Timing Circuits. The sweep voltage operates two

amplitude comparators (Figure
lower voltage level produces the start trigger (Figure
while that at the higher voltage produces the stop trigger. The d-c
control voltages for these comparators are set by the concentric
panel controls for pulse duration and pulse delay (Figure
The triggers produced by the changes of state of the comparator
circuits are differentiated and fed through a pair of cathode fol-

lowers to the PULSE START STOP TRIGGERS switch, where

they are fed to the pulse generator circuit to time the pulse and

to the START and STOP panel terminals. When the PULSE
START STOP TRIGGERS switch

CUITS (NORMAL), these triggers operate

stages,

which shape them to drive the bistable multivibrator

circuit of the pulse source.

1.2.6.6 Main Pulse-Generating Circuits. (See Figure 1.6a.) The

START and STOP triggers

circuit. This circuit drives a pair of amplifiers, which in turn

operate a pair of drivers for the output stage. The push-pull out-

put stage

is

a

pair of beam tubes used as a current source with

switched load resistors, across which the pulse of voltage

1.6a). The comparator at the

1.6b),

1.7).

is

set to INTERNAL CIR-

a

pair of amplifier

operare a high-speed, bistable gate

is

RADIO COMPANY

Figure 1.7. Close-up of Pul se-Delay and Duration Dials.

SWEEP

FR

V307

DIRECT OR DELAYED

POS.

SWEEP

DURATION

Figure 1.60. Block Diagram

of

Pulse-Timing and Output Circuits.

t

D.C.

Figure 1.6b.

Pulse Timing Diagram.

TYPE

1391-9

PULSE, SWEEP, ANQ TIME-DELAY GENERATOR

developed. The conducting output tube produces a current of

150 ma. Screen voltage on this stage

amplitude.

The output system is balanced, and the push-pull pulses link
appear at coaxial connectors and parallel binding posts. The
low-potential side of the load resistors is connected to an

is

varied to control pulse

ad-

Section

OPERATING PROCEDURE

2.1

GENERAL. The Type 1391-B Pulse, Sweep, and Time-

Delay Generator can, for instructional purposes, be considered

four separate instruments. If a thorough familiarity with all con­trols is neither desired or needed, study merely those paragraphs

that apply to the circuits being used, as listed below:

2.2

Auxiliary Equipment

2.3

Initial Control Settings

2.4

Synchronization

2.5

Delay Circuit

2.5.1

Normal Use

2.5.2

Time Selection

Sweep Circuit and Pulse Duration-Delay System

2.6

2.7

Pulse-Generatingcircuit

2.8

Use of the PULSE START STOP TRIGGERS
switch

2.2

AUXILIARY EQUIPMENT. A few auxiliary instruments
are usually needed as components of the external system.
First, a source of a timing waveform
repetition rate of the pulser. This can be a simple audio-ultra­sonic oscillator, such as the General Radio Type 1210-C

R-C Oscillator, Type 1301-A Low-Distortion Oscillator, Type

1302 Oscillator, or Type 1304-B Beat-Frequency Oscillator, or
it can be a crystal oscillator with frequency dividers to produce
any frequency
of time-coherent pulses are needed for the time-selection opera-

tions describedin paragraph 2.5.2. For these operations a timing
generator such as the Tektronix Type
equivalent can be used.

oscilloscope with broadband video amplifier is, of course, neces-

sary to permit observation of short-duration pulses. In order to
view the output pulse without degradation of rise time or shape,
the pulse must be amplified with a bandwidth in excess of 20
Mc, or else the pulse must be presented by direct connection to

up

to the 100-200-kc region. More complex sources

Choice of oscilloscope will depend on the application. An

is

needed to determine the

180,

Dumont Type 300 or

unit

ditional binding post normally grounded to the panel through a

shorting link. Under these conditions the output pulses contain

an a-c component negative with respect to ground. If the shorting

is

removed, the d-c component of an external voltage (from
any low-voltage laboratory supply or battery able to furnish 150
ma) can be varied by about +25 volts.

2

the oscilloscope deflection plates. Many applications, of course,
do not require that the ultimate rise times be attained, and for
these tests less complicated oscilloscopes can be used.

The waveforms shown in this section (Figures 2.1 through

2.7) are oscillograms taken directly from the screen of a
tronix Type 55 1 oscilloscope. Throughout the following sections,
the prf set by the
od). The operator should at first keep the dial settings in the
delay and sweep circuits considerably less than this value. When
the delay or sweep-duration settings equal or exceed the period,
the oscilloscope patterns can become unstable or difficult to in-

terpret.

2.3

INITIAL CONTROL SETTINGS. Before turning the instru-

ment on, set the following controls as indicated:

Control Setting

TIME DELAY RANGE 10-100 psec
TIME DELAY MICRO- 5.00

SECONDS
COINCIDENCE GATE

DURATION
COINCIDENCE

SITIVITY
SWEEP TRIGGER DIRECT
TRIGGER SELECTOR POS GOING AC
TRIGGERING LEVEL CENTER
PULSE AMPLITUDE 10
CIUTPUT IMPEDANCE 50

PULSE DURATION
PULSE DELAY
SWEEP MULTIPLIER 10 (60-psec sweep)

timing oscillator will be 10 kc (100-psec peri-

50-psec

-

3

NORMAL

SEN- NORMAL

5.0 on center scale (50-psec pulse)

0.5 on center scale (5-psec delay)

psec

Tek-

GENERAL RADIO COMPANY

A. INPUT SIGNAL, TRIGGER

SELECTOR AT POSITIVE

FIGURE 2.1. 10-kc PRF,

B.

INPUT SIGNAL, TRIGGER

2Opsec/cm

SELECTOR AT NEGATIVE

FIGURE 2.2. 10-kc PRF 40psec DELAY 2Opsec/cm

DIRECT SYNC
DELAY SYNC,

4Opsec

POSITIVE SWEEP,

DELAY

60psec

NEGATIVE PULSES, DELAY

C. DIRECT SYNC PULSE

20,

DURATION

20

FIGURE 2.3. 100 kc PRF DELAY SET

SWEEP SET FOR 30wsec

FIGURE 2.4. DELAY SET FOR 72psec, PRF 100 kc

TRIPLE SWEEP AND PULSE BY

INTERNAL-MULTIPLE-PULSE METHOD TOPRODUCEDOUBLE PULSE

FOR 70psec

FIGURE 2.5. PULSE PAIR, PRF 10 kc, DELAY

DIRECT SYNC TO POS

A. DIRECT SYNC

B.

DELAY SYNC
C. SWEEP
D.

PULSE

COlNC DRIVE

A. DIRECT SYNC

B.

DELAYSYNC
C. SWEEP
D. PULSE

20psec

TYPE

1391-B

PULSE, SWEEP, AND TIME-DELAY GENERATOR

FIGURE

FIGURE

2.3

INITIAL CONTROL SETTINGS. (Cont)

Control Setting

SWEEP DURATION 6 60-psec sweep
pSEC

VERNIER 0
PULSE START INTERNAL (NORMAL)

STOP TRIGGERS

2.4

SY NCHRONIZATION PROCEDURE.

a. Connect an audio oscillator (output at least one volt) to

the PRF DRIVE binding posts, and set the oscillator for a fre-

quency of 10 kc.

b. Connect an oscilloscope (prepared to write at about 20

psec per division) as follows:

(1) Cbnnect the

Type 1391-B.

(2) Connect the oscilloscope external synchronizing

ger input to the Type 1391-B DIRECT SYNC OUT.

(3) Set the oscilloscope to accept a positive-going

nal synchronizing signal.

(4)

Connect the oscilloscope vertical amplifier to the Type

1391-B PRF DRIVE binding posts.

c. Turn all equipment on. After a warm-up time of about a
minute, both neon indicators on the Type
If either indicator does not light, flip the RESET switch to start

the sweep or delay circuit.

d. Adjust oscilloscope to give a stable presentation and ob-

serve the input waveform on the oscilloscope. It should appear

as shown in Figure

e. Set the TRIGGER

The oscilloscope pattern should change phase by about 180

degrees, and should appear as shown in Figure

oscilIoscope ground to the ground of the

2.1A.

SELECTOR

2.7.

MULT PULSING, EXTERNAL METHOD

I

ortrig-

exter

1391-B should glow.

switch to NEG GOING AC.

2.lb.

2.6.

A. POS SWP,
B.

NEG PULSE

10

kc

60psec, lOpsec/cm

50psec lOpsec/cm

C. START PULSE

D.

STOP PULSE

(2Opsec/cm)

A.

10

kc

CIRECT SYNC PULSE

B.

100-kc

PULSES TO POS COJNC DRIVE

C. DELAYED SYNC

D.

6-psec

SWEEP (SWEEP TRIGGER SWITCH

IN DELAYED POSITION)

f.

Connect the oscilloscope input to the Type 1371-B DI­RECT SYNC OUT terminals and observe the 75-volt,
positive synchronizing pulse. It should appear as shown in Fig­ure

2.1C or 2.2A.

2.5

DELAY CIRCUIT.

2.5.1 NORMAL USE.
a. Leave the input circuits connected as in paragraph 2.4,

with the TRIGGER SELECTOR switch set for either
negative-going triggering. Input oscillator frequency should be
set at 10 kc.

b. Move the oscilloscope vertical input to the DELAYED

SYNC OUT terminals. The positive delayed synchronizing pulse
should appear as shown in Figure

c. Move the TIME DELAY MICROSECONDS dial to 2.00 and

observe the motion of the delayed synchronizing pulse. It should
appear as in Figure
LAY RANGE switch to 1-10

d. Set the TIME DELAY RANGE switch to the
range, and increase the MICROSECONDS dial setting from 5.00
to 11.00 (fully clockwise). This produces a delay of 110

If the delay indicator lamp goes out, flip the RESET switch to

start the

only 100

the output period from the delay circuit

Figure 2.3 illustrates this principle.

2.5.2 TIME SELECTION. There are two methods of using the
delay circuits for time selection. The method described in para­graph 2.5.2.1 (Figure
source, but uses the direct sync to produce internal multiple

pulses. The second method, described in paragraph 2.5.2.2, re­quires the use of a

delay.

e. Remember that the period set by the timing oscillator was

psec. The delay circuit is now "counting downy and

f.

Return the DELAY MICROSECONDS dial to 5.00.

2.2B. Change the setting of the TIME DE-

1.4d) does not require an external timing

timingpulsegenerator.

2.2A.

psec, and again observe the pulse.

is

positive- or

10-100-psec

5kc or 200 psec.

1.5-psec

psec.

GENERAL

RADIO

COMPANY

2.5.2.1 Internal Multiple Pulse Method.
a. Connect an external audio oscillator (set for 10 kc) to

PRF DRIVE.

b. Set the TRIGGER SELECTOR switch to POS GOING

AC.

c. Set the COINCIDENCE SENSITIVITY control fully coun-

terclockwise.

d. Set the COINCIDENCE GATE DURATION control to 250.
e. Set the TIME DELAY RANGE switch to the 100

msec range.

f. Set the TIME DELAY MICROSECONDS dial to 9.20.

g. Connect the oscilloscope vertical-amplifier input to the

DELAYED SYNC OUT terminals.

h. Set the oscilloscope writing rate at 200

sion.

i.

Set the oscilloscope for internal positive sync (or exter-

nal positive sync and connect sync input to the Type 1391-B

DELAYED SYNC OUT).

j.

Connect a wire lead from the DIRECT SYNC OUT terminal

to the POS COINCIDENCE DRIVE terminal.

k. It may be necessary to advance the COINCIDENCE SEN-

SITIVITY control clockwise if the DELAY MONITOR lamp does
not come on when the SYNC and DRIVE terminals are connected.

1. The DELAY MONITOR lamp may go out when the TIME
DELAY MICROSECONDS dial
point. The delay circuit can be started by means of the RESET

switch.

m. The oscilloscope pattern should be similar to that shown
in Figure
put and delay coincidence circuit
the action
be necessary to readjust carefully the oscilloscope synchroniz­ing controls to obtain a stable pattern since the waveform
complex.

2.5.2.2 Time Selection, with an External Timing Generator.

generator (amplitude over

and for the appropriate-polarity.

generator to the appropriate COINCIDENCE DRIVE terminals.

Type 1391-B DELAYED SYNC OUT terminals.

terminals.

ity of the input pulse, and set the oscilloscope writing rate at
200

1-msec range.

control from
glows.

trol to obtain maximum amplitude from the two delayed syn-

chronizing pulses that appear.

pear when the control

2.3B. A timing diagram showing the action of the in-

is

explainedin paragraph 1.2.6.3. At this point it may

a. Connect a 1-kc

b. Set the TRIGGER SELECTOR switch to SINGLE PULSE,

c. Connect

d. Connect the oscilloscope vertical-amplifier input to the

e. Connect the oscilloscope sync input to the PRF DRIVE

f.

Set the oscilloscope synchronizing controls for the polar-

psec per division.

g. Set the TIME DELAY RANGE switch to the

h. Set the TIME DELAY MICROSECONDS dial to 5.50.

i.

Set the COINCIDENCE GATE DURATION control to 200.

j.

Increase the setting of the COINCIDENCE SENSITIVITY

its

k.

Experiment with the COINCIDENCE SENSITIVITY con-

(1000-psec) pulse output from the timing

100-psec pulse of either polarity from the timing

counterclockwise limit until the indicator lamp

is

is

moved over each 100-psec.

is

shown in Figure 1.4d, and

10 volts) to the PRF DRIVE terminals.

Note that all 100-psec pulses ap-

in the NORMAL (clockwise) position.

psec per divi-

psec-l

is

100-psec

Correct setting should
Figure

2.7C.

1.

The TIME DELAY MICROSECONDS and COINCIDENCE
GATE DURATION controls can now be varied to study the cir­cuit action. The basic principles of operation of this circuit are

presented

ized time diagram illustrating the time selection system.

k), and move the oscilloscope vertical amplifier input connec­tion to the SWEEP POS terminals.

there

to the PRF DRIVE terminals.

that there
(Figure

synchronizing signals.

2.6

100-psec time base, to the PRF DRIVE terminals.

SWEEP POS terminals.

Type 1391-B DIRECT SYNC OUT terminals. Set the oscilloscope

for a positive synchronizing signal.

LAY MONITOR and SWEEP MONITOR indicator lamps are on.
If either indicator does not glow, flip the RESET switch. If both
lamps still do not glow, recheck the control settings against

those given in paragraph 2.3.

cycle. The oscilloscope pattern should appear as shown in Fig­ure

DURATION pSEC control to 3 (with the SWEEP MULTIPLIER

switch still at 10). Then generate 3-, 6-, and
setting the SWEEP MULTIPLIER switch to

SWEEP DURATION

SWEEP DURATION

SWEEP POS, GATE POS, and GATE NEG terminals and ob-

serve the negative sweep and the positive and negative gates.

Then return the oscilloscope connection to the SWEEP POS ter-

minals.

-

sition to

sweep in time relative to
delayed trigger may be lost
psec. If it

100
daring sweep time and thereby reduce the sweep recurrence rate.

Observe this effect as directed in steps n and o.

in

paragraph 1.2.6.3, and Figure 1.4~ shows an ideal-

m. Now obtain two delayed synchronizing pulses (as in step

n. With the SWEEP TRIGGER switch at DIRECT, note that

is

one 60-psec sweep sawtooth for each 1000-psec pulse

o. Set the SWEEP TRIGGER switch to DELAYED, and note

is

a sweep for each 100-psec timing pulse selected

2.2D).

p. Repeat step 1, observing the sweep instead of the delayed

SWEEP

a. Set all controls to the positions given in paragraph 2.3.
b. Connect the prf drive oscillator, set at 10 kc to give a

c. Connect the oscilloscope vertical amplifier input to the

d. Connect the oscilloscope sync (or trigger) input to the

e. Set the oscilloscope writing rate to 20

f.

g. Note that one

2.2C.

h. Change the sweep duration to 30 by setting the SWEEP

i.

j.

k. Place the SWEEP TRIGGER switch in the DELAYED po-

1.

m. If the sweep controls are set for a duration in excess of

psec, the sweep circuit will ignore the triggers that occur

CIRCUIT

With all equipment on and warmed up, check that the DE-

Return the SWEEP MULTIPLIER switch to 10 and the

Connect the oscilloscope vertical amplifier input to the

delay the start of the sweep 50 psec.

Move the TIME DELAY MICROSECONDS dial to move the

is

lost, flip the RESET switch.

yield a pattern similar to that shown in

psec per division.

60-psec sweep

pSEC control to

pSEC switch to 6.

the direct synchronizing pulse. The

is

generated for each input

12-psec pulses by

1

and switching the

3,

6, and 12.

if

the delay setting exceeds 100

TYPE

1391-B

PULSE, SWEEP, AND TIME-DELAY GENERATOR

n. Set the SWEEP DURATION pSEC control to 12 and the
SWEEP MULTIPLIER to 10 to produce a
sweep recurrence rate is now 5 kc. If the
goes out, flip the RESET switch.

o. Reset the sweep controls
pSEC to 6, SWEEP MULTIPLIER to lo), and vary the input tim­ing frequency from 10 kc at the audio generator. Note that as
the frequency

stable. The vernier control can be set to either

restore stability.

2.7

PULSE-GENERATING CIRCUIT.

a. Set all controls to the positions listed in paragraph 2.3.

b. Connect the oscilloscope vertical amplifier input to the
PULSE POS terminals. If either brief pulses or a fast rise time

is

desired, use a coaxial cable for this connection.

c. Connect the oscilloscope ext sync to the Type 1391-B

DIRECT SYNC terminals.

d. Observe the output positive
with the DELAY and DURATION controls, setting DELAY to 20,
DURATION to 20. The negative pulse should appear as in Fig­ure

2.2D.

e. Move the oscilloscope connection to the PULSE POS ter­minals and observe the positive

f.

ing the SWEEP DURATION

pulse duration and delay and return the SWEEP DURATION

switch to

g. Reduce the pulse duration to 25 psec by resetting the

PULSE DURATION (inner) dial.

h. Reposition this

sweep by rotating the PULSE DELAY dial counterclockwise.

Note that the three rings of numbers on the PULSE DURATION

and PULSE DELAY dials correspond to the three settings of the

PULSE SCALE switch.

i. Now pulses of 2.5

MULTIPLIER switch set at
delays can be set by means of the sweep switches, PULSE DU-

RATION, and PULSE DELAY controls.

j.

Then decrease the PULSE DURATION setting until
minimum duration
duced even beyond the usual amplitude, and that the pulse polar­ity will reverse suddenly at a DURATION setting below zero.

This

is

chanical stop of sufficient accuracy to stop the motion of the
DURATION dial at exactly zero.

is

increased toward 16 kc, the sweep becomes in-

Reduce the pulse duration from 50 to 25 psec by switch-

6.

25-psec pulse to start 25 psec after the

-

Short Pulses: Decrease the sweep duration to 3 psec.

is

produced. Note that this pulse can be re-

characteristic, since it

for60 psec (SWEEP DURATION

40-psec pulse.

pSEC control to

psec can be obtained with the SWEEP

1.

Various other pulse durations and

is

not possible toproduce a me-

120-psec sweep. The

SWEEPMONITORlamp

f

or - 10% to

50-psec pulse. Experiment

3.

Observe the

pSEC

sl

pulse of

DIRECT

SYNC

DELAYED

SYNC

Figure

J

2.8.

Adding Network

20Wf

i

1-0

2?r~f

I

I

for

START

*

STOP

Multiple Pulsing.

k. Set up a I-psec pulse and experiment with the OUTPUT
IMPEDANCE and PULSE AMPLITUDE controls. Some defects
might appear in the pulse due to impedance mismatch as the

OUTPUT IMPEDANCE

PULSE AMPLITUDE control adversely affects the pulse shape
when the pulse
PLITUDE control is generally satisfactory for pulses of long

duration and over a 10- or 20-db range, but for best pulse shape
an attenuator or a pad of the

2.8

USE OF THE PULSE START STOP TRIGGERS SWITCH.

2.8.1 INTERNAL (NORMAL) POSITION.

a. Set all controls to the positions listed in paragraph 2.3.
b. Set the oscilloscope horizontal controls for a writing rate

of 20

psec per division.

c. Connect the oscilloscope vertical amplifier input to the

PULSE NEG terminals.

d. Connect the oscilloscope sync to the Type 1391-B DI-

RECT SYNC terminals.

e. Observe the

It should appear as shown in Figure

f. Now move the oscilloscope vertical input connection to

the START terminal. Note the presence of a 5-volt positive

start pulse corresponding to the leading edge of the main pulse

(Figure

g. Move the oscilloscope vertical input connection to the

STOP terminal, and note the presence of a 5-volt positive stop

pulse as shown in Figure
terminals a negative pulse at the end of the sweep. Move the
PULSE DURATION dial and note the motion of the stop pulse
corresponding to the dial reading. The start pulse moves when

the PULSE DELAY dial is moved.

2.8.2 EXTERNAL POSITION.

a. Move the oscilloscope vertical input connection back to
the PULSE POS terminal, and, if possible, set the oscilloscope
for d-c input.

b. Set the PULSE START STOP TRIGGERS switch to the

EXT position.

c. Tap first the START and then the STOP terminal with a
piece of metal held in the hand. The pulse should start
with each tap. In this manner, pulses can be produced by any ex­ternal trigger generator.

d. To use the delay circuit to time the main pulse, proceed
as directed in steps e through h below.

e. Set the oscilloscope and PULSE START STOP TRIGGERS

switch as indicated in steps a and b

Connect a jumper wire from the DIRECT SYNC OUT ter-

f.

minal to the START terminal and another from DELAYED SYNC

to STOP terminal.

g. Note that a

delay interval,
delay settings from
pulse duration

h. This connection, in which the delay circuit

trol pulse duration, permits the production of pulses up to

seconds in duration. To produce such a pulse, set (if possible)
the oscilloscope writing rate at 0.2

is

2.6C).

is

is

setting

set to greatly reduced values. The PULSE AM-

50-psec negative pulse on the oscilloscope.

50-psec pulse, corresponding to the 50-psec

produced (Figure 2.5B). Now vary the time

1

psec up to about 90 psec and note that

controlled by delay.

is

varied. Note also that the

proper impedance

2.6B.

2.6D. Note at both START and STOP

abovz.

sec per division. Disconnect

is

recommended.

andstop

is

used to con-

1.1

GENERAL RADIO COMPANY

the driving oscillator from the PRF DRIVE terminals. Set the
TIME DELAY MICROSECONDS dial to 11.00, and the TIME
DELAY RANGE switch to 100
the RESET switch or tap the PRF DRIVE terminal quickly, and

note the production of the long pulse.

2.8.3 INTERNAL

mits externally produced trigger pulses to be added to the start

and stop triggers generated in the pulse timing circuits. To test
the operation of this switch position, generate a double pulse as
follows:

a. Build and connect the adder circuit shown in Figure 2.8.

b. Set the SWEEP TRIGGER switch to DELAYED.

f

EXTERNAL POSITION. This position per-

psec

-

1

sec. Now either flip

Section

CALIBRATION PROCEDURE

3.1

INTRODUCTION.

are given in the order of signal progression through the instru-

ment. Paragraph 3.2 lists the test equipment necessary to carry

out the calibration of the various circuits, and paragraphs 3.3

through 3.6 discuss the calibration and readjustment procedures

necessary in each circuit.

It is hardly likely that a complete calibration, such as that

given every new instrument in the General Radio laboratory, will

ever be necessary. Usually few, if any, adjustments are neces-

sary when a tube or circuit component
failure. Gradual degradation in tube characteristics with use may
require retouching of the screwdriver adjustment common to all
ranges in the sweep or delay circuit. Also, some unpredictable
shift in the values of resistors or capacitors in range timing cir-

cuits will generally appear as a change in the calibration of one
range. Only the adjustment for thatrange must be set, and

relevant paragraph must be consulted, along with paragraph 3.2.

A

common adjustment is the range minimum adjustment
(R238) in the delay circuit, which may require readjustment when
V203

is

replaced. This adjustment, discussed in paragraph 3.4,

is

common to all delay ranges. An equivalent adjustment may be
necessary in the sweep circuits to restore the calibration of the
pulse-delay dial when either

trols requiring readjustment are the pulse duration and delay
minimums R412 and
justments are those used to correct for component tolerances in
the

R-C time constants. Such adjustments must

when the components themselves drift (unlikely) or are replaced.

3.2

TEST EQUIPMENT.

test equipment necessary for recalibration depend entirely on
the accuracy desired, the complexity of the recalibration, and,
to some extent, on the range being recalibrated. This equipment

can range from a cathode-ray oscilloscope, audio oscillator, and
ac-dc multirange meter to the full series of

Calibration and readjustment procedures

is

replaced because of

onlythe

V303 or V307

R411. (Refer to paragraph 3.5.2.) Other ad-

The type and quantity of auxiliary

is

replaced. The con-

be

made only

time-measuringequip-

c. Connect the oscilloscope vertical deflection input to the

PULSE POS terminals.

d. Connect the oscilloscope synchronizing terminal to the

DIRECT SYNC OUT terminals.

e. Set the PULSE START STOP TRIGGERS switch to EX-

TERNAL and move the DELAY MICROSECONDS dial from its

standard position, noting that the delay circuit controls the dura-

tion of the pulse.

f. Set the PULSE START STOP TRIGGERS switch to IN­TERNAL
dard positions. Note the presence of a double pulse. The delay
and duration of the second pulse can be varied by means of the
PULSE DELAY and DURATION controls.

f

EXTERNAL, with the pulse timing controls in stan-

3

ment listed below. The equipment listed below
complete recalibration of the instrument.

(1) Oscilloscope

lent.

(2) Crystal-controlled time-marker generator

Dumont 300, or equivalent producing time markers from

10,000

ously available at the panel terminals of the marker generator.

necessity in the recalibration of the instrument, a time-interval
meter simplifies the calibration of the longer sweeps, delay in­tervals, and pulse durations. This time-interval meter should
operate from two triggers, one to start and one to stop the

interval measurement. Ideally, it should resolve
input pulses. The time-interval meter will facilitate the measure­ment of the longer delays, sweeps, and pulses, without the ne-

delays on an oscilloscope. Possible instruments for use in this
application, if available, are the Berkeley 5571 and 5510,
lett-Packard 521-A, 522-B, or 524-B plus 526-B, or theLFE 501.

(General Radio Type 1210, 1302, or equivalent) needed to set
the prf, and an a-c vacuum-tube voltmeter to measure either the

rms or peak value of the input voltage.

3.3.1 ADJUSTMENT OF R104.

DIRECT SYNC OUT terminals.

and observe the direct synchronizing signal as the audio oscil-

lator gain-control setting

psec. All of these timing markers should be simultane-

(3) Time-interval measuring system

cessity of viewing the very slow transients arising from the long

Additional test equipment includes an audio oscillator

3.3

CALIBRATION AND ADJUSTMENT OF INPUT CIRCUITS.

a. Connect the audio oscillator (set to 10 kc, output atleast

1

volt) to the PRF DRIVE terminals.

b. Connect the oscilloscope vertical amplifier input to the

c. Center the TRIGGERING LEVEL control.
d. Set the TRIGGER SELECTOR switch to POS GOING

-

Tektronix 530 or 540 series, or equiva-

-

is

decreased.

is

adequate for

-

Tektronix 180,

1

to

While not an absolute

time-

1-

or 0.1-psec

Hew-

AC,

TYPE

1391-B

PULSE,

SWEEP,

AND TIME-DELAY GENERATOR

e. Adjust R104 so that the direct synchronizing pulse

-

is

..

formed with minimum voltage input. With correct adjustment, the

input voltage will be less than 0.3 volt rms.

3.3.2 ADJUSTMENT OF

C102.

a. Set the TRIGGER SELECTOR switch to POS GOING AC.

b.

Set the SWEEP TRIGGER switch to DIRECT.

c. Connect the oscilloscope probe to the center (output) ter-

minal of

S203, the SWEEP TRIGGER switch.

d. Adjust

C102 for a trigger amplitude of 5 to 6 volts peak-

to-peak.

3.4

DELAY

3.4.1

CIRCUITS.

ADJUSTMENT OF THE TIME DELAY MICROSECONDS
DIAL MINIMUM AND MAXIMUM. This adjustment should be ne­cessary only when

eitherV203, V204, or V205 has been replaced.

The time delay between the direct and delayed synchronizing

pulses must be measured accurately, and should be within 0.3

percent.

There are three different ways to measure the time delay
between the direct and delayed synchronizing pulse. The first
two ways require the use of only the high-speed oscillograph
and the precision time-marker generator. The third method, most
convenient for the three longer delay ranges, requires the use of
the time-interval measuring device (refer to paragraph 3.2).

3.4.1.1 First Method. In this method, the time-marker generator

is

used to set the prf of the Type 1391-B at a rate considerably
slower than the period corresponding to the delay range to be
checked. A second output from the time-marker generator

is

pre-

sented to calibrate the oscilloscope sweep. An electronic switch

that will simultaneously present the delayed synchronizing sig-

nal and the timing markers to the oscilloscope

is

recommended.
Timing markers can also be presented if they are placed on the
oscilloscope gate input terminals either to brighten or to blank
the oscilloscope sweep to display the marker interval. The posi­tion of the direct synchronizing pulse relative to the timing
markers

is

carefully determined and the oscilloscope probe

is

moved to the DELAYED SYNC terminal. The delay dial calibra­tion can then be checked at the cardinal points represented by
the timing markers. This procedure

is

the only effective means

for calibration of the lower two delay ranges, 1-10 and 10-100

psec.

3.4.1.2 Second Method. In the second method, the timing-mark­er generator

is

used to set the prf of the Type 1391-B as in the
first method, but the higher-frequency timing markers corres­ponding to the cardinal points on the delay dial are fed to the

appropriate COINCIDENCE DRIVE terminals and the coincidence
system is adjusted so that coincidence
the coincidence gate
marker pulses. Since there

is

produced at the same time as one of the

is

a finite rise time of about 0.2 psec

is

established only when

at the early edge of the coincidence gate, the correct alignment
of the early edge of this gate with a given marker pulse to light
the DELAY MONITOR lamp will permit sufficiently accurate cali-

bration only above 100

effective only on the third range and above. If, for example, it

psec, and therefore this method becomes

is

desired to calibrate the 100-psec-to-1-psec range at 100-psec
cardinal points, the timing-marker generator should set the prf at

100 cps, and

100-psec calibration markers should be fed to the
COINCIDENCE DRIVE terminal corresponding to marker polarity.
The COINCIDENCE GATE DURATION control should be set at a
value considerably less

than 100 psec, say 20. Now suppose

the TIME DELAY MICROSECONDS dial

delay

is

actual

190 psec. The second 100-psec marker pulse

is

rotated so that the

from the timing generator will lie in the center of the coincidence
gate, and the DELAY MONITOR lamp will glow. As the delay
dial setting is increased to exactly 200
of the coincidence gate will move out from under the
marker and the lamp will go out. It

is

the accurate calibration point

attained when the delay dial

psec, the leading edge

100-psec

is

apparent, therefore, that

is

moved from higher to lower delay reading at the point where the

DELAY MONITOR lamp just lights. For the calibration of longer
delay ranges, correspondingly longer time-duration

coincidence­gate settings can be used. The accuracy, determined by rise
time of the coincidence gate and the ignition voltage of the DE-

LAY MONITOR lamp, increases.

3.4.1.3 Third Method. A time-interval measuring system, capa-

ble of being operated by the direct and delayed synchronizing

signals, provides a convenient method of calibration. Suppose

the time-interval meter

is

capable of resolving and counting

1-psec pulses. The delay circuit can be calibrated to an accuracy

of 0.1 percent at

1

msec by the plus or minus one-count limita­tion. Four decade registers are necessary for this precision at
the low end of a range. The procedure

is

to connect the start
terminals of the time-interval meter to the DIRECT SYNC OUT
terminals of the Type 1391-B, and the stop terminal to the DE­LAYED SYNC OUT terminal of the Type 1391-B. A simple trig­ger, derived on the longer ranges simply by the tapping of a fin­ger against the PRF DRIVE terminal or by the use of a switch
and a battery, initiates a "single stroke" delay-circuit action
and opens and closes the timing gate of the time-interval meter

at the delay period. The delay then reads directly in the decade

registers of the interval counter.

By any one of the above three methods, the accuracy at

both ends of the TIME DELAY MICROSECONDS dial should first

be established for two or three ranges. If the minimum or maxi­mum

is

consistently off on all these ranges, then either the de-

lay minimum control

(R238) and/or the delay maximum control
(R236) should be readjusted. This readjustment should be ac­complished on the 10-100-msec range. It is necessary to set both
the minimum and the maximum controls for correct value at dial
readings of 200 for the minimum and

ing calibrated the 10-100-msec range in this manner, check

1000 for the maximum. Hav-

over

all dial linearity by checking the delay at cardinal dial points,
and test the other ranges to establish their accuracy. If only one
range deviates from the correct readings, adjust the appropriate
potentiometer
range has two adjustments: R233 adjusts the time constant

(R228 to R233). Note that the 100 msec-to-1-sec

COP

rectly to produce the accurate maximum delay at 1 sec and R232
adjusts the amplitude of the initial voltage step for the correct
dial reading at 100 msec. If V203 has been replaced, it may be
necessary to readjust C222 of the

I-10-psec range to restore

dial calibration due to small changes in stray capacitance.

3.4.2 COINCIDENCE GATE ADJUSTMENTS. If, upon replace­ment of
incidence gate duration departs intolerably far from 3 or

V206, it

is

found that either the minimum or maximum co-

1000
psec, adjust R255, the 1000-psec adjustment, or R249, the
3-psec adjustment. Usually only a cathode-ray oscillograph con­nected at

TP204

is

necessary to establish the desired measure­ment accuracy. Of course, a more precise adjustment of either
the minimum, maximum, or any point between can be made if
higher accuracy

is

desired. It

is

necessary to repeat the

3-

and

GENERAL RADIO COMPANY

TO OSCILLOSCOPE

('VERTICAL

TO

PULSE
TERMINAL

&COMMON

GROUND

Figure

3.1

Adder Circuit Diagram

then the

accurately, since there

3.5

3.5.1 GENERAL. The sweep- and pulse-timing adjustments are
discussed together here because the characteristics of the sweep
control, the accuracy of the pulse-timing scales, and the con­trols corresponding to the previously described delay minimum
and maximum controls are the calibration controls that determine
the minimum pulse delay and the maximum pulse duration and

delay.

by the time-measuring techniques described in paragraph
Here it
duration, and the easiese way to do this

tor and adder network for the oscilloscope to present the sweep

gate and pulse transitions simultaneously. The adder and its
connections are shown in Figure 3.1. Pulse duration, delay, and

sweep duration can be adjusted by observation of the pulses
produced at the beginning and end of the sweep gate and main
pulse. In order to register the marker showing the beginning of

the sweep with the timingmarkers, the sweep can be triggered
by the delay circuit and made coincident with a specific timing

marker.

3.5.2 OVER-ALL SWEEP AND PULSE-TIMING ADJUSTMENT.

The

sweep duration .and for synchronization of the readings of the
delay and duration dials. Make sure that the duration and delay
readings have a common error on several ranges before readjust­ing those calibration controls common to all ranges. An error in

pulse duration or delay appearing on only one range can be elim-

inated by adjustment of that range's sweep time constant only.
If an error in pulse duration or delay appears on all ranges, pro­ceed as follows:

terminals.

markers by means of an additional network or a dual-channel os-

cilloscope attachment.

marker output and obtain a coherent pattern on the oscilloscope.

with one

to 4.0.

500-psec mark.

1000-psec adjustments more than once to establish both

is

a slight interaction.

SWEEP-

600-psec sweep range

a. Construct the R-C network shown in Figure 3.1.
b. Connect this network to the PULSE NEG and GATE NEG

c. Mix the output from the R-C network with

d. Synchronize the Type 1391-B with the

e. Using the DELAY controls, align the start of the sweep

f.

g. Center R408 (DURATION MAX).

h. Adjust R333 (600

AND

PULSE-TIMING ADJUSTMENTS.

The sweep and pulse-timing adjustments can all be made

is

necessary to measure both sweep duration and pulse

is

to build a differentia-

is

used for the initial adjustment of

10,000-psec timing

100-psec timing pulse.

Set the PULSE DELAY to 1.0

psec) to set the end of the pulse to the

and

the PULSE DURATION

NEG.

TERMINAL

3.4.1.

100-psec timing

Adjust

i.

600

psec.

j.

the

100-psec mark, and then rotate the PULSE DURATION dial

to exactly zero, without disturbing the PULSE DELAY dial.

k.

Adjust R412 (DUR

incide with the start af the pulse at the

pulses will disappear.)

1.

the TIME DELAY MICROSECONDS dial to read 5.50.

m. Adjust R407 (POSITION MAX) to set the end of the pulse

to coincide with the start of the pulse at500 psec, (Both pulses

will disappear.)

n. If any adjustments required extensive resetting, repeat the

procedure; maximum adjustments have a second-order effect on

the minimum voltage and vice versa.

3.5.3
checked the

300-psec sweep to the 300-psec mark by adjusting R332 (300

psec). Use an oscilloscope writing rate of 50 psec per division.

1200-pSEC ADJUSTMENT. As in paragraph 3.5.3, adjust

3.5.4
R334 (1200

the twelfth

~ain sweep- and pulse-timing adjustments are now com­plete, and the tracking of the
checked by means of a marker generator or, for the longer ranges,
a time-interval counter operated by the pulse or sweep gates. A
failure on the part of either the

xlo2range within two percent indicates that the value of a

the
timing capacitor has changed, and the capacitor of the faulty
range should be padded or replaced. If all three ranges fail to
track by about the same amount, the timing capacitor of the

x102 range (C323) should be replaced or padded.

CALIBRATION OF THE 3-, 6-, AND

3.5.5

a. First make tests to establish the accuracy of pulse timing

on the

b. Set the controls as follows:

SWEEP MULTIPLIER
SWEEP DURATION MICROSECONDS
PULSE DURATION 4.00 psec (Center Scale)

c. Connect a 10-kc signal from the marker generator to the
PRF DRIVE terminals, and use
from the marker generator.

d. Center

duration of 4.00

e. Set the SWEEP DURATION to

pulse using R329 (3 psec).

f.

the half-amplitude pulse duration to

g. Set SWEEP DURATION MICROSECONDS control to 3. Set
PULSE DURATION dial to zero, and adjust C417 for
tion pulse.

If the
4-psec pulse with C321, or

R352 (SWP AMP) to set the end of the sweep to

Adjust R411 (POS MIN) to set the start of the pulse to

MINI

to set the end of the pulse to co-

100-psec mark. (Both

Now set the PULSE DURATION dial to 5.00 andadvance

300-@EC SWEEP ADJUSTMENT. Having calibrated or

600-psec range calibration, set the end of the

psec) to set the end of the sweep to coincide with

100-psec mark after the start of the sweep.

x10, x10! and x104 ranges can be

x10, x10: or x104 range to track

12-@EC RANGES.

600-psec range (refer to paragraph 3.5.2).

Set

-

1

6

1-psec oscilloscope markers

R330 (6 psec) and adjust C321 to obtain a pulse

psec at half amplitude.

3

and adjust for a 2-psec

Set the SWEEP DURATION control to 12.00 and adjust

8psec with R331 (12 psec).

zero-dura-

NOTE

6-psec sweep cannot be adjusted to produce a

if

R332 and R329 are far

TYPE

1391-B

PULSE, SWEEP, AND TIME-DELAY GENERATOR

from center, reset C321 and repeat the 6-psec adjust­ment (R330), and readjust the 3-psec and 12-psec just R612.
ranges.

V303

is

Generally, when

to restore proper operation to the 3-, 6- and

3.6

POWER-SU,PPLY ADJUSTMENTS.

3.6.1 TEST EQUIPMENT. The minimum test equipment neces-

sary for the correct adjustment of the power supply includes:

a. a 300-v battery or regulated power supply set for

b.

a 5- or 10-amp ~ariac@autotransfonner or equivalent,
c. an accurate a-c voltmeter to set line voltage,
d. a wattmeter with 500-watt scale,
e. a volt-ohmmeter with

ton 772 Analyzer or equivalent).

additional apparatus, useful though not absolutely neces-

f.

sary, includes either a wave analyzer (General Radio Type
736-A or equivalent) or a Distortion and Noise Meter (General

Radio Type 1932-A or equivalent).

3.6.2 INPUT POWER CHECK. The Type 1391-B requires 420
watts at

3.6.3 300-VOLT REGULATOR ADJUSTMENT.

115 volts, 60 cycles.

a. Measure the 300-volt power supply at pin 2 of plug

replaced, only C321 must be retouched

12-psec ranges.

300v,

20,000-ohm/volt sensitivity (Wes-

PL401

SO602 (yellow wire). It should read 300f 1 volts; if not, ad-

or

b. To check the compensation adjustment, buck most of the

300 volts out with either a 300-volt battery or a second 300-volt

regulated power supply. This will permit the voltmeter to be used
in differential connection on

volt Type 1391-B supply can be offset by either 1 or 2 volts to

permit the meter to read upscale.)

Now vary the line voltage to the Type 1391-B over the

105-125

10 percent the regulator output decreases by 0.5 to 1 volt and
vice versa. If the compensation curve
the 300-volt center, readjust R607 to make

need readjustment to maintain correct output voltage.

3.6.4 -150-VOLT ADJUSTMENT.

duce
set at 115 volts.

3.6.5 -400-VOLT ADJUSTMENT. Adjust the PULSE DURATION
and sweep timing controls to produce a 25-millisecond pulse at

a 20-cps repetition rate. Set the PULSE AMPLITUDE control to
maximum and set the output impedance for the highest-amplitude
negative pulse whose negative edge can be seen on the screen.
Set R618 for minimum line-frequency ripple on the "bottom" of.
this pulse as the line voltage

(210-250)volt range. Note that as linevoltage increqses

-150volts output at pin 6 of plug PL401, with input voltage

its

1-

or 5-volt scale. (The 3300-

is

not symmetrical about

it

so. R612 might

R618 should be set to pro-

is

varied from 105 to 125 volts.

GENERAL RADIO COMPANY

Section

DETAILED CIRCUIT DESCRIPTIONS

4.1

GENERAL.

in much the same order as that taken by a signal, beginning with
the input circuits. For convenience in maintenance, the compo­nents in each circuit group are numbered in the same series, as

shown in the following list:

Input Circuits 100's Figure 5.1
Delay Circuits 200's Figure 5.2
Sweep Circuits 300's Figure 5.3
Pulse-Timing Circuits 400's Figure 5.4
Pulse-Generating Circuits 500's Figure 5.5
Power Supply 600's Figure 5.6

4.2

INPUT CIRCUITS.

sisting of dc amplifier VlOlA and Schmitt circuit V102 produces
the brief direct trigger pulse, and maintains its slope and ampli­tude constant irrespective of the rate of change of input volt­age at the PRF DRIVE terminals. The amplifier VlOlA
nected to the PRF DRIVE binding post through blocking capa-

~lll

citor
D103. For dc operation, Clll

serves as a d-c amplifier for the Schmitt circuit,

is

in conduction, its plate current will maintain the cathode volt-

age for both sides at about

is

below 90 volts, the circuit

conduction. Now suppose the plate voltage of VlOlA

V102B begins to conduct. The decreasing plate voltage of

until
V102B reduces grid voltage on V102A and therefore reduces the
cathode voltage, making
positive feedback quickly turns
the plate voltage of
V102A is sufficiently below its cutoff voltage so that the grid
voltage

switches back to the original state. Therefore the circuit exhibits

a hysteresis effect.

VlOlA is normally set in the center of this hysteresis loop. A
positive-going voltage at the grid of

swings
ducing a positive transition at its plate. The TRIGGER SELEC­TOR switch
this wave front
trigger that momentarily switches

the center of the hysteresis loop. An adjustment of

TRIGGERING LEVEL control, can:

ative input pulse. (Note that in the optimum sensitivity adjust-

ment, the a-c component of a brief input pulse may not be ade-

quate to cause the hysteresis loop to be traversed.)

puts. (This is the normal setting.)

ofV102B must be reduced to below 90 volts before V102

The bias establishing the quiescent plate current for

V102B into its regenerative region, turning it off and pro-

R103 and R104 control the bias on

permitVl02 to switch on either a small positive or a neg-

a.

b. optimize the sensitivity of the trigger for small signal in-

The following circuit descriptions are presented

Tubes and

Circuit Components No. Schematic Diagram

(See Figure 5.1.) The trigger circuit con-

is

con-

and the symmetrical limiter circuit R101, D102, and

is

shorted out by S101. VlOlA

V102. If V102A

95 volts. If the plate voltage of VlOlA

is

stable and V102A remains in

is

increased

V102B conduct even more heavily. This

V102A off and V102B on. When

VlOlA

is

again reduced to below 95 volts,

VlOl

is

amplified and

is

shown in the positive-going position, so that

is

differentiated by C103 and R112 to a positive

V103A on.

VIOLA, establishing

R103, the

4

c. select an exact voltage at which V102 will switch, thus

permitting the exact sensing of zero crossing for large signals.

The

pentode section of V103
ger generated by the Schmitt circuit on the selected zero cros­sing, either positive- or negative-going. A network in the plate

of

V103A produces the 0.10-psec, 20-volt negative direct trig­ger. A longer-duration negative trigger of somewhat higher am­plitude, developed across
coupled through the

V103B. V103B
turned off by the negative trigger, produces a 100-volt positive
sync, about
follower capacitively coupled to the DIRECT
nals.

channel. The total delay accumulated between the PRF DRIVE

and DIRECT SYNC OUT terminals is about 0.4
lay permits the delay and sweep circuits to be precisely cali­brated at their minimum values.

4.3

4.3.1 GENERAL. For convenience, the delay circuits can be
divided into two groups; the main delay circuit, across the top
of Figure 5.2, and the coincidence circuit system, the line of

circuits at the bottom of Figure 5.2. Idealized waveforms are

shown in the time diagram accompanying the block diagram for

these circuits (Figure 1.4).

teristic. The loop action

opens a
voltage

SECONDS control, the amplitude comparator circuit switches,

generating a trigger. The trigger is amplified and resets the bi­stable gate, ending the sweep. The loop then remains quiescent

until another direct trigger
lasts from
cuits up to the amplitude comparator are direct coupled.

4.3.2 DELAY GATE. The delay gate
gate tube
the supply voltage for the gate
respect to ground; therefore the plate potential of the conducting
gate tube
The gate
circuit, and switches regeneratively to turn V201 off and V202
on. The fall in voltage at the plate of V202 turns
starts the sweep.

4.3.3 DELAY SWEEP GENERATOR.
duction, with its grid slightly positive. Plate load resistors,
ranging from 500 kilohms to five megohms, selected by the DE­LAY RANGE switch, drop almost the entire power-supply vol­tage at the plate
timing capacitor appropriate to the delay range charges through

the selected resistor. Thus the delay sweep

1

psec in duration, which

DLlOl provides a 0.2-psec time delay in the direct sync

DELAY CIRCUITS.

The main delay circuit

bistable gate and starts a sweep circuit. When the sweep

eguals the d-c voltage set by the TIME DELAY MICRO-

1

psec (minimum) to one second (maximum), the cir-

(V201)

is

negative with respect to ground by about 15 volts.

is

opened by the negative direct trigger from the input

0.2-psec delay line DLlOl to the grid of

is

normally conducting at zero bias, and, when

is

normally on, the other (V202) normally off.

ofV203 when it is on. When V203 goes off, the

is

turned on by the positive trig-

LlOl and R113,

is

fed toV104A, a cathode

is

aloop with a monostablecharac-

is

started by the direct trigger, which

is

received. Since the delay sweep

is

is

+55 volts and -150 volts with

V203 is normally in con-

is

capacitively

SYNC

OUT termi-

psec. This de-

a bistable circuit. One

V203 off and

is

a portion of the

TYPE

1391-B

PULSE, SWEEP, AND TIME-DELAY GENERATOR

exponential voltage produced by the charging of a capacitor
through its associated resistor toward the supply voltage. The
slope is correctly set for the selected range by a potentiometer,
for all ranges except one.
initial plate voltage on the

lower starting plate voltage due to the five-megohm charging re-

sistor on this range.
ginning of the
capacitance, while on the same range C222 provides an adjust-

ment to permit exact duplication of capacitance in the presence
of strays for each instrument. The rising exponential voltage pro­duced by the switching action of V203

follower
tude comparator.

4.3.4 DELAY AMPLITUDE COMPARATOR. V205
amplitude-comparison circuit. A d-c reference voltage, estab­lished by the DELAY MICROSECONDS control,
late its triggering d-c level from a minimum of about 15 volts
over a hundred-volt span. When the DELAY MICROSECONDS
control

volts before the amplitude comparator triggers; however, with
the control at maximum, the voltage must rise to over 100 volts.

The minimum and maximum voltages are set by R236 and R238

to give the correct
range. Obviously,

tage established by the DELAY MICROSECONDS control were

linear as a function of angle, the DELAY dial reading would be
linear. It is apparent that the delaying sweep is not linear, being
one third of a complete exponential change curve at its maximum
value. Due to the current drawn by V205 and R219 from the arm

of the delay potentiometer
angle

is

ing in a linear delay scale.

4.3.5 DELAY RESET TRIGGER STAGE. After
determined by the sweep and the amplitude-comparison reference
voltage, V205 triggers, the left side goes on and the right side

goes off. The regenerative rise in voltage at the right-hand plate

of V205 causes

producing a negative trigger, which is fed to the grid of
turning V202 off and terminating the sweep. This reset pulse is
also fed through
stable character of the main delay loop should now be apparent.
If, for some reason, the delay reset trigger produced by the am­plitude comparator fails to reach and reset the gate, no second
trigger can be produced by the amplitude comparator, and the

sweep voltage will rise to a maximum value set by the grid cur-

rent in

V204A. The loop will be quiescent in this "locked outn
position. The action of the circuit can then be initiated only by
artificial reset trigger injected at the grid of
by means of the RESET switch,
the bias from
the loop to its normal state. The circumstances under which the
"lock out" conditions usually occur are:

a. upon

manently remedied by reversal of

b. when the delay circuit
and/or when the
equal to the input period.

1-10-psec range to overcome the effects of stray

(V204A) to the grid (pin 2) of V205A, the delay ampli-

is

set at mimimum, the sweep must rise only about 10

if

nonlinear and closely matches the exponential, result-

V204B, the reset trigger amplifier, to conduct,

C234 to start the coincidence gate. The mono-

V204B, producing the negative pulse to restore

warmup, if V202 comes on first. (This can be per-

delay control

R232 provides an adjustable step of

1-sec range to compensate for the

R283 provides a step to speed up the be-

is

coupled by a cathode

is

a Schmitt

is

used to trans-

delay readings on the 10-psec-100-psec

the delay sweep were linear and if the vol-

R237, the change in voltage with

thelapse oftime

V202,

V202. This

S202, which momentarily removes

V201 and V202.)

is

used as a frequency divider

is

set to produce a delay nearly

is

done

4.4

COINCIDENCE CIRCUITS.

4.4.1 GENERAL. The 3-1000-psec monostable gate
by the negative delay reset trigger. In normal operation the posi­tive early transition of this gate turns on the coincidence ampli-

fier.

The pulse of plate current of the coincidence amplifier is
inverted by
conduction. The delay trigger generator develops the delayed

trigger in an inductor-diode pulse-forming network in its plate.

This circuit, the following pulse amplifier, and cathode follower
are identical in design to the equivalent circuits of the input
system explained in paragraph 4.2. The delayed trigger is fed to
one side of the SWEEP TRIGGER switch
trigger to the other. Operation of this switch causes the sweep
to be started by either the delayed or the direct trigger.

tion as described in paragraph 1.3.3, the sum of the
gate from V206 and an input pulse from J201 (POS) or J205
(NEG)

on. The coincidence amplifier bias is increased as the COIN-

CIDENCE SENSITIVITY control

wise. The

conduction when the sensitivity is reduced. The combination of

the gate and positive pulses at the junction of R289 and

will switch V207A on and produce the delayed synchronizing

signal.

4.4.2 COINCIDENCE GATE CIRCUIT. The right-hand side of
the 3-1000-psec monostable gate,
ing with its cathode near -80 volts and its grid slightly positive
with respect to cathode. The plate current of this tube, flowing
through
tage, which normally keeps the left-hand side of
With this tube off, its cathode is slightly negative with respect
to ground because of the forward drop of
lay reset trigger starts the regenerative action of the monostable
gate, during which the right-hand side of
ing the left-hand side on. After switching, the grid of the left­hand side
tive with respect to ground; thus
R251
of V206-left. The "offn time of V206-left depends on its plate
swing and the r-c time constant controlled primarily by C235,
R254, and R255. The "off" time of V206-right is controlled as
R253 varies the plate swing. C253 and R288 alter the initial
shape of the timing grid waveform for

timing down to 3 microseconds. When the timing r-c combination
has discharged enough for the right-hand tube again to go into

conduction, its plate voltage begins to fall, lowering the grid
voltage on the right-hand side, and the circuit regenerates and

returns to its original stable state, terminating the gate. The

gate
through

4.4.3 COINCIDENCE AMPLIFIER. When the 3-1000-psec gate

is

off, grid 2 of V207Ais about -10 volts; while it

is

near ground potential. R265 in the cathode of V207A

COINCIDENCE SENSITIVITY control, producing from

volts of additional bias for this stage. In the NORMAL position,

the

3 volts of bias alone will not hold the stage in cutoff when

T201 to drive the delay trigger generator stage into

(S203), and the direct

When the coincidence system is to

is

required to turn the coincidence amplifier stage

(R256) is turned counterclock-

3-1000-psec gate alone can not switch V207A into

R256, R257, and R249 to ground, produces a bias vol-

is

at ground potential and its cathode is slightly posi-

D205 is a high resistance, and

is

a feedback resistor, which stabilizes the plate durrent

is

directly coupled to the grid of the coincidence amplifier
R289. The resistive adder is compensated by C254.

beused for time selec-

V206B, is normally conduct-

D205. The negative de-

V206B goes off, turn-

V2OG-right to permit smooth

is

opened

3-1000-psec

V206A off.

is

on, the grid

is

3 to 33

R290

the

'

GENERAL RADIO COMPANY

its grid rises to ground. When the COINCIDENCE SENSITIVITY
control
tion, the circuit
coincidence operation, the same rapid rise of plate current in

V207A as that produced by the early transition of the 3-1000-psec

gate must be obtained; thus fast triggers are necessary to operate
the coincidence circuit. Their duration is relatively unimportant
but their rise time should exceed 0.2

4.4.4 DELAY TRIGGER AND SYNC GENERATORS. The net­work in the plate of
This pulse
sync applied to
presence of the delayed sync at the output terminal
by a stage comprising half of

chronizing pulse causes this stage to draw grid current, charging

C251. The discharge of C251 through R279 in the time between
pulses keeps
TOR lamp, to light.

4.5

4.5.1 GENERAL. The sweep circuits consist of a bistable con­trol multivibrator, sweep generator, amplitude comparator, and
reset trigger amplifier. This loop
that in the delay circuits. The only difference
is
a linearly rising sawtooth rather than the simple exponential
form produced in the delay circuits. The bootstrap-type sweep
generator produces a
which is fed through a cathode follower to the positive sweep
output terminals, and from this cathode follower through an am­plifier inverter to a negative-output cathode follower for
negative phase. Also, a single-tube amplifier-inverter stage
providedto produce negative and positive gates during the sweep
time.

4.5.2 SWEEP CONTROL GATE AND SWEEP GENERATOR. The

sweep gate multivibrator comprises

sociated components. The low plate voltage of
normally on, keeps V302 beyond cutoff. The plate voltage of
V302

(55 volts). Therefore, bothV303, the sweep generator, andV309,

the keyed clamp, are in conduction.

off and the resulting regenerative action causes

on rapidly. When

and the sweep

"networks in the plate circuit of

by

trolled by the SWEEP MULTIPLIER switch,

5.3, the SWEEP MULTIPLIER switch

SWEEP DURATION switch to

r-c network

zero-bias conduction, its plate voltage

goes off, the selected sweep-range capacitor begins to charge

through its associated resistance network towards

The grid voltage of the cathode follower rises and the cathode

follows. The cathode resistance of

high, so that the gain of this stage as a cathbde follower

is

moved counterclockwise away from the NORMAL posi-

is

prepared for coincidence operation. During

psec over a 5-volt interval.

V208A shapes the negative delayed trigger.

is

amplified and inverted inV208B to form a positive

V207B, the cathode-follower output stage. The

is

indicated

V104B. The positive delayed syn-

V104B off and causes V209, the DELAY MONI-

SWEEP

generated by a bootstrap-type sweep circuit, which produces

S301, the SWEEP DURATION switch. Capacitance

The voltage at grid 2 of

is

only slightly positive with respect to the grid. When V303

CIRCUITS.

is

identical in configuration to

is

that the sweep

positive-going, linearly rising sawtooth,

V301 and V302 and their as-

V301, which

is

very nearly equal to the positive power supply voltage

When a negative sweep trigger

V302 comes on, V303 and V309 are turned off,

is

started. Sweep timing

is

C321, R323, and R329. Initially, with V303 in

V304A

is

received, V301

is

controlled by the r-c

V303. Resistance

S302.

is

shown set to

3 psec. Thus the sweep-timing

is

very nearly at ground.

is

low and its cathode voltage

V304 with V309 off

is

V302 to switch

is

controlled

In Figure

+300 volts.

is

is

the

is

is

turned

con-

1,

the

very

ap-

proaches unity. The rising cathode voltage
C330 and drives the cathode of D303 positive. D303 opens, and
the plate-timing networks for
cathode of
of

1

cathode of
current through the timing resistor would be constant. If this
happened, the sweep would be ideally linear. The small depar­tures of the sweep with
from a cathode-follower gain of unity. A very large resistance is
thus needed in the cathode of
this cycle. The linearly rising sweep voltage always attains an
amplitude of about 140 volts at the grid of
plitude comparator. The d-c reference voltage for this stage
fixed to establish the correct sweep amplitude. When the sweep
has attained the 140-volt amplitude,
voltage rise at the plate. This causes
ducing the negative reset trigger that turns
on. The sweep gate is now reset to its normal condition. The
sweep generator
clamp
The conducting sweep generator can quickly reduce the voltage
across the sweep-timing capacitor to a small value, but the vol­tage at the cathode of the cathode follower,
duced by the discharge of strays and by the replacement of
charge on the bootstrap coupling capacitor
increase recovery time, this voltage must be brought back to its
quiescentvalue as quickly as possible; therefore, the plate cur­rent of
the reset cathode follower. The grid of V307A
by differentiation of the negative sweep voltage at
voltage spike causes

creases the screen voltage on

rent during the discharge interval.

to the pulse-timing amplitude comparators to provide timing trig-

gers to start and stop the main pulse.

ode follower for the positive sweep phase. Part of the positive

sweep voltage from the cathode of
verted by
SWEEP NEG output terminals through cathode follower

V310B through C331 to cause the spike of positive voltage at

the grid of

of

C331 through R369 cuts V310B off. The rise in plate voltage

of

V310B ionizes theSWEEP MONITOR lampV311 and indicates

the presence of the sweep at the output terminal.

V301 and

sweep gate

is

present at the plate. This push-pull gate waveform
nected through
GATE output terminals on the panel.

4.5.3 SWEEP RESET SYSTEM AND SWEEP PROTECTIVE
CIRCUIT. The sweep-generating loop has the same monostable
characteristic as the delay generating loop; that
gate
amplitude comparator triggers and feeds back a stop trigger to
close the gate. If, because of rapid

V304. If the gain of V304 were exactly unity, a rise

volt at the grid of V304 would cause the same rise at the

V304 and an equivalent increase in B-plus, and the

is

brought back into conduction, the keyed

is

turned on, and the sweep-timing capacitor

V309

is

increased during the discharge period by V307A,

The positive sweep at the cathode of

V307B, producing the negative sweep fed to the

The trailing edge of the negative sweep drives the grid of

V310. Grid current charges C331, and the discharge

The grid of

is

opened by the sweep trigger, the sweep rises until the

V305B

is

thus positive during sweep time. The positive

is

present at the cathode, and an equalnegative gate

1-pf coupling capacitors C339 and C338 to the

V303 are carried up along with the

linearity are due to small departures

V304 during the active portion of

V306 triggers, producing a

V307 to conduct, and momentarily in-

V309, increasing its plate cur-

V308

is

directly connected to the plate of

is

coupled through

V306, the sweep am-

is

V305A to conduct, pro-

V302 off and V301

is

discharged.

V304, must be re-

(C330) by V309. To

is

driven positive

V308B. This

V304

is

connected

V308A

is

the output cath-

is

amplified and in-

V308B.

is

con-

is,

when the

warmup of V302 or simul-

TYPE

1391-B

PULSE, SWEEP,

taneous triggering of both sides of the sweep gate, the sweep
fails to reset, this loop will come to an equilibrium condition,
where the sweep voltage
parator
artificial reset trigger must be given the sweep control gate
multivibrator. This is accomplished by the momentary grounding
of the cathodes of V301 and
S202, which causes the sweep gate to reverse its state.

the grid of

sistors of

ing, a high current could be drawn through

series, damaging these tubes. Because of these possibilities,

the cathodevoltage of V304 must be prevented from remaining in

a highly positive condition for a very long time. Protection
afforded by a system in which a network consisting of R319,
C337, and R320 establishes a grid voltage normally negative on

V310A. If the sweep circuit fails to reset, C337 charges to

voltage sufficiently positive to cause V310 to conduct. When
V310 conducts it decreases the grid voltage of V304 and lowers
the cathode voltage sufficiently to protect all tubes and com­ponent

4.6

start and stop triggers produced by amplitude comparators V401
and V402 (see Figure 5.4). These comparison circuits are pro­vided with d-c reference voltages derived from bleeders in the
30Q-volt regulated supply. A calibrated voltage along R409 sup­plies
from R410 supplies the stop comparator,
voltage from

the left-hand

in turn as the sweep voltage rises to become equal to the ref­erence voltages. Since the sweep
the amplitude comparators draw a constant current from the ref­erence voltage potentiometer. Hence, both the plate and cath­ode of the comparator circuit are connected to ganged potentiom­eters, maintaining the supply potential for the comparators con­stant regardless of the potentiometer setting. The amplitude com-

parison take-off voltages are calibrated at both the minimum and

maximum voltages for both the PULSE DELAY and DURATION
controls by

regulated power-supply voltage
parison voltage
connection causes a minute variation in the d-c amplitude com­parison potentials with line voltage, and
for small shifts of pulse position due to line-voltage (and there­fore heater-potential) changes. As an example of the operation

of two amplitude comparators (see Figure

put sweep voltage

duration is 3

put pulse with

and with a
PULSE DELAY

the PULSE DURATION control 40 volts above the PULSE DELAY

control, or at a potential of 80 volts. The start amplitude com-

parator would then trigger one-third of the way along the sweep

at
way along the sweep at 2

is

stable and "locked out". Under these conditions, an

In case of a "lock out" or a failure of V303, V304 will drive

V308A to a high positive value, and the cathode re-

V308 will be damaged. If V303 fails withV309 conduct-

s.

PULSE-TIMING CIRCUITS.

V401, the start comparator, while an equivalent voltage

V304

grids of V401 and V402, and these stages trigger

R407, R408, R411, and R412. A small amount of un-

pickoff network through R428 and R429. This

psec. Also, suppose

1

psec of delay from the leading edge of the sweep

1-psec duration. Under these circumstances, the

controlwill be set at a potential of 40 volts and

1-psec, and the stop amplitude comparator two-thirds of the

is

high and the sweep amplitude com-

V302 through the RESET switch

V304 and V309 in

The pulse

is

connected through precision attenuators to

is

is

fed across the amplitude com-

is

120 volts in amplitude and that the sweep

it

psec, resulting in a time between trig-

is

normally timed by

V402. The rising sweep

linear, it

is

is

necessary that

serJes to compensate

1.6b), suppose the in-

desired to start the out-

is

AND TIME-DELAY GENERATOR

1

gers produced by these two circuits of
duration.

V401 and V402 are Schmitt circuit amplitude comparators
similar in form to the equivalent comparators of the delay and
sweep circuits. The left-hand section of each tube is normally
off, the right-hand section on. When the rising sweep voltage

reaches the critical level at which the left-hand side will con-

duct, the circuit regenerates, turning the right-hand side off and
producing a fast-rising positive trigger. This positive trigger
coupledin the start channel via C403 and R421 to the start-chan­nelhalf of S401, and applied to the grid of buffer tube V403. The

resulting negative pulse at the plate of

and further amplified and shaped by
a fast negative pulse. This pulse flips
pulse. The function of S401 has been described in Section

Note that the positive trigger pulse marking the beginning of the
pulse is produced across R427 by the plate current of

a

connected via S401 to the START binding post. The circuit ac­tion and connections of V404 and
and amplifier, are identical with those of the start channel.

4.7

PULSE-GENERATING CIRCUITS.

4.7.1 GENERAL. The pulse-generating circuits consist of a
bistable multivibrator, identical to those in the sweep and delay
circuits. This multivibrator is started and stopped by the trig­gers derived from the pulse-timing circuits or by externally gen­erated triggers. The bistable multivibrator controls the state of
a bistable push-pull pulse amplifier consisting of two power am­plifier pentodes, which in turn are directly coupled to a pair of
driver amplifiers. These amplifiers drive the output-pulse power
output stage. Since the system
coupled throughout, the entire circuit
drawn from all power supplies
put-power amplifier
nals necessitates the use of a number of different power-supply
voltages. These voltages are all unregulated, so there would
normally be a variation in pulse amplitude with line voltage;
however,
output tubes to decrease the effects of line-voltage variation.

4.7.2 The right-hand side of V501
that
This voltage
ing in
V501-left
on.

volts across
lated negative by the current flowing in
V505
plate voltage of this stage due to plate current in
causes V506 to conduct. The plate current of V506 throughR528
and R530 holds the gridof output tubeV508 about 25 volts nega-

tive with respect to its cathode, and this tube

off, V507 will be at zero bias and conducting. These are the qui­escent conditions before a start pulse
V501-left on. When this happens, all tubes on both sides reverse
their conduction states. Thus

V511 regulates the screen-to-cathode potential of the

its

plate voltage

is

V502, so V501-left

is

off, the grid of driver V503

When on,

R507 and R545. The platevoltage of V503

is

heldin cutoff. Since amplifierV504

is

is

translated negative 100 volts by the current flow-

V503 draws about 60 ma, producing a drop of 36

is

itself direct coupled to the panel termi-

about f 140 volts with respect to ground.

is

in plate-current cutoff. Since

V507 will be turned off and V508

psec, the desired pulse

V403 Is inverted by T401

V405, the start amplifier, to

V501 over to initiate the

V406, the stop-channel buffer

is

both push-pull and direct

is

bistable, and the current

constant. The fact that the out-

is

normally in conduction so

is

positive and V503

V509-left, and driver

is

off, the translated

is

off. Since V505

is

fed via D501 to turn

is

1.

V405, and

is

is

trans-

V509-right

is

GENERAL RADIO COMPANY

will go on to produce a negative pulse. DC connections through­out cause the entire system to be bistable

With the pulse amplitude switch set for a maximum, output
tubes V507 and V508 conduct about 160 ma of plate current.
Voltage produced by this current in
tutes the output pulse. Negative pulses are, for example, pro­duced when the plate current of
ohms) to produce -7.5 volts with respect to ground
50 ohms.
output voltage. Note that the link between
opened to insert a battery or dc power supply to translate the dc
component of the pulse away from ground.

age (maximum pulse amplitude), about 100 ma of the current in
the "onn output tube flows through the
"normaln conditions there will be 160 ma in

V506. The additional 60 ma flows in R537.

for maintaining plate voltage on the driver tubes (normally main-

tained by conduction of the output tubes). Therefore, as the
PULSE AMPLITUDE switch setting

through R575 are switched in from ground to cathodes of V507
and V508, reducing screen voltages and thereby maintaining
plate voltages.

voltage of the output stage. The screenresistance
R566) for V507 and V508

age. The pulse current

transients by
to the amplitude control network.
follower, whose grid voltage
ing of
tween
that the line voltage decreases. The -200 volt supply feeding
the cathodes of V507 and V508 becomes less negative and the
screen voltage on these stages tends to decrease, decreasing
plate current. Actually the -550-volt supply becomes less nega­tive by an amount which, when referred to the cathode of
exactly equals the change in cathode voltage on V507 and V508.
Thus the plate current at these stages tends to remain constant,
and is, in fact, affected only by changes in heater voltage.

4.8

4.8.1 GENERAL. All necessary power supplies are in the Type
1391-P2 Power Supply Unit. This supply provides the four

S501 controls output impedance, and consequently

When V507 and V508 are conducting with full screen volt-

If pulse amplitude is decreased, means must be provided

Pulse amplitude is reduced by reduction of the screen

is

increased to decrease screen volt-

is

stabilized against line variations and

V511, which controls the screen voltage supplied

is

R578, R579, V512, V513, and V514 with this network be­+300volts regulatedand -550 volts. Suppose, for example,

POWER

SUPPLIES.

R548 through R557 consti-

V508

is

turned on in R548 (50

(J507) behind

3507 and J508 can be

*on" driver tube. Under

V507 and 100 ma in

is

decreased, resistors R567

(R558 through

V511

is

essentially a cathode

supplied by the network consist-

V511,

6.3-volt heater supplies and the nine d-c power supplies required.
10-conductor cable carries the four heater

One

115-volt conductors required to operate the blower. The four
heaters are identified by the letters
plitude comparator,

is

a shielded, low-noise winding that provides heater voltage for
the various amplitude comparators of the input, delay, sweep,
and pulse-timing circuits. The ground bus
ground potential for tubes whose cathodes are close to ground,
and the N bus supplies those tubes whose heaters normally run
at 150 to 200 volts negative. The heater connection of each
tube is identified by the key letter printed on the heater termi­nals of that tube in the circuit diagrams, Figures 5.1 through 5.6.

4.8.2 PLATE SUPPLIES.

4.8.2.1 General. All supplies use silicon rectifier circuits.
Those providing appreciable power are full-wave doublers, while
the low-drain bias supplies are half-wave rectifiers. The plate

supplies, in the order shown from top to bottom of the elemen-

tary diagram on the back of Figure 5.6, are:

a. a 110-volt 200-ma doubler supply added to a 300-volt

doubler

provides plate voltage for the

andV504 in the pulse-generating section and +55 and -150volts
for the bistable gate circuits.

V509 for the pulse output stage and pulse amplitude regulator.

4.8.2.2 Regulator. A Type
to the proper operating point to produce a 300-volt output by

means of the plate current of V602 flowing through
level of this plate current is controlled by the grid voltage on
V602, controlled by R612. R612 therefore determines the regu­lated output voltage. The 150-volt reference voltage for the cath­ode of
the 410-volt supply
grid network of
input voltage. When the output voltage tends to rise due to an
increase in line voltage, rhe grid voltage on
creasing the bias

compensation produces a negative slope of output voltage with
increasing line voltage over the range from 100 to 130 volts.

From 105 to 125 volts, the output voltage from the supply changes
by less than one-half volt.

supply to produce f410 volts unregulated. This supply

a second 300-volt doubler providing

b.

c. a -200-volt doubler for the pulse output stage.

d. a half-wave rectifier supplying additional 340-v bias to

V602

is

G

for ground, and N for negative. The A bus

+300-volt regulator.

6AS6 series tube (V6Ol)

produced by V603. Some unregulated voltage from

is

developed across R607 and

V602. This provides compensation for changing

0nV6Ol and lowering the output voltage. This

P

for positive, A for am-

is

palrs and the

a heater winding at

+I40 volts for V503

is

biased

R605. The

is

added

to

the

VG02 increases, in-

TYPE

1391-6

PULSE, SWEEP, AND TIME-DELAY GENERATOR

Section

SERVICE AND MAINTENANCE

5.1

GENERAL.

Radio instrument attests the quality of materials and

ship in our products. When difficulties do occur, our service

engineers will assist in any way possible.

In case of difficulties that cannot be eliminated by the use
of these service instructions, please write or phone our Service
Department, giving full information of the trouble and of steps
taken to remedy it. Be sure to mention the serial and type num­bers of the instrument.

Before returning an instrument to General Radio for serv­ice, please write to our Service Department or nearest district
office (see back cover), requesting a Returned, Material Tag.
Use of this tag will insure proper handling and identification.
For instruments not covered by the warranty, a purchase order

should be forwarded to avoid unnecessary delay.

5.2

SERVICE.

5.2.1 GENERAL. The Type 1391-B Pulse, Source, and Time­Delay Generator is designed for easy servicing. There are many
front-panel connections to the circuits, and test points are pro-

vided for oscillographic presentation of stage performance wher-

ever there is no panel connection for the stage. The following

notes are based on signal-tracing methods in order of increasing

difficulty in required measurements. First isolate the trouble by
front-panel observation, using an oscilloscope. Then use Table

5.2 and paragraph 5.2.2 to isolate the defective stage or stages.
Troubles in operation can be divided into two classes:

faulty or erroneous operation of a circuit (or perhaps of one range
of one circuit), and complete failure of a group of circuits or of

the whole system. Troubles in the first category are obviously
easy to remedy. Faulty or erroneous operation of one range alone
points to the components actually switched on in that range.
Faulty operation on all ranges of a multirange circuit usually
points to fixed

circuit, etc. Such trouble can usually be remedied by direct in­vestigation of the tubes or components involved and reference to
the service data on waveforms and voltages.

When replacing a component on an etched board, be careful
not to destroy the bond between board and etched wiring by
heat or by force. When removing the defective component,
firmly grab the wire at the component side (the component
may be clipped off first), and
ply just enough heat to the solder to free it. Before insert­ing the new component, make certain that an unobstructed
passage exists, either by carefully drilling through the com­ponent side or by removing the solder from the hole. When
using the soldering iron to remove solder, draw the solder
back along the conductor from the tab with quick strokes.

Never apply the soldering iron to the etched board for more
than five seconds at a time.

The two-year warranty given with every General

workman-

components,tubes, a power supply common to that

CAUTION

then, pulling on the wire, ap-

5

If the position of the board prohibits the above pro­cedure, many components can be replaced as follows: des­troy the old component, preserving enough wire to attach the

replacement, then solder the new component in place.

5.2.2 ISOLATION OF TROUBLES.

5.*2.2.1 General. Set allcontrols to the standard positions listed
in paragraph
are plugged in on the rear panels of power supply and main unit.

Also be certain, by measurement at the PRF DRIVE terminals,
that an adequate signal

to determine which signals are missing or not functioning pro­perly. The 13 columns of signals and indications of signals pre­sent (P) or absent (A) will isolate the circuit action at fault.
After finding the defective section, use an oscilloscope to ob­serve the waveforms at the test points of the defective section.
Proceed in order of increasing numerical value through the cir-

cuit to isolate the defective stage. Then measure voltages and

check them against Table 5.3.

5.2.2.2 All Signals Absent and Indicators Do Not Light. This

is

an indication that the defect
generating the direct trigger
is a failure of the power supply feeding these stages. Either pos­sibility can be checked first. Remove the cover and left side pan

of the instrument. Voltages can be checked at input power plugs

or at the rear skirt of the instrument. (See Figure

5.2.2.3 Direct Sync Present, DELAY MONITOR Lamp Lights
Onlv When Direct Svnc Pulse
Terminals. This indicates that neither sweep control multivibra­tor will operate. The only common connections between the cir­cuits are the +55 -150, and -200-volt power supplies. Check
the

+55 and -150-volt supplies first. The -200-volt supply pro-

vides the bias for the direct trigger pulse amplifier. Failure of

this supply could cause the trigger amplitude to decrease enough
to cause failure of the control multivibrator. Check the direct
trigger amplitude (at
are

satisfactory.

5.2.2.4 Direct Svnc Pulse Absent or Low. Balance of Instrument
Functions Properly. This symptom points to a weak tube or de­fective component in the direct sync output circuit. Check the
direct sync amplifier tubes

5.2.2.5 Delay Circuit Does Not
Flipped. Determine whether it
the main delay group, or the output circuit that has failed. Re­move the cover of the instrument and check for the presence of
a positive delay gate at

necting oscilloscope). If the gate exists there, the difficulty

2.3. Be sure that the power is on and that all cables

(1 to 10 volts)

Using Table 5.2, observe output signals and monitor lamps

(VlOlA, V102, or V103A), or else

is

AT205) if the -150- andt55-volt supplies

V103B and V104A and components.

TP201 (flip RESET switch after con-

is

present.

is

either in the input circuit

5.5.)

Connected to

Functionwhen RESET Switch

is

the coincidence-gate circuit,

POS

-

- -

COTNC

- - --

DRIVE

-

is

is

GENERAL RADIO COMPANY

in V206 (coincidence gate monostable) or
nents. As a first check, make sure that the delay reset pulse
has the correct amplitude by checking the pulse from
against Figure 5.7.

Since the main delay circuit

all circuits (V201 through V205) must be functioning, a special

procedure can be used to isolate the defective component. (Re-

fer to paragraph 5.3.1.)

5.2.2.6 No Delay Sync Pulse Present When Direct Sync Pulse
Is Connected to POS COINC DRIVE Terminals. 'Throw the
SWEEP TRIGGER switch to DELAYED. If the sweep circuit
does not start, the difficulty is in the delay sync amplifier
(V208B) or cathode follower (V207B) or their components.

5.2.2.7 Delay and Direct Triggers Normal; Sweeps,
Pulses Missing. This indicates that the sweep

V303, V304, V309, V305A, and V306)

set pulse must be present to reset the bistable gate, the loop can
"lock out': as can the delay circuit. Troubles are most easily
isolated by means of the special procedure outlined

5.3.

5.2.2.8 Defective or Missing Negative
V307B, V308B, and their components. If only the SWEEP MONI- 5.3, after making sure of the state of the delay gate (V201 on,

TOR lamp functions, check

5.2.2.9 No Main Pulse, No Output Pulse From START Trigger
Terminal When PULSE START STOP TRIGGER Switch
INTERNAL (NORMAL) Position. This indicates a failure in the
start channel
start trigger -at
the trouble must be in

5.2.2.10 No Main Pulse, No Output Pulse From STOP Trigger
Terminal When PULSE START STOP TRIGGER Switch
INTERNAL (NORMAL) Position. This indicates failure
V404, or V406. First check TP402 for the positive stop trigger
as shown in Figure
with V404 or V406.

5.2.2.11 No Main Pulse, Both Start and Stop Triggers Present
When PULSE START STOP TRIGGER Switch
(NORMAL) Position. This usually indicates a failure in the
pulse source itself. First check the operation of V404 and V405
by checking their waveforms at
pulses are as shown in Figure 5.7, proceed to a detailed check
of the pulse source (paragraph 5.3.2).

5.2.2.12 All Signals Present Except Sweep Gate. Since the
sweep gate output system consists only of a simple pulse-split­ter from the sweep-gate bistable multivibrator, which must be
operated to produce the sweep, the trouble can only be
or associated components.

5.2.2.13 Negative Sweep and Positive Sweep Both Missing,
Pulse-Timing Circuit Normal. The only circuit common to both

negative and positive sweep phases after the pulse-timing sweep

is

taken out

Check this circuit.

5.3

SPECIAL TECHNIQUES FOR TROUBLE-SHOOTING DE-

(V401, V403, or V405). First look for the positive

TP401 shown in Figure 5.7. If the trigger exists,

is

that of V308A and

V310B and associated components.

V403, V405, or associated components.

5.7. If the trigger exists, the difficulty

LAY, SWEEP, AND PULSE-TIMING CIRCUITS.

bistable characteristic of the delay and sweep loops when a

its

associated compo-

TP203

is

a feedback loop in which

Gates and

loop (V301, V302,

is

defective. Since the re-

in

paragraph

Sweep Only. Check of course, be measured and checkedagainst those given inTable

is

in

is

in

inV402,

is

is

in INTERNAL

TP403 and TP404. If these

inV305B

its

associated components.

The possible

failure occurs, and the definite bistable characteristic of the

pulse generator make trouble-shooting these circuits somewhat

more complex than the straightforward signal-tracing techniques

that suffice for the other circuits. Paragraph 5.3.1 below

lines the techniques for the sweep and delay circuits, and
graph 5.3.2 that for the pulse generator.

5.3.1 DELAY AND SWEEP LOOP TROUBLE-SHOOTING. AS­sume that the delay reset pulse amplifier
burnout. The first direct trigger received by
control circuit upon
The delay sweep will rise and cause V205 to switch to generate
the driving pulse for

pulse. The loop

off, V204A in grid current, V205A on, and V205B off. The same
condition could obviously be caused by a defective V204, V205,
etc.

Several procedures can be used to isolate the defective

components.

weak or failed vacuum tube,

tubes, one by one, with tubes known to be good. Voltages can,

V202 off).

difficulties in each loop:

a. Connect an oscilloscope set for d-c operation to

(or POS GATE).

b. Set DELAY (or SWEEP) RANGE switch to the longest

range,

c. Connect a low-frequency (10-20 cps) source to the PRF

DRIVE terminals.

d. Now flip the RESET switch. V201 (301) should go on and
be turned back off by the next low-frequency direct trigger. If
V201 or V301 does not switch on, the control bistable gate
defective. The defect can be remedied either by tube replacement
or voltage measurement.
pulse is actually produced by the momentary grounding of the
cathode of
the delay circuit
must also be suspect. If the delay circuit fails to change state,
produce a reset pulse by touching a grounded, discharged
100-ppf capacitor on TP203. This will produce a negative pulse
to turn V202 off. If the bistable switches when this
V204B or one of its components

ing, the trouble can easily be located by the substitution of a
reset pulse for that of the defective loop. The procedure is as
follows:

(I) Delay Circuit: The falling edge of the positive output

is

substituted for the missing reset pulse.

the sweep and delay circuits are started simultaneously.

control to 10-100
produce a

(DELAY RESET PULSE) through a jumper and 100-ppf capaci­tor.

since

The following

1

second (120,000 psec sweep range).

V204B by a discharged capacitor (C221); so that if

If the bistable gate of the defective circuit

(a) Set the SWEEP TRIGGER switch to DIRECT so that

(b) Set up a 10-kc repetition rate,

50-psec pulse on the 60-psec sweep range.

(c) Connect the PULSE POS output terminal to

warmup will flip V202 on and cut off V203.

V204B, which cannot produce the reset

is

now stable, with V201 off, V202 on, V203

it

is

probable that ,.he failure

it

would be advisable to replace

is

a rapid and effective means of locating

In the delay circuit, the manual reset

is

involved, V204 and its associated components

is

psec, and set the sweep and pulse controls to

V204B should fail by

V201 of the bistable

is

caused

faulty.

set the DELAY RANGE

is

out-

para-

by

TP201

is

done,

function-

TP203

a

is

TYPE

1391-8

PULSE, SWEEP, AND TIME-DELAY GENERATOR

(d) Flip the RESET switch and check for gate waveform

at

TP202. The delay sweep will reset simultaneously with the
trailing edge of the positive pulse, and the delay sweep can now
be checked at
the bistable gate as directed in the beginning of this section.

(2) Sweep Loop: The delay reset pulse can be substituted

for the sweep reset pulse by means of a jumper containing a

100-ppf capacitor connected between TP203 and TP305.

(a) Set the SWEEP TRIGGER switch to DIRECT.
(b) Setup a 1.0-kc repetition rate, set the DELAY controls

psec. The sweep will be started by the direct trigger and

for 60
will stop at the setting of the delay control. Check for the sweep

gate at its output terminals.

(c) The sweep can now be traced through

and the defective stage isolated by signal-tracing methods. In

order to check the sweep amplitude selector,
control must be advanced beyond 60
sweep amplitude selector should trigger.

e. The following symptoms are possible:

(1) Delay Circuit: The normal condition with the DELAY
controls set for maximum is
volts, where
TP202 indicates a defective V203 (grid, cathode, or screen short)
on a nonconducting V204.A steady high voltage could be caused
either by a defective

grid-cathode short in V205A will produce a voltage at TP202
that varies as the DELAY control setting

(2) Sweep Circuit:

V303 and V309, that must be turned off by the gate. If V303 fails
to go off, the sweep voltage will not rise. If

off, there will be a small step until
current.

5.3.2 TROUBLE-SHOOTING THE PULSE SOURCE.
can be absent for either of two reasons:
vibrator

missing. Proceed as follows to isolate the difficulty:

a. Having determined that both start and stop pulses are pre­sent (paragraph
waveforms at

b. If the multivibrator
PULSE START STOP TRIGGER switch in the EXTERNAL OUT

position, and, using a 20,000-ohm-per-volt voltmeter (or VTVM),

measure the quiescent d-c voltages at the points in Table
This

is

ance. (Voltages given in the table are typical for 115-volt line
and should not vary by more than 10 percent.) Note that at
and TP506 the first voltage given
position, and the second
is in the pulse-on state
listed applies and the voltage states at all succeeding test
points and at pulse output terminals will reverse. Any abnormal
voltages indicate difficulties that can be remedied by replace­ment of tubes or components.

TP202. If the gate still does not function, test

TP302-TP305,

V306, the delay

psec, the point where the

a

sawtooth waveform rising to 150

V204A draws grid current. A steady low voltage at

V203 or an open R234. An open R234 or a

is

varied.

Inthe sweep circuit, there are two tubes,

V309 does not shut

V304 begins to draw grid

A

pulse

(1) the control multi-

is

defective, or (2) power-supply voltage

5.2.2.11), using an oscilloscope, compare the

TP501 and TP502 with those shown in Figure 5.7.

is

operating correctly, place the

is

incorrect or

5.4.

a quick check on both tube and power-supply perform-

TP501

is

for the normal quiescent

is

the active pulse interval. If the gate

(V502 on), then the second voltage

5.5

TROUBLE-SHOOTING CHART.

tion of some of the more likely causes of malfunction, together
with suggested adjustments and replacements.

5.4

SETUP PROCEDURE FOR THE PULSE DURATION AND

POSITION

necessary only when a potentiometer
the mechanical assembly
object
cal stopping action

the potentiometers, and so that the DURATION dial can never be

set to produce a "negative" pulse duration.

in order from the front panel toward the rear of the instrument
(see Figure 5.9).

and R410 and

a. Loosen the interlocking collars (A, B, C) between R403

and

b. Connect an ohmmeter between the center and counterclock­wise (facing from the panel) terminals of
the DELAY dial, set the potentiometer to give a reading of be-

tween 20 and 100 ohms.

c. Check the synchronization of R403 by connecting the ohm­meter between the center and counterclockwise terminals of
The reading should be between 20 and 100 ohms. Adjust,

necessary, by loosening and rotating collar A (Figure 5.9). Re-

tighten collar A.

d.

hold the DELAY dial to the shaft, and set the DELAY dial to the

etched 2.75-5.50-11.00 point. Tighten the set screws to secure
the

0.25-0.5-1.0.
e. By means of the DURATION dial, set R410 to read be-

tween 20 and 100 ohms on an ohmmeter connected between its
center and counterclockwise terminals. Check
chronization with R410 by reading the resistance between its
center and counterclockwise terminals. Adjust, if necessary,
by loosening and rotating the rear collar (D, Figure 5.9) for
reading of between 20 and 100 ohms. Retighten D.

f.

the fixed stop

g.

the set screws on the knob. Then, without disturbing the posi­tion of the shaft, set this dial exactly to the 2.5-5.0-10.0 point
and tighten the set screws. (Do not disturb the DELAY dial set-

ting; it must be set to the 0.25-0.5-1.0 point.)

h. Without disturbing the DELAY dial setting, move the

DURATION dial to its exact zero point. Rotate the front inter­locking collar (B, Figure 5.9) counterclockwise until it engages
the pin on the rear interlocking collar C. Then tighten collar
to the outer shaft.

i. Check results as follows:

RATION dial can be set to any calibrated point within its range,
but cannot be set outside its range in either direction.

RATION delay will indicate exactly zero and will be immovable.

DIAL ASSEMBLY.

is

to adjust the potentiometer blades so that all mechani-

is

accomplished by panel stops external to

The four potentiometers are

R409 and R403 are the two pulse delay controls,

R404 are the pulse duration adjustments.

R410.

Loosen the set screws (just behind the front panel) that

dial to the shaft, and move the DELAY dial to exactly

Rotate the rear interlocking collar (C, Figure 5.9) against

(S) and tighten it to the shaft.

Loosen the DURATION dial from the shaft by loosening

(1) With the DELAY dial exactly at 0.25-0.5-1.00, the DU-

(2) With the DELAY dial exactly at 2.75-5.50-11.00, the DU-

The following is a tabula-

The following procedure will be

is

replaced or a part of

is

damaged and must be replaced. The

R409, R403, R410, and R404,

R409 and, by means of

R404 for syn-

R403.

if

a

B

a. Ringing

GENERAL RADIO COMPANY

TABLE 5.1 TROUBLE -SHOOTING CHART

PULSE

Incorrectly terminated transmission lines, causing stray

ductance. 300-ohm twin lead properly terminated produces a
clean pulse.

in-

b. Overshoot

c. Pulse with two

distinct levels.

d. Hum on pulse

e.

Ramp-off

f. Inadequate

rise time

g. Positive sweep

and pulse timing

nonlinear (sweep

slope decreases).

Improperly adjusted oscilloscope and/or poor termination (see
a., above).

Incorrect bias supply adjustment (400-v supply) or abnormally

low line voltage. Readjust bias voltage by R616 on rear skirt

Or

of power supply. Adjust for pulse flatness.
ap.d/or V504.

V505 or V506 weak, or incorrect adjustment of -15C, +55-v

supply. Adjust R618.

Check that oscilloscope has adequate low-frequency response.

Check compensation of oscilloscope probe, if one
Calculate coupling time constant; it must be at least 10 times
as large as pulse transmitted to produce less than

Check typical rise times in Specifications. Remember that
system tolerance to stray capacitance decreases as output
pedance increases.
Check oscilloscope bandwidth, remembering that observed rise

is

time

Incorrect adjustment of
completely off. Make -150-v supply more negative or replace
V503,

that given by over-all system response.

Tobs

=px

SWEEP CIRCUIT

+55-, - 150-v supply so that V503

replace V503

is

used.

10%

rampoff.

im-

is

not

h. Negative sweep

nonlinear.

i.

Poor recovery
time (over 2 ysec
for 3-ysec sweep).

j.

V304 weak or
defective and
R335 and R336

excessively

k. Delay nonlinear

at top of scale,
period longer
dial reading.

hot.

than

Readjust R340 (this might benecessary when V307 is replaced).

Replace defective V309 or

Check V310, sweep protective tube and circuit, and repair if
necessary. To test circuit, pull V303 out of its socket and:

(I)

Check that plate voltage of V302 is positive with respect to

If

ground.
(2)

WithV302 off, measure voltage at TP303. It should be about

125 volts.

Nonlinearity of delay sweep due to:

(1) V203 not shutting completely off. Check
supply and
or

(2)

this voltage

If

it

is

higher, check V310 and associated circuits.

DELAY

V204 drawing excessive grid current. Replace tube.

CIRCUIT

V203.

V307.

is

negafive, flip the RESET button.

+55-, -150-v

I

TYPE

1391-6

PULSE, SWEEP, AND TIME-DELAY GENERATOR

DELAY CIRCUIT (Cont.)

1. Excessive jitter
on delay

syn-

Check line and noise on

+300-v regulated supply. Check V204

and V205 for heater cathode leakage.

chronizing pulse.

is

m. Large drift in

delay sync. pulse
(over 1: 1000) for

10% line change.

Occurs only when V205
necessary to compensate completely for a line change with
DELAY MICROSECONDS dial at a minimum. To establish value,
replace R219 with a 200-k resistor in series with a

replaced. Replace R219 with value

potentiometer and establish correct compensation by inserting
resistance for minimum drift as line voltage is varied
normal.

INPUT CIRCUIT

n. Loss of input

sensitivity.

o. Direct trigger

amplitude low

VlOl weak or R104 incorrectly adjusted. In either case, adjust
R104 to restore normal operation.

CheckV 103 for grid current by replacing it with a tube known to

(V

be good.

103 can be interchanged with V207.)

(less than 5 volts).

POWER SUPPLY

CAUTION: Be careful when servicing power supplies. The high-voltage supplies

are dangerous.

1-megohm

f

10% from

p. Short circuit in

a power-supply
component or a
burned- out

rectifier.

q.

Power - supply

about half its

normal value.

r.

Low output

voltage.

s.

Burned-out
or overheated
resistors in
filter networks.

Try to find source of overload with ohmmeter check. The

(1)

damagedrectifier

is

easy to find by visual inspection. Refer to

rectifier layout in Figure 5.13.

(2) Replace the defective components (or component).
(3) Then replace the defective rectifier.
(4) Carefully testrepaired

age at very low input voltages.

supplyby measuring the output volt-

(If possible, use a ~ariac@ to

increase inputvoltage slowly.) The power supply output should
be slightly higher at very low input voltages than the proportional
normal voltage.

Defective rectifier or half-wave rectifier operation. Replace de-

fective rectifier and then check associated filter capacitor.

Measure voltage across entire input capacitor in doubler

supplies, then across each half of doubler. Check (1)

elect-

rolytic capacitors and (2) rectifiers associated with low side.
Trouble must be isolated to either power -supply filter or main

unit. Hence:

(1) Break connection at either

SO602 or PL401 and insert

milliammeter between open connections.

(2)

serving current.

Turn on power and gradually increase line voltage, ob-

If

current value

is

too high, repair defective

circuit in the main unit. See Table 5.6.

(3) If current

is

still low, check electrolytic capacitors of
associated filter. If too high, check associated circuit in main
unit.

-

GENERAL RADIO COMPANY

t.

300-v output

not regulated,

POWER

Check V602 and V603. Component may be causing V602 to be
nonconducting. Check V601 for a grid cathode short.

SUPPLY

too high.

u. 300-v output

not regulated,
too low.

5.6

TROUBLE-SHOOTING PROCEDURE.

enable the user to pinpoint the circuit in which the trouble exists.

1

Columns
which indications

through

13

contain various sets of conditions, in the information in the lower part of that column.

as

listed in the left-hand column are either

Check V601 and the
in regulator, check output voltage and compensation in accord­ance with paragraph

Table

5.2

should present or absent. Simply determine the vertical column corres-

(Cont.

)

+450-v supply. After replacing any tubes

3.7.3.

ponding to the conditions present on the instrument, and refer to

TYPE

1391-B

PULSE, SWEEP, AND TIME-DELAY GENERATOR

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GENERAL RADIO COMPANY

TUBE

(TYPE)

VlOl

(5965)

V102

(6BQ7)

V103
(bug)

V104

(5963)

V201

(6485)

V202

(6485)

V203

(6AN5)

V204

(6AW8)

V205

(12AX7)

V206

(5965)

r

PIN

1

2
3
6

7

8

1

2
3

6
7
8

1

2

3

6
7

8
9

1

2

3

6

7

8

1

2

3

6
7

1

2

3

6

7

1

2

6

7

1

2

3

6

7

8

9

1

2

3

6
7
8

1

2

3

D-C

VOLTS

+

88

0

+

3.2

+244

0

+

3.2

+300

+

78

+

90

+245

+

90

+

90

+I20

-

12-8
+I90
+300

0
0
0

+300

0

+

17

+

48

0
0

-120

-110

+

40

-

55

-110

-120

-110

+

40

-

55

-110

+15

+

17

+

25

+

15

+

20

+

17
+300
+5

0
+I90
+275
+270

+

20

+

35

t280

+

34

+

35

+300

-

25

-

0.5

RES

TO

GND

120k

1

Ok

8.5k

6.6k
LOOk
320

5k

37k

6.8k

3.7k
120k

6.8k

1

Ok
Ilk
17k

l.lk

0

0

lk

0

230k

10k

9

5k
18M

0

6.8k

3.3k

6.8k

47k

3.3k

6.8k

3.3k

6.8k

47k

3.3k
107k
500k

16k

1.8k

22k

500k

0
lk

33k

lOOk

4.7k
42k
22k

7.8k

5.6k
27k

7.8k

0.7k

>3k

>0.2k

TUBE

(TYPE)

-

V207

(6U8)

V208

(6U8)

V301

(6485)

V302

(6485)

V303

(6AN5)

'

V304

(12BH7)

-

V305

(5965)

V306

(12AX7)

V307

(5965)

PIN

D-C

VOLTS

RES

TO

TUBE

(TYPE)

PIN

D-C

VOLTS

GND

6

-

7
1

2

7

2 -5

1

2

5
6
7

1

2
5
6

7,
1

2
5
6
7

1

2
3
6
7
8

1

2
3
6

7
8

1

2

3

6
7
8

1

2
3
6
7

33

-100

+300 3 +I80 10.7k

-

20 6

+

2.5 lk

-108

-110

-

23

-

55

-110

-115

-110

+

40

-

55

-110

+

6.3
0

+

2.5

+

14

0

+298

+

2.5

+

15

+300

+

2.5

+

15

+250

0

+5

+300

-

22

0

+295

+I50
+I50
+290

+

14
+I50
+300

+

21

+

38

+250

+1

5k

>2M

3.3k

6.8k

47k

3.3k

>5k

3.3k

6.8k

47k

3.3k

107k

0

>300k

1

6k
0

100

>300k

20k

0

>300k

20k
10k
33k

lk

5.6k

6.8k

5.6k

5.6k
40k
22k

47k

20k

22k

0
3 5k
12k
12k

12.4k

V308

V401

(12AX7)

V402

(12AX7)

V403

(6485)

V404

(6485)

V405

(6485)

V406

(6485)

V501
(5687)

8

+

1

+410

+

7

+

9

+300 0

1

+

5

+

6

+

1

+

6

+

7

-

1

+I91

2

+

+

3

6

t215

7

+

8

+23.3

1

+I88

2

+

3

+

6

+218

7

+

8

+

1

-

2

+

5

+265

6

+210

7

+

1

-

2

+233

5
6

+210

7

1

-

2
5

+I42

6

+305

7

1

-

2

+

5

t144

6

+305

7

+

1

+I31

2

+52

3

+

6

+

7

+

RES

TO

GND

10

31 19k

15 20k

0.6 107k

14 20k

38 12k

2 280k

33 470k

0.6 3M

9.3

23.3
24

9.5

23.5

22.2

23.5

3.4

0.3

0.3

3.5

0

0

31

0

0

42.5

0.3

0.3

52
52

41

3.5k
0

48k

46.5k
8k
8k

26k

8k

48k
46k

8k
8k

26k

8k

18k
32

1

Ok

34k
32

18k

0

1

Ok

34k

0
23k
32

1

33k
32
33k
32

9.5k
33k
32

500
180k

2.35k

2.3%

180k

TYPE

1391-B

PULSE, SWEEP AND TIME-DELAY GENERATOR

NOTES:

(1) Input resistance of d-c voltmeter must be several times
value listed in RES column.

(2) Panel controls should be set as follows:

TIME DELAY RANGE: 10-100 ms
COINCIDENCE GATE DURATION: CCW

COINCIDENCE SENSITIVITY: CW
MICROSECONDS: 1.00
PULSE AMPLITUDE: CW
OUTPUT IMPEDANCE: 150
PULSE DELAY: CW
PULSE DURATION: CW
SWEEP MULTIPLIER:
SWEEP SCALE: 6

10'

(3) Measure voltages with no input signal.
(4) Voltage conditions in push-pull stages of pulse-forming

circuits
(i. e., V501 voltages may apply to

(5) Operate RESET switch before making voltage measure­ments.

(6) All resistances are in ohms unless otherwise indicated
by k (kilohms) or M megohms).

(7) Resistance measurements were made with all terminals
of
SO401 grounded in the Type 1391

terminals were measured with Type 1391-P2 disconnected.

(V501 to V507) may be the reverse of those listed.

PL401 grounded in the Type 1391

V502, and vice versa.)

-B,

and all terminals of

-P2.

Resistances at PL401

GENERAL RADIO COMPANY

TABLE 5.4

VOLTAGES IN

THE

1.

Voltages in column labeled "Quiescent" are for the nor

ma1 position, those in the "Active" column for the active pulse

interval. If the gate
the "Active" voltage applies and the voltage stated of all suc­ceeding test points and at pulse output terminals reverse

roles.

2. Voltages should be measured with no input signal.

3. Switch settings:
OUTPUT IMPEDANCE: 150
PULSE AMPLITUDE: CW

4. Any abnormal voltages indicate troubles that

edied by replacement of tubes or components.

]PULSE SOURCE

is

NOTES

in

the pulse-on state (V502 on), then

canbe rem-

-

SUPPLY

+410

+300

+300

(f

+

55

-150

-

190

-290

+I40

-

425

POWER

1

0%)

TABLE 5.5

-

SUPPLY -CIRCUIT CONNECTIONS

PL401
PIN NO.

1

2

4

5
6

7

9

10
12

TUBES

V308B

VlOlA, V102, V104B, V203, V204A,

V205, V207A, V208, V303, V304,
V309, V306, V307B
VlOlB, V103, V104A, V204B, V206A,
V207B, V308A, V307A7 V305, V310B
V201, V202, V301, V302, V501, V502
V201, V202, V301, V302, V501, V502,
V2 06

V103A, bias V208A, V507

Bias
V505, V506
77503, V504

Bias

V505, bias V506

TABLE 5.6

TABLE OF D-C OUTPUTS

at

(Measured

S0602)

Volts

RlOl
R103
R104
R105
R106
R107
R108
R109
RllO
R112
R113
R114
R115
R116
R117
R118
R119
R120
R121

TYPE

PARTS LIST

1391-8

PULSE, SWEEP, AND TIME-DELAY GENERATOR

GR No.

(NOTE

A)

REC -20BF

971-410

POSW -3

REC

-

30BF
REC-41BF
REC-41BF
REC-20BF
REC-20BF
REC-41BF
REC-20BF
REC-20BF
REC-41BF
REC-3OBF
REC-20BF
REPO-43
REC-20BF
REC-30BF
REC-2OBF

REC -20BF

POS.

GOING

S/O/ ENGRAVING

Dc

.

NEG.

AC

GOING

ClOl

C102

C103
C104
C105
C106
C107
C108
C109
CllO
Clll
C112

BLlOl
Dl01

Dl02

Dl 03

DL101
FlOl

LlOl
PLlOl
SlOl
VlOl
v102
V103
V104

BLOWER

CRYSTAL DIODE
CRYSTAL DIODE
CRYSTAL DIODE
DELAY LINE,

O.2psec
SNAP CONTROL, Thermo
AIR CHOKE, 50ph

PLUG

SWITCH, Rotary

TUBE

TUBE

TUBE

TUBE

COC-21(M50)
COT-23
COM -2OB
COC - 63
COM-20B
COM-20B
COM-20B
COL -71
COC

-

63
COW-25
COL-71
COC-1

@SCREW DRIVER ADJUSTMEN7
RESISTORS
RESISTANCE IN OHMS UNLESS

CAPACITANCE VALUES

MICROFARADS, LESS

UNLESS

HEATER CABLE CONNECTIONS SHOWN IN FIGURE

TP USED.' /Of, 102, I03

//2

WATT UNLESS OTHERWISE SPECIFIED

K

=

I000

OHMS

OTMRWISE SPEC/FIED

THAN

M

ONE AND OVER IN MICRO

ONE

07HERWISE SPECIFIED

*

I

MEGOHM

IN MICRO FARADS,

5.5b.

I

BLOCK

SCHMITT

CIRCU/ T

D/AGRAM

-

FORMING PULSE
CIRCUIT

DIRECT TRIGGER

I

4

-

TO DELAY CIRCUIT

OUTPVT AMPLIFIER

CATHODE FOLLOWER

a

1

*

@INC.

DIRECT

OUT

explanation

For

of

NOTES, refer to

page

42.

Figure

5.1.

Schematic Diagram for Input Trigger Generator Circuits.

GENERAL RADIO COMPANY

PARTS LIST

1/2

w

1/24

w

I

W

1

w

1/2 w
1/2

w

1/2

w

1/2

w

1/2 w
1/2 w
1/2

w

2

w

1

w

1/2W
1/2 w
1/2

w

1/2

w

1/2

W

1/2

W

1/2

w

1/2

W

1/2

W

1

w

2

w

5 w

1/2

W

2

W

1/2

W

1

w

1/2

w

1/24

w

1/2

w

1/2

w

1/2

w

1

w

w

1/2

2 w

w

1/2
1/2

w

1/2

w

1/2

w

1

w

GR No.

(NOTE

REC-20BF
REC-2OBF
REC-30BF
REC-30BF
REF-70
REF-70
REF-70
REF-70
REC-2OBF
REC-20BF
REC-20BF
REC-41BF
REC-3OBF

REC-20BF

REC
REC-20BF
REC-20BF
REF-70

REF-70

REF-70

REF-70
REF-75
REF-2-2

POSC-

POSC-11

POSC-

POSC-11

POSC-11

POSC­REC-41BF

REPO-43

POSW -3

1391-42

POSW-3

REF-70

REC-41BF

REF-70

REC-30BF

REC-2OBF

REC-20BF

REC-20BF

REC-20BF

REC-20BF

REC-30BF

POSW-3

REC-2OBF

REC-41BF

REC-20BF

973
REC-20BF
POSC­REC-30BF
REC-2OBF
REC-30BF

A)

-20BF

11

11

11

-N

11

k259

R260
R261

R2 62
R2 63
R264
R265
R266
R2 67
R268

n

aR269

a

R270
R271

5

R272

5

m

R273
R274
R275
R276

5;

W

R277
R278
R279
R280
R281
R282
R283
R284
R2 85
R286
R287
R288
R289
R290

C201

C202

C203

fiC204

C205

C206

gC207

--

C208
C209

2

C219

0

C220

k

C221

2

C222

3

C223

u

C224

C225
C226
C227
C229
C230

220

100
330

6.8 k

1

100 k

10 k

100

1

47
47 k

180 k

5.1 k

1

27 k
27 k
33 k +'5% 1/2 w

10 k

220 k

10
18

100

1

560

62 k

1200

1.8k

(Note

F)
100
100 k
100

100 k

100
100

22
22

47

0.001pf
O.O1p.f

0.01p.f

O.01pf

0.0047pf

0.01pf

0.47pf

7-45

470

0.0047p.f

0.047pf

0.47p.f

0.01pf

3.3

47

25% 1/2w

k

+

5%

+

5% 1/2

+lwo

+

k

5 1/2 w

+lvo

+

5%

+

5% 1/2 w

k +5%

+

5% 1/2 w

+5% 1/2w

+

5% 1/2 w

+

5% 1/2 w

+

k

k

M

k

M

k

5% 1/2 w

f

5%

+

5%

k

5% 5w

+

5% 1/2 w

+l%

+

5% 1/2 w

+lvo

+

5% 1/2 w

+

5% 1/2 w
f:5% 1/2w
+5% 1/2w

f

5% 1/2w

+

5% 1/2 w

+

5%

+

5% 1/2 w

+

5%

5% 1/2 w

flVo

+la

+la

+1%

+lo%

+1%

+lvo

+loo-Vo

+loo-vo

f

lvo

+loo-%

f

lvo

+

2% 500dcwv

+

2% 5OWcwv

+

2% 150d~~v

+

2% 150dcwv

+loo-vo

20.5ppf 500dcwv

+lo%

1/2 w

w

2 w

lw

1

w

I

w

1

w

1

w

1

w

1/2 w
1/2 w

500dcwv
50Wcwv
500dcwv
500dcwv
5OWcwv
300dcwv
hOOdcwv
~OWCWV
50Wcwv
200dcwv
500d~wv
lOOdcwv

500dcwv
5OOdcwv

GR No.

(NOTE

-&CC-~OBF

REC-20BF
REC-20BF
REC-41BF
REC-2OBF
REC-30BF

973-N
REC-2OBF
REC-30BF
REC-20BF
REC-20BF

REC-2OBF

REC-20BF

REC-20BF

REC-30BF

REC-30BF

REC-20BF

REPO-43

REC-2OBF

REC-30BF

REC-20BF

REC-30BF

REC-2OBF

REC-20BF

REC-20BF

REC-20BF

REC-20BF
REC-20BF
REC-20BF
REC-20BF
REC-20BF

REC-2OBF
COC-21

COC-21
COC-21(N750)

COC-21(N750)

COC-21(N750)

COM-2OB

COL-71
COC-63

COC-63

COW-16

COC-63

COW-17

COT- 12

COM-20E

COM-35E

ZCOP-8
ZCOP-6-2

COC-63
COC-2

COM-20B

A)

l(N750)

TYPE

1391-B

PULSE, SWEEP, AND TIME-DELAY GENERATOR

r

h

U

w

m

8

b

G

3

-4

C231
C232
C233
C234
C235
C236

C238
C239
C240
C241
C242
C243

C244
C245
C246
C247

C248

(3249

C250

C251
C252

C253

C254

C255

0.22pf

0.0047pf

0.22pf

330

0.001pf

0.lp.f

0.001P

47

0.047pf

470

10 50. Sppf 500dcwv

0.01pf

0.01pf +100-0qr, 500dcwv

0.001pf

470

47

0.001pf 21% 300dcwv

100 5OOdcwv

0.01pf

47

0.001pf 300dcwv

100

22

470

51v0

+lwo

flwo

+lwo

f

2% 3OOdcwv

flwo

f

lvo

tlwo

51%

+lwo

+lwo

51%

1

51%

+lwo

+lo%

1

+lo%

+lo%

1i)Odc~v
600dcwv
200dcwv
500dcwv

4OOdcwv
500d~v

5OOdcwv
100dcmv
500dcwv

60Odcwv
300dc~v

500dcwv
5Oodcwv

60odcwv
500dcwv

500dcwv
50Od~wv
5OOdcwv

GR No.'

(NOTE A)

COW-17
COL-71

COW-16
COM-20B
COM-20E
COW-25

COM-2OB
COC-2 1 (N750)
COW-17
COM-20B
COC-2
COL-71
COC-63
COM-BOB
COM-20B
~0C-21(N750)
COM-20B
COM-20B
COL-71
COC-21(N750)
COM-20B
COC-21

COC-21
COM-20B

1

(N750)

(N750)

D201 CRYSTAL DIODE
D202 CRYSTAL DIODE
D203 CRYSTAL DIODE
D204 CRYSTAL DIODE
D205 CRYSTAL DIODE

m

L201
I202 AIR CHOKE, lOOph

2

S201 SWITCH
S202 SWITCH

4

S203 SWITCH
T201 TRANSFORMER

u

,

I

V201 TUBE
V202 TUBE

V203 TUBE
V204
V205

V206
V207

V208
V209 TUBE

AIR

CHOKE, 50

TUBE
TUBE
TUBE
TUBE
TUBE

ph

GR No.

(NOTE A)

1N54-A

1N54-A
IN118
1N34-A
IN118

CHA-3-2
CHA-3-3
SWRW-113
SWT-8
SWT-320

1391-44

6485
6485
6AN5
6AU8A

12AX7
5965

6U8
6U8
NE-51

i

to

For explanation of NOTES, refer

DIRECT TRIGGER FROM DELAY CONTROL SWEEP RESET TRIGGER

TRIGGER

TO

SWEEP CIRCUIT

COINCIOENCE

DRIVE

+

@

&

BISTABLE GATE GENERA TOR

MONOSTABLE GATE GENERATOR

o

-

COINCIDENCE

PULSE INVERTER

-

BLOCK

DIAGRAM

page 42.

AMPLITUDE COMPARATOR

DELAY SYNC. PANEL

AMPLIFIER

DEL. SYNC. AMPLIFIER

B

CATHODE FBLLOWER

INDICATOR

r

Block Diagram for Delay Circuits.

I

0

DELAYED

SYNC.

FE

-

,

TO V-3OI
SWEEP CONTROL GATE

+300 REG.
P/N2, Pi-401

+

300

PIN 4, PL-401

fA

T

RANGE

3055)

REVSTANCE

CAPACITANCE

K

/N

=

OHMS UNLESS OTHERW/SE SP€C/F/ED

/000

OHMS

VALUES ONE AND OVER

FARADS, LESS THAN ONE

OTHERW/SE SPECIFIED.

M

=

/

MEGOHM

/N MICRO MICRO-

/N

M/CROFA /?ADS, UNLESS

@

SCREW DR/VER ADJUSTMENT

HEATER CABLE CONNECTIONS

SHOWN IN FIGURE

5.5b.

Figure

5.2.

Schematic Diagram

for

Delay Circuits.

I-

l

urn

/\

l

SEC

GENERAL RADIO COMPANY

GR No.

(NOTE
REC-20BF R358

REC-20BF R359
RE

C-3OBF R360
REC-3OBF
REF-70
REF

-

REF -70
REF

-

REC-20BF
REC-2OBF R367
REC-20BF
REC-41BF R369
REC-30BF
REC-20BF R371
REC-ZOBF R372
REC-20BF R373
REC-20BF R374

973-N
REC-41BF
REC-2OBF

REC-20BF
REC-20BF

REC-2 OBF
REC-20BF

REC-20BF

POSC
POSC­POSC­POSC-11
POSC­POSC-

REC-41BF
RE C-41BF
REC-20BF
REC-20BF

1391-40

POSW-3
REC-20BF
REC-30BF
REC-20BF
REC-20BF
REC-20BF
REC-20BF
REC-2OBF
REC-41BF
REC-41BF

1/2

w

REC-20BF

2

w

REC-41BF

Paw-3

1 w REC-3OBF

PARTS

LIST

A)

3

R361

rn

R362

70 R363

2;

R364

-

70

-

11

11

11

11

11

2

d

R365
R366

R368
R370

100
100

2 2
2 2
47

0.001

0.Olpf

3-12

430

0.0047pf

0.047pf

0.47pf

0.1 pf

1
1

4

7

30

0.OOlclf

220

47
10
47

0.1

1

1

1

16

100

+lvo

+lvo
+lvo

+lvo

+

10%

pf

21% 300dcwv

+lWo

clf

pf

clf

pf

clf

~f

wf

Pf

CRY

STAL-DIODE
CRYSTAL DIODE
CRYSTAL DIODE

(NOTE A)

REC-20BF
REC-20BF
REC-20BF
REC-41BF
REC-20BF
REC-30BF
REC-3OBF
REC-20BF
REC-20BF
REC-20BF
REC-20BF
REC-20BF
REC-20BF
REC-20BF
REC-41BF
REC-20BF
REC-20BF

500dcwv
500dc~~
500dcwv
500dcwv

dcwv

600dcwv

c0c-2

COC-21

c0c-2

c0c-2

c0c-2

COM-20B
COL-71
COT-23
COM-20E
COM-3%
ZCOP-8
ZCOP-6-2
COW-25
COW-25
COW-25

c0c-2

COE- 53
COM-2OB
COM-2OB
COM-20B
~0~-21(~750)1
COM-20B

COC-63

COW- 17

COW-25
COW-25

c0e-4

c0c-2

1N54-A
HD6008

GR

No.

1

l(N750)
l(N750)
l(N750)

l(N750)

1

I

'or explanation of

II

NOTES,

1

refer to

I

page

SWITCH

42.

SWRW-80
SWRW-81

V303
V304

TUBE

TUBE

GR

No.

(NOTE

6AN5

12BH7

Figure

5.3.

GR No.

A)

V308

Schematic Diagram for Sweep Generator Circuits.

TUBE

(NOTE

A)

GR No.

(NOTE

A)

p-pipq

TUBE NE-51

POS.

GATE

@

NEG.

GATE

@

TR166ER

FROM

4

S-PO3

Block

Diagram for Sweep Generator Circuits.

6A TE

C.

F.

-

-

SWEEP SWEEP

CONTROL

BISTABLE

+

GATE

I

SWEEP

1

INVERTER

4

C.

F.

+

SWEEP

YON1 TOR

I-0

-

PAML

w

INDICAtUR

TlMIM OlRCUl?S

TO PULSE

@

SCREW DRIVER ADJUSTMENT

0

PANEL ADJUSTMENT

RESISTORS

WISE

RESISTANCE IN OMS UNLESS OTHER

WISE SPEC/F/ED.

K=

CAPACITANCE VALUES ONE AND

IN MICR OM/CROFARADS,

THAN ONE /N MICROFARADS UNLESS

OTHER

*

HEATER CABLE CONNECTIONS SHOWN IN FIGURE

If2

SPECIN

1000 OHMS

WATT UNLESS OTHER-

ED

W/SE SP ECIFIED

M=

I

MEGOHM

LESS

OVER

5.5b.

GENERAL RADIO COMPANY

R401
R402
R403
R404
R405
R406
R407
R408
R409

R410
R411
R412
R413
R414
R415
R416
R417

-

R418
R419

OR420

5

R421
R422

2

R423

0

R424
R425
R426

2

R427
R428
R429
R430
R433
R434
R435
R436
R437
R438
R439
R440
R441
R442
R443
R444
R445

PART NO. (NOTE A)

560
560

10k 55% 1391-210
10k 55% 1391-210
24k
24k
10k +lo% POSW -3
10k 210% POSW - 3
10k +5% 1391 -210
10k

2.5k +lo% POSW - 3

2.5k +lo% POSW-3
12k
30k +l%
18k +5%

6.8k
47k

330k

27k

1,2k

18k

1M

1M
33k
27

150k

33

3.3M *5%

3.3M
33k
12k
30k
18k

6.8k
47k

330k

27k

1,2k

18k

IM
1M

10k

36k

*

5%

5

5%

+5% 2~ REC-41BF

+5% 2~ REC-41BF

+5%

51%

+5%
+s%

*

5%

*5%

+lo%

+5%
+5%
+5%
55%
2 5%
+5%

+

5%

+5%
+5%

51%
51%

25%

+5%
+5%
25%
55%
55%

55%

+5%
+5%

*

5%

+5%

1

/2w REC-20BF

1

/2w REC-20BF

1391 -210

1

/2w REF-70

1

/2w REF-70

1

/2w

IW

1

w

1

/2w REC-20BF

1

/2w REC-20BF

1/2w REC-20BF

1

/2w REC-20BF

1

/2w REC-20BF

1

/2w REC-20BF

IW

1

/2w REC-20BF

1

/2w REC-2OBF

1

/2w REC-20BF

1

/%

1

/2w REC-20BF

IW

1

/2w REF-70

1

/2w REF-70

1

/2w REC-20BF

IW

IW

1

/2w REC-20BF

1

/2w REC-20BF

1

/2w REC-2OBF

1

/2w REC-2OBF

1

/2w REC-2OBF

1

/2w REC-20BF
2w REC-41BF

1

/2w REC-2OBF

REC-2OBF
REC-30BF
REC-30BF

REC-30BF

REC-2OBF
REC-SOBF

REC-30BF
REC-30BF

PARTS

W

&

3

m

3

P

3

2

3

LIST

R446
R447
R448

C401
C402

C403

C404
C405
C406
C407
C408
C409
(3410
C411
C412
C413
C414
C415
C416

C417

C418
C419
C420
C421

C422

D401
D402

L401

L411
PL401

S401

T401

T402

V401

V402

V403

V404

V405

V406

PART NO. (NOTE A)

1

150k

33
10k

33

10 +0.5ppf
100
100

0,Olpf +loo-0%

0.01pf
O.Ol\Jf +loo-0% 300dcwv COC-63

10

0.Olpf +loo-0% 500dcwv COC-63

0.01pf +loo-0% 1000dcwv COC-63
33
10

100
100

0.01p.f +loo-0% 500dcwv COC-63

0.01pf +loo-0% 500dcwv

7-45 510%

22
10

0.01p.f +loo-0% 100Odcwv
10
10 +O. 5ppf 5OOdcwv COC-21(N750)

CRYSTAL DIODE
CRYSTAL DIODE
CHOKE
CHOKE 500p.h
PLUG
SWITCH
TRANSFORMER
TRANSFORMER
TUBE
TUBE
TUBE
TUBE
TUBE
TUBE

+5%

*

5%

+5% 2~

+lo%

510% 500dcwv COM-20B

+lo%

+loo-0%
+0.5ppf 500dcwv COC-21(N750)

+lo%

+O.

5ppf 500dcwv COC-21(N750)

+lo%

+lo%

+lo%

k0.5pp.f 500dcwv

k0.5pp.f 500dcwv COC-21(N750)

500$

/2w REC-20BF

1

/2w REC-2OBF

500dcwv COC- 21(N750)
500dcwv COC-21(N750)

300dcwv COM-20B
500dcwv
500dcwv COC-63

500dcwv COC-21(N750)
500dcwv COM-2OB

5OOdcwv COM-2OB

500dcwv COT-12
500dcwv COM-2OB

REC-41BF

COC-63

COG-63

COC-21(N750)
COC-63

1N34-A
1N34-A
CHA-597A
CHA-597A
CDMP-11-12

SWRW

-

176
1391-45
1391-45
12AX7
12AX7
6485 or 6AH6WA
6485 or 6AH6WA
6485

or

6AH6WA

6485

or

6AH6WA

For

explanation of

NOTES,

refer to page

42.

SWEEP FROM START

V307

.)

STOP

@

@

START TRIG

TO

0502

v501

STOP TRIG.

START TRIG.
TO

DSOI,SO3

PULSE START-STOP TRIGGERS

S401 ENGRAVING

+

RESISMRS M WATT UNLESS OTHERWISE SPECIFIED
RESISTANCEIN OHMS UNLESS OTHERWISE SPECIFIED

K=

1000 OHMS

CAPACITANCE

LESS THAN ONE IN MICROFARADS, UMESS OTHERWISSE

YALLIFS ONE AND OVER IN MICRO MICROFARADS

M

=

-

I

MEW

---

SPECIF~E~

0

PANEL CONTROL

@SCREW

*

Figure

lRlvER

HEATER CABLE CONNECTIONS SHOWN

5.4.

Schematic Diagram for Pulse-Timing Circuits.

ADJUSTMENT

IN

FIGURE

6485/bAHbWA

5

5b

GENERAL RADIO COMPANY

PARTS LIST

-

,

-

2

o

2

t;

*

R501
R502
R503
R504
R505
R506
R507
R508

R509

R510
R511
R512
R513
R514
R515
R516
R517
R518
R519

R520

R521
R522
R523
R524
R525

R526

R527

R528

R529
R530
R531
R532
R533
R534
R535
R536
R537
R538
R539
R540
R541
R542
R543
R544
R545
R546
R547
R548

R549

R550
R551

R552
R553
R554
R555
R556
R557
R558
R559
R560
R561

PART NO. (NOTE A)

620
620 +5% 1/2w REC-20BF

180k

180k 21% 1/2w REF-70

100
100
300 2 w REC-41BF

6.8k +5%

51

2.7k +5%

2.7k
51
51

2.4k

330k
330k
240k

1.8M

750
620k
620k

2.7k +5% 1/2w REC-2OBF

2.7k +5% REC-POBF
51 25% 1/2w REC-20BF
51

120 25%
120
120 2 5%
120 f5%
100 25% 1/2w REC-2OBF
100 +5%

51
51 +5%
51 5~5%

51 +5%

600

5k

270k

1.5M

130k

130k

5.lk 25% 2

6.8k
300 25% 2
300

51
51
51
22
22
22
22
56

56
470
470

680 1/2w REC-20BF
750

lk

1.5k

5 1/2w REC-2OBF

+1%

*

5% 1/2w REC-20BF

+5% 1/2w REC-2OBF

15%

*

5%

+5%

+5%
+5% 1/2w
+5%
25%

1
il%

fl%

+1%

+5% 10 w REPO-44
+I%

*I%

Its%

*

5% 2 w REC-41BF

5%

*

5% 5 w

*

5%

1 1/%

*l%

1
+1%

*

5% 2

k

5% 2

2

5% 2 w REC-41BF
+5% 2
*5% 2

+

5%
+5%

+

5%

+

5%

2

5% 2
*5% 2

+5% 10 w REPO-42-

+5% 1/2~
+5% 1/2~
*5%

1/2w REF-70

2

w

REC-41BF 300

1

w

1/2w REC-2OBF

11%

1/2w REC-2OBF

1/2w REC-2OBF

1/2w REF-70

1/%

1/2w REF-70

1/2w REF-70

11%

1/2w REC-2OBF-

l/%

11%
1/2~ REC-20BF

1/2w REF-70
1/2w
1/2w

10 w REPO-42-:

1/2w REC-2OBF

For explanation

REC-30BF
REC-20BF
REC-2OBF

2

w

REC-41BF
REF-70

1

w

REF-75

1

w

REF-75

REC-POBF

2

W

REC-41BF

2 w

REC-41BF

2 w REC-41BF

REC-POBF
REC-2OBF

REG-20BF
REPO-42

5 w REPO-42

REF-70
REF-70

REF-70

w

REC-41BF

w

REC-41BF

w

REC-41BF

w

REC-41BF

w

REC-41BF

w

REC-41BF

1

w

REC-30BF

1

w REC-30BF

1

w REC-30BF

1

w REC-30BF

w

REC-41BF

w

REC-41BF

REC-20BF
REC-2OBF

of

R562
R563
R564

R565

R566
R567
R568
R569

-

R570
R571
R572
R573
R574
R575
R576
R577
R578
R579
R580
R581
R582

.

,

C501

C502

0

C503
C504
C505
C507

8

C508
C509

2

C510

~4

C511

3

D501
D502
D503

L50l
L502
L503
L504
L505
L506
L507

L508
L509

L510

LSll

L512

L513

L514
L515

S501
S502

'

V501
V502
V503

8

V506
V507

NOTES, refer to page 42.

2.2k

2.7k
3k

3.6k

3.9k

8.2k

10k *5% 5
10k *5% 5

7.5k +5% 5

6.2k 5

5.6k *5%

13k

13k

13k
100
100

1.1M

1.3M

22

5.lk

4.7k

O.Olpf +loo-0% 500dcwv COC-63

0.01pf +loo-0% 500dcwv COC-63

0.01pf +loo-0% 500dcwv COC-63

0.01yf +loo-0% 500dcwv COC-63
O.1p.f

0.01pf +loo-0% 50Odcwv COC-63

0.01yf +loo-0% 500dcwv COC-63

0.01pf +loo-0% 500dcwv COC-63

0.47yf

0.01pf +loo-0% 500dcwv COC-63
CRYSTAL DIODE

CRYSTAL DIODE IN191
CRYSTAL DIODE 1N191

6.8 ph +lo%

6.8
10
10
10

10

4.7

4.7

1
1

0.33

0.33
15

4.7

4.7
SWITCH, Rotary SWRW-83
SWITCH, Rotary SWRW-177

*lo%

+lo%

ph

2

ph

f10%

ph

+lo%

ph

+lo% CHM-1

ph

+lo%

ph

210% CHM-1

ph

210% CHM-1

ph

+lo%

ph

+lo%

ph

+lo%

ph

+lo%

ph

+lo%

ph

flO%

ph +lo%

5687
12AX7
6AV5GA

6AV5GA
6 AV5GA
6AV5GA

6550

PART NO. (NOTE A)

+5%

25%
k5%

*5% 1/2w

f

5% 1/2w

*5% 5 w

t5'
*5% 2

A

5% 2

*5% 2 w REC-41BF
+5%

+5%
+5% 1/2w
f5% 1/2w

+5%
+5% 1/2w
+5%

10%

1/2w REC-20BF
1/2w REC-2OBF

1/2w REC-20BF

1/%

1/2w REC-20BF

1/2w REC-20BF
1/2w REC-20BF

400dcwv COW-25

200dcwv COW-16

V508

V

V510
V511
V512
V513
V514

REC-20BF
REC-2OBF
REPO-43

w

REPO-43

w

REPO-43

w

REPO-43

w

REPO-43

5 w REPO-43

w

REC-41BF

w

REC-41BF
REC-2OBF

REC-20BF
REC-2OBF

REC-2OBF

IN191

CHM-

CHM-1

CHM-1
CHM-1

CHM-1

CHM-1

CHM-1
CHM-1
CHM-1
CHM-1
CHM-1
CHM-1

509

1

6550
12AX7
OA2
12BH7

NE-2

NE-2
NE-2

38

Block Diagram for Pulse-&

V405

START TRIG.

V406

STOP

TRIG. GEN.-

Inerator Circuits.

GE~

PULSE

CONTROL

B/STA8LE

rp-502

0

-

c-c

-

AMPL If-IEff

-

c

AMPL //VIER DRIVER AMPLIFIER

POWER

.3

4*

GY-RD

-

Figure

EL-RD

EL

WH-RO

YE-6Y

5.5b.

5.

6.

7*

J\

Detail of Plugs for Power Supply.

8,

C

/

*

b

-

4

GENERAL RADIO COMPANY

-

$

--

2

0

5

m

A

U

W

Z

w

8

b

3

2

4

R601
R602
R603
R634
R605
R606
R607
R608
R609
R610
R611
R612
R613
R614
R615
R616
R617
R618
R619
R620
R621
R622
R623
R624
R625
R626
R627
R628
R629
R630

R631
R632
R633

R634

C601
C602
C603A
C603B

C603C

C604A

C604B

C604C

C605A

C605B

C605C

C606A

C606B

C606C

C607A

C607B

C607C

C608A

C608B

C608C

C609A

C609B

C609C

C610A

C6lOB

C610C

1M 55% 1/2w
1M
1M
1M

180 k f10%

33k

5 k 210%

220 k

5.lk
10k f5% 2w
91
lOk
75k

100

15 k 510% 2
10 k 210%

100
500

2.7 k

82k 25% 1/2w

100
100
100
100
100
100
100
100

15
33 k 510% 2
22
16

22
15

100 15Odcwv
100 150dcwv

30

::

30

z:

30

;:

30

30

30

93;

30

z:

30

z:

k

}

}

}
}

}

}

f5% 1/2w

f

5% 1/2w

*5% 1/2w
210% 2~

f

5% 112 w

f

5% lw

f

1%

1

w

1/2w

*lo%

f

1%

f

t

1/2w

5%

1/2w

w

5% low

*lo%

f

5% 10

2 5%

*

5% 1/2w

*

5%

+

5% 1/2w

f

5% 1/2w

f

5% 1/2w

f

5% 1/2w

f

5% 1/2w

*lo%

*lo%

f10% 40w

*lo%

flog

w

1/2w
1/2w

1/2~

w

10 w
10 w

10

w

300 dcwv

300 dcwv

300

dcwv

300

dcwv

300

dcwv

300 dcwv

300 dcwv

300 dcwv

PARTS

PART NO.

(NOTE A)

REC-2OBF
REC-2OBF
REC-20BF
REC-2OBF
REC-3OBF
REC-41BF
POSW -3
REC-2OBF
REC-30BF
REC-41BF
REF -70
POSW -3
REF -70
REC -20BF
REC-41BF
POSW -3
REPO-22
POSW -3
REPO-22
REC

-2OBF
REC-2OBF
REC-2OBF
REC-2OBF
REC - 2OBF
REC-2OBF
REC-2OBF
REC-2OBF
REC-20BF
REW-3C
REC-41BF
REPO-22
REPO-2lP
REPO-22
REPO-22

COE-45
COE-45

COE-52

COE-52

COE-52

COE-52

COE-52

COE-52

COE-52

COE-52

LIST

C611A
C611B
C611C
C612A
C612B
C612C
C613A
C613B
C613C
C614A
C614B
C614C
C615A
C615B
C615C
C616A
C616B
C616C
C617A
C617B
C618
C619A
C619B
C620
C623
C624
C625A
C625B
C625C

F601
F601
F602
F602
L605

L606
L607
L608
L609
P601

PL601
RX601
RX602

RX603

RX604

RX605

RX606

RX607

RX608
RX609
RX610
S601
T601

V601

V602
V603

z:

}

30

::

}

30

z!

]

25

i:

}

30

z:

}

30

z:

}

30
25

0.047

i:

0.047 f10% 400

0.01 210% 600

0.01

::

30

FUSE, 4 amp, Slo-Blo Type

3AG (for 115-v input)

FUSE, 2 amp, Slo-Blo Type

3AG
FUSE, 4 amp, Slo-Blo Type
3AG (for
FUSE, 2 amp, Slo-Blo
3AG (for 230-v input)
CHOKE
CHOKE
CHOKE
CHOKE
CHOKE
PILOT LAMP, 6.3

Mazda

PLUG, Input
RECTIFIER
RECTIFIER
RECTIFIER
RECTIFIER
RECTIFIER
RECTIFIER
RECTIFIER
RECTIFIER
RECTIFIER
RECTIFIER
SWITCH, dpst
TRANSFORMER
TUBE
TUBE
TUBE

+lo%

}

*lo%

}

(for 230-v input)

11

#44

300 dcwv

300 dcwv

45Odcwv

300 dm

300dcwv

300 dcwv

200
200 dcwv

450dcwv

600
300

5-v input)

V,

dcwv

dm

dcwv

~CWV

dcwv

Type

PART NO.
(NOTE A)

COE-52

COE-52

COE-10

COE-52

COE-52

COE-52

COE-51

COW-16
COE-5
COW-25

COL-71
COL-71

COE-52

FUF-1
FUF-1

FUF-1

FUF-1

485-406
485-456
485-406
485-406
485-406

2LAP-939
ZCDPP- 10

IN1083

IN1083
IN1084
IN1084

IN1084

1N10841
1N1083
IN1083
IN1084
IN1084
SWT-333NP

565-419
6AS7 -G

6AK5
OD3

For explanation of NOTES, refer to page 42.

FOR 115V OPERATION CONNECT

NOTE FOR T-601

FOR 230V OPERATION CONNECT

91

#2

TO

TO

W3

#3

8

W?

TO

#4

RESISTORS
RESISTANCE

K=l000 OHMS M= I MEGOHM

CAPACITANCE VALUES ONE AND OVER IN MICRO

MICROFARADS, LESS
UNLESS

IY2

WATT UNLESS OTHERWISE SPEC/F/ED

IN

WMS UNLESS OTHERWIE SPECIFIED

WAN ONE IN MICROFARADS,

0

THER

WISE SPECIF /ED.

@

SCREWDRIVER, ADJUSTMENT

*

S'CTlON 90ufs

*

*A SEGTION 50~f,

***A

El

6

SECTIONS lOp

A

8

8

SECTIONS 25~f - ZOO WV

6

dl

8

C

SECTIONS 3O!f - 3OOWv

C SECTIONS 25~f - 450

f

-

450 WV

WV

Figure

5.6.

Schematic qiagram for Type

1391-6

Power Supply.

NOTES

(A) Type

designations for resistors and capacitors are as follows:

Capacitors

COC-ceramic
COL-oil
COM-mica
COP-polystyrene

Resistors

REC -composition
REF -film
RE PO -power

POSC -variable composition
POSW -variable wire -wound

(B)

All resistances are in ohms unless otherwise indicated by k

(kilohms) or

M

(megohms).

(C) Capacitances are in micromicrofarads except as otherwise
indicated by

(D)

Sections A,

(E)

Capacitances are in microfarads.

(F)

Value determined in General Radio laboratory.

pf

(microfarads).

B,

C, are

90,

30,

30

pf, respectively.

POWER
TRANS.

I

Elementary Schematic Diagram for Type 1391-P2 Power Supply.

V603

+

+

450

300

REG.

GENERAL RADIO COMPANY

Figure 5.7. Test Waveforms

1.

INPUT CIRCUITS 100 kc 2psec/cm

A. INPUT SIGNAL 5v/cm

B.

TPlOl (INPUT AMP) 20v/cm
C. TP102 (DIR TRIG SCHMITT) 5Ov/cm
D. TP103 (DIR TRlG GEN) 20v/cm

2. INPUT CIRCUITS
A. DIRECT TRlG

B.

DIR SYNC PULSE 50v/cm

3.

DELAY CIRCUITS 100 kc 2psec/cm, DELAY SET FOR 4psec.

A. DIRECT TRlG lOv/cm

B.

TP201 (POS DEL GATE) 50v/cm

C. TP202 (DEL SWEEP) 50v/cm
D. TP203 (DEL RESET PULSE) 50v/cm

E.

TP203 (DEL RESET PULSE) 50v/cm

F.

TP204 (COINC GATE) 50v/cm (3psec)
G. TP205 (DELAY TRIG INV) 5v/cm
H. DELAYED SYNC 100v/cm

5v/cm (8-ppf probe)

4. SWEEP CIRCUITS 100 kc 6psec/cm
A. SWEEP TRIGGER (DELAYED 4psec) lOv/cm

B.

GRID

(7)

V305 50v/cm
C. POS GATE 50v/cm
D. NEG GATE 50v/cm

E. TP301
F.

TP302, 303 (SWP CF) 100v/cm

G. TP304 (SWP RESET AMP COMP) 5v/cm

H. TP305 (SWP RESET TRIG) 20v/cm

(SWP

GEN) 100v/crn

TYPE

1391-B

PULSE, SWEEP, AND TIME-DELAY GENERATOR

6.

PULSE GENERATOR

A. STOP PULSE

6.

START PULSE

C.

V50l PLATE (PIN 9)
V50l PLATE (PIN 1)

D.

TP501 (MV NEG) 20v/cm

E.

F.

TP503 (DRIVER GRlD POS) 50v/cm
G. TP502 (MV POS) 20v/cm
H.

TP504 (DRIVER GRID NEG) 50v/cm

1.

TP505 (DRIVER PLATE NEG) 20v/cm

J.

POS PULSE (94R) 20v/cm

K.

TP506 (DRIVER PLATE POS) 20v/cm

L.

NEG PULSE (94R) 20v/cm

GENERAL

RADIO

COMPANY

TYPE

1391-8

PULSE, SWEEP, AND TIME-DELAY GENERATOR

GENERAL RADIO COMPANY

TYPE

1391-8

PULSE, SWEEP, AND TIME-DELAY GENERATOR

CI

QD

0

-

0

Ic

Ok

"=-

-

-

KLZ

w

0

0

t

l

R103 CIO2 R108

R104

Figure

5.1

1.

Left Side Interior View.

GENERAL RADIO COMPANY

Figure

5.12.

Right

Side

Interior View.

TYPE

1391-8

PULSE, SWEEP, AND TIME-DELAY GENERATOR

Figure

5.13.

Top Interior View of Power Supply.

GENERAL RADIO COMPANY

Figure

Bottom Interior View of Power

5.14.

Supply.