INSTRUCTION MANUAL
MODEL 421
LOG N PERIOD AMPLIFIER
WARRANTY
We warrant each of our products to be free
from defects in material and workmanship. Our
obligation under this warranty is to repair or
replace any instrument or part thereof (except
tubes and batteries) which, within’ a year after
shipment, proves defective upon examination.
We will pay domestic surface freight costs.
To exercise this warranty, call your local
field representative or the factory, DDD 216.
795-2666. You will be given assistance and
shipping instructions.
REPAIRS AND RECALIBRATION
Keithley Instruments maintains a complete re-
pair service and standards laboratory in Cleve-
land, and has an authorized field repair
facility in Los Angeles.
To insure prompt repair or recalibration serv-
ice, please contact your local field representative or the plant directly before returning the
instrument.
Estimates for repairs, normal recalibration?,,
and calibrations traceable to the National Bureau
of Standards are available upon request.
m)DEL 421 IOG n PERIOD AMPLIFIER
!lABLE OF CONTENTS
Section
1.
GEBERAT, DWCRIPJ!ION. ............
l-l.
l-2. Features................l- 1
1-3.
l-4. Equipment Shipped. ...........
2.
OPJSRATION.
2-l. Front Panel Controls ..........
2-2.
2-3.
2-4. Operating Procedures ..........
z-2. mmping.................2- 2
CIRCUIT DESCRIFTION. .............
3.
y-1.
;:;:
3-4.
General. ...............
Specifications
.............
..................
Rear Chassis Controls and Terminals.
Input Connection
- .
Recording.
General. ................
Log n Amplifier Circuit.
Period Circuit
Power Supply
...............
............
........
.............
..............
Page
.1-l
.1-l
1-2
1-3
2-1
2-1
.. 2-1
2-2
2-2
2-3
3-l
3-l
3-1
3-2
3-3
4.
WU'iTENANCE
4-2. Electrometer Tubes
4-6.
4-7. Calibration of Period Circuit. .....
REPLACEABLEPARTS .............
5.
5-2. How to Order Parts ...........
Change Notice
*Yellow Change Notice sheet is included only for instru-
ment modifications affecting the Instruction Manual.
Calibration of Log n Amplifier
Model 421 Replaceable Parts List
Schematic Diagrem
..................
...........
16298D
........ 5-y
.....
..5- 1
.... 5-2
4-l
k-1
4-1
4-Z
5-l
last
page
0563
vo.3
i
1-l
GENERALDF!SCRIPmOM
MODEL 4211~~)
n PERIOD AMPLIFIER
GENE@& DESCRIFTION
l-3.
SP.ECIFICAlTONS.
OC.
RANGR
ZFAO DRIFT:
RISE TIME:
imum setting):
ACCURACY:
LIKEA.R-LCS RELAlTONSHIp: Within 2s of
within
Single scale, from lo-l2 to 10m4
Less than
l/6
decade in 24 hours after a one-hour warmup.
Seconds to 9C$ of final current value (DAMPING control at min-
Current Change
Amperes
10-12
to 1o-ll
10-n to 10-5
With No Significant
External Capacitance Across Input
3 seconds
1 second
Within 0.2 decade.
5s
of full scale from lo-5 to lo- ampere.
MODEL 421 MG n PERIOD AMPLIFIER
empere; positive currents only.
With 5000 pf
6 seconds
2 seconds
11 scale from lo-l2
to 10-5 ampeve
4:
ouTpuTs:
1) Zero at lo-l2
empere, increasing as 8 negative voltage 10
volts per decade to -80 volts at 10" ampere: up to one mil-
liampere may be drawn.
2) Recorder output of 50 millivolts full scale is supplied for
servo rebalance recorders.
RAITGE: Single scale, from -30 to infinity to
3%
at
-6
ACCURACY:
RESPONSE SPEED:
FiEEOVETfY TIME:
OuTcPum:
1) Minus one volt for -30 second period; zero for Infinite per-
seconds.
3 seconds maximum to 9% of final value.
10 seconds maximum.
iod; +lO volts for 3-second period.
2) Recorder output of 50 millivolts full scale is supplied for
servo rebeLlance recorders.
+3 seconds.
FOLARIzING FOTSNTIAL:
TABLE 1 (Sheet 1). Model 421 Specifications
l-2
+225 volts for ion chambers.
0563
MODEL 421 LOG n PERIOD AMPLIFIER
CONNEC~RS: Input: Type HN (UG-560/U) receptacle.
+225 volts:
All Outputs:
TUBE CO- One EA52, one OA2, one CG3, one 12AU7, two 12AX7, one
12~~7, ITOIW 5886, one 6~~6, one 6~~4, two 6x16, one 6~4, one ~Y&JA.
TR4NSISMR COMPLEMENT:
Amphenol 80-C receptacle.
Microphone receptacles.
One 2~1183, four 2~1381, one 2N1535.
GEXERAL DESCRIPTION
POWER:
ACCESSORIES SUPPLIED:.
ACCFSSOFUES AVAILABLE:
tubes in a plug-in can (replacement spare).
DIMENSIONS:
mxr WEIGIIT: 23 pounds.
1-J+. FxqJnMENT SHIPPED. The Model 421 Log q Period Amplifier is factorycalibrated and is shipped with all components in place.
also contains the Instruction Manual and a set of six mating input and out-
put plugs.
l-5. REGISTRATION CARD.
of the Instruction Manual. Please fill it out and mail it when you receive
the instrument.
1-6.
follow the instructions given at the back of the ma~lual for reporting the
defect.
105-125 volts or alO-250 volts, 50-60 CPS, 50 watts,
set of six mating plugs.
Model 4102 Input Assembly, two 5886 electrometer
B-314 inches high x 19 inches wide x 12 inches deep.
TABLE 1 (Sheet 2).
The registration card is attached to the front cover
DAMAGE IN SHTPMENT. If *he Model 421 is damaged or faulty when received,
yodel 421 Specifications.
The shipping carton
0563
l-3
MODEL 421 MG n PERIOD AMPLIFIER
SECTION 2. OPERATION
2-1. FRONT PANEL CONTROIS.
OPEXKCTON
a. ON-OFF.
the instrument on. The pilot light is directly above the switch.
OPERATE - SE72 10-5 - SET lo-=.
b.
the log n amplifier to function as a logarithmic micro-microsmmeter. The
switch also allows the amplifier to be oalibrated at two points, 10-5 and
1oJl
log n amplifier to lo-11 ampere when the PPERATE switch is in SET lo-11
position.
log n amplifier to 10
quick dissipation of spurious charges which sometimes accumulate on the input terminal. It also allows the amplifier to recover quickly from large
overloads.
balance to read lo-12 ampere on the meter when the RECOVER switch is depressed.
circuit is normal with the period input connected to the log n amplifier
output.
log n amplifier to the period circuit. When the switch is at CHECK 00, the
period meter should readoo .
ampere.
C. SET 10-l-l.
d. SET 10-5.
e. RECOVER.
f. AMPLIFIRR RALANCE SET 10-12. This potentiometer adjusts the amplifier
OPERATE-CHiXKw.
g.
In the CHECK W position, the switch removes the signal from the
The ON-OFF control is a double-throw toggle switch which turns
In OPERATE position, the switch allows
The SET lo-11 potentiometer on the front panel adjusts the
The StT 10'5 potentiometer on the front panel adjusts the
-5
ampere when the OPERATE! switch is in SST 10-5 position.
The RECOVER switch shorts out the feedback diode and allows
With this switch in OPERATI? position, the period
h. SEToo.
OPERATE-CHECK 00 switch is at CHECKoo .
2-2.
(Amphenol 82-805).
chambers through an Amphenol %C receptacle.
amplifier meter deflection, and one milliampere can be drawn without upset-
ting the circuits, through a microphone-type receptacle (Amphenol 80 PC2F).
ect connection to servo rebalance recorders.
approximately 50 ohms.
0563
REAR CHASSIS CONTROLS ANDTERMINALS.
a. INPUT. The INPUT is a RN series receptacle, Military type US-560/U
b. +225.
C. &I V IOG N OUTPUT. Minus 80 volts are developed for full-scale log n
d. 50MVMGNOUTHJT.
This potentiometer adjusts the period meter to 00 when the
A polarizing potential of ~225 volts can be supplied to ion
Fifty millivolts are provided for convenient, dir-
The internal resistance is
2-l
Ol?ERATION
MODEL 421 MG n PERIOD AMPLIFIER
e. 10VPERIODOUTKIT.
for a +3 second period.
f. 50 MV PERIOD OUTHJT.
direct connection to servo rebalance recorders. The internal resistance is
approximately 50 ohms.
g. DAmmG.
lifier.
wise.
2-3. INHJT COI'TIWTION.
a. The current source should be connected to the INHIT with the high impedance side of the current source associated with the central conductor of
the RN type receptacle.
since spurious input signals will occur caused by capacitance changes and
generation of static charges.
b. The lead-in cable should be Polyethylene-, Polystyrene- or Teflon-
insulated coaxial cable; the plug should have Teflon insulation. For large
cables, Amphenol 82-804 plugs are recorunended; for small cables, Amphenol
82-816 plugs are recoxmnended. During the preparation of the cable and plugs,
it is essential that all high impedance surfaces be kept scrupulously clean
to avoid leakage. With graphite coated cables, it is necessary to avoid
tracking graphite onto the high impedance surfaces of the cut end of the
insulation and onto the Teflon surface of the plug.
Maximum damping is obtained by rotating the control fully clock-
The control varies the response time over a ten-to-one ratio.
The damping control slows the response of the log n amp-
Ten volts are developed by the period circuit
One milliampere can be drawn.
Fifty millivolts are provided for convenient,
Avoid movements of the cable during measurements,
,
2-4. OWm moc!EmTREs.
a. Turn on the power switch, After a &minute warmup, check the amplifier balance by depressing the RECOVER switch. The log n meter should
read lo-l2 ampere; if necessary, adjust the meter-pith the AIQLIFIER BALANCE
contra
to lo-
ATS switch to 10-Y position.
with the SET 10-5 control.
b. Check the period circuit by putting the OPERATE-CRFCK DC) switch in
CHECK 00 position. If the period meter does not read-, adjust the SETW
control for the correct reading.
c. Occasionally recheck the calibration of the log n amplifier andthe
period circuit. Adjust if necessary.
ments should be necessary.
2-5. DAMPING.
a. The speed of response, or the time constant of the ion chamber and the
log n amplifier, depends upon the speed of response of the circuitry of the
instrument and also upon the capacitance of the current source and its connecting cable. Because of the method of negative feedback applied to the
log n amplifier, the significance of the external input capacitance is de-
Turn the log n and set the log n meter
il
with the SET 10'
erz"""' to SET 10
Check calibration by turning the OPER-
If necessary, adjust the meter to 10-5 ampere
After warmup, only infrequent adjust-
2-2
0563
MODEL 421 LOG n PERIOD AMXIF!ER
creased; quite large capacitances can be tolerated without greatly increasing response times. Therefore, a cable run from an ion chamber to the instrument is permissible.
b. Variable damping of the log n amplifier is provided by the potentio-
meter on the back of the chassis adjacent to the input receptacle. Maximum
damping is obtained by rotating the control fully clockwise. The damping
slows the response of the log n amplifier so that it tends to average the
statistical noise of the ion chamber current and the noise generated in the
input cable. Therefore, when the log n amplifier output is differentiated
in the period circuit, false short periods will not be indicated.
2-6. REWORDING.
OPFIRATION
a. The log n amplifier and the period circuit both have two outputs:
for 50-millivolt recorders, and the other for auxiliary panel meters or
controls.
b. Fifty-millivolt recorders are plugged directly into the 50-millivolt
output receptacles.
The internal impedance is approximately 50 ohms. Resistor dividers for more
sensitive recorders can easily be made at the recorder input.
C. Alarm and remote indicating circuits can easily be connected to the
high-level outputs. Amplifiers and cathode ray oscilloscopes are also connected to the high-level outputs.
ground potential.
2-7.
to provide t225 volts for polarizing an ion chamber. The potential is derived directly from the electronically regulated power supply. The chassis
connector is Amphenol 80 C;
+225 VOLTS.
Roth 50-millivolt receptacles are Amphenol 80 FCZF.
Terminal No. 1 of each connector is at
A receptacle has been mounted on the back of the chassis
the mating plug is Amphenol 80 M.
one
0563 2-3
MODEL 421 w n PERIOD AMPLIFIER
SECTION 3. CIRCUIT DESCRIPTION
CIRCUIT DESCRIPTION
3-1. GEFNERAL.
amplifier, the period circuit and the power supply.
The circuit designations used In this section refer to the
schematic diagram, 16298D, found at the back of the Manual.
The Model 421 contains three principal circuits, the log n
NOTE
Ixx; n AMPLIFIER
PERIOD CIRCUIT
FIGUF3 2. Simplified Circuit Diagram of Model 421.
3-2. LOG N AMPLIFIER CIRCUIT,
a, The log n aqlifier is principally a micro-micmatuneter whose logarlthmic scale is obtained by negative feedback from output to input through a
diode operated in the velocity field region. The diode used is an ~52 spec-
ial purpose tube.
b. The PA52 offers outstanding advantages in this application:
1. The insulation of the EA52 is of a very high order. Therefore, the
diode plate has very little leakage which would cause erratic effects in
the low current region.
Since this tube is an uhf diode, the capacity across it is minimal.
2.
This results in a considerable improvement in response speed over instru-
ments which employ conventional diodes.
0563
3-l
CIFXXIT DESCRIPTION
MODEL 421 IOG n PERIOD AMPLIFIER
c. The feedback from the output is connected through potentiometer R106 so
that adjusting ~106 will control the potential in series with the output.
This potential is necessary to buck out the voltage across the diode in order
that the log n amplifier output can be kept at ground potential when the in-
put is at ground potential.
The amplifier of the log n circuit consists of two 5886 electrometer
d.
tubes, V2 and V3, followed by high gain pentodes, V4 and V5. Feedback from
the cathodes of V4 and V5 to the screens of V2 and V3 stabilizes the plate
potentials of V2 and V3.
Additional gain is provided by V6a. VT is a con-
stant-current coupling element between v6a and V6b, which is the cathode fol-
lower output for the log n amplifier.
The constant-current coupling element
eliminates attenuation so that the output will develop -80 volts for fullscale deflection. The output drives the diode feedback circuit, the panel
meter, the high-level and the 50-millivolt outputs plus the period circuit.
The circuit outpu potential is zero for lo-l2 ampere meter indication, and
-80
volts
for 10'
through a resistive voltage divider.
$
ampere indication.
The 50-millivolt output is supplied
The open loop gain of the amplifier is
approximately 10,000; the feedback factor is approximately 1000.
e. The calibration circuit consists of a 1.34-volt mercury battery, Bl,
and resistors RlOl, R102, R103 and R104.
The log n OPERATE switch Sl is used
to select the desired signal, either 1C-11 or lo-5 ampere.
The meter calibration is established by alternating between the 10-l-l
f.
and the 10m5 positions of the OBEFNE switch, which causes lo-11
ampere to flow in the input.
The potentiometers Rlll and R106 are adjust d
until these calibration signals read properly on the meter.
or 10-5
The SET 10-l?
control, Rlll, adjusts the feedback voltage in series with Vl and thus sets
the static resistance of the diode at one point. The SET 10-5 control, R106,
adjusts the gain of the amplifier and thus ad.justs the change of the diode
voltage with current, so that the remainder of thbscale reads correctly.
Once these adjustments are made, only the SET 10'
control needs to be used
to compensate for diode drift. The other controls will require infrequent
adjustment.
With the RECOVER switch depressed, the log diode, Vl, is shorted out.
g.
In this condition the logarithmic characteristic of the amplifier is removed
and the ci cuit is simply a linear feedback amplifier whose zero corresponds
to the lo-
adjusts the amplifier zero.
iEz
position on the meter. The AMPLIFIER BALANCE potentiometer R116
With proper balance of the amplifier, dc voltage
at the input will be less than five millivolts in normal operation.
h. Cl01 is the damping capacitor which slows the response of the log n
amplifier.
sponse is damped the least.
With the low impedance end of Cl01 connected to ground, the re-
As more and more feedback
signal from
the output
is introduced at the low impedance end of ClOl, the damping is increased.
The damping control, RlOg, increases the feedback voltage until the desired
amount of damping is obtained.
3-3.
PERIOD CIRCUIT.
a, The period circuit is an operational amplifier connected as a different-
3-2
0563
MODEL 421 LOG n PERIOD AMPLIFIER CIRCUIT DESCRIPTION
iator.
C201 is the differentiating capacitor and RZOl is placed in series
with the capacitor to lessen response to very high frequencies. The feedback resistor R2l.l determines the sensitivity of the period smplifier. RZll
is returned to potentiometer R2Zl so that the feedback factor can be varied.
In this way, the calibration of the period circuit may be adjusted. Capacitor C204 slows the circuit response to about one second full scale.
b. The period amplifier consists of balanced 5886 tubes followed by a
12ALl7 tube connected as a differential amplifier. Feedback from the 12AU7
cathodes to the
the 5886 tube plates.
screens
of the 5886 tubes stabilizes the operating point of
Vll, a cathode follower, drives the output meter and
the feedback loop. The open loop gain of the amplifier is approximately 200.
The circuit output is 10 volts for a positive period of three seconds.
c. The CHECK 00 switch S3 in the CHECK position grounds one terminal of
C201 and leaves only the grid of ~8 connected to the feedback resistor.
This condition corresponds to infinite period or no change in output from
the log n amplifier. If the period meter does not point to infinity in this
position, it may be adjusted by ~206.
d. D201 and D202 are zener diodes connected back-to-back to limit the
amplifier input voltage in case of overload. Substantial decrease in recov-
ery tti is provided by these diodes.
3-4. POWER SUPPLY.
a. The Model 421uses an electronically regulated +Z25 volt supply, a VR
tube regulated -150 volt supply, and a transistorized -12 volt supply.
b. The +225 volt supply utilizes a type 6~6 series tube, Vl3, which is
controlled by a two-stage differential dc amplifier, Vl4 and V17. V17 compares the B plus voltage, sampled via R3l2 and R314, to the voltage of reference tube ~16. The output of Vl7 is amplified by Vl4 and used to control
the resistance of the series tube V13.
pears on the back of the
chassis
is taken directly from the +2Z5 volt supply.
c. The -150 volt supply is derived
conventional RC filter network.
The minus supply is derived from a half-
The polarizing potential which ap-
from
full-wave rectifier V12 and a
wave rectifier, D301 through D304, and filtered with a three-stage RC filter,
R304 and C3O2, R305 and C303, ~306 and C304, and finally regulated at -150
volts by V15.
d. The log diode filament voltage power supply consists of an ultra-stable
transistor regulator which supplies 12 volts at 1.2 amperes. The regulation
of this power supply is better than 0.005% for a line voltage variation of
100 to 130 volts.
0563
3-3
MODEL 421 LOG n PERIOD AMPLIFIi!X
MAINTENANCE
SECTION 4.
4-l. GERERAL.
a. The Keithley Model 421 Log n Period Amplifier has been designed to give
long, trouble-free service.
out, and the circuits are stabilized by a substantial amount of negative
feedback.
b. The detailed circuit schematic diagram 16298~ is at the back of the
manual.
3, Circuit Description, contains an explanation of the function of the prin-
cipal circuit components.
4-2. ELEC'PROMETEX IUBES.
a. Two pairs of electrometer tubes,
in an aluminum can which plugs onto the top of the chassis. Each can is
labeled Model 4102 Input Tube Assembly. These tubes have been selected,
matched and labeled; the Keithley part number is EV5886-5. It is recommended
that the complete input tube assembly be kept on hand for replacement purposes.
b.
This
to lo- E ampere. This tube must be selected to operate over this range; order
replacements only through Keithley Instruments.
Circuit designations in this section refer to this diagram. Section
A type EA52 electrometer tube, Vl, is used &s the log diode elementi
t be is tested for logarithmic characteristics over the range of 10
High quality components have been used through-
MAINTENANCE
V2 and V3, ~8 and Vg, are each located
4-3. INSULATION.
of Teflon, &s are the contact insulators on the log n OPERATE switch. This
should give satisfactory service in all humidities. Occasionally, the high
impedance insulators should be inspected to insure that they are free from
dirt and dust, and they should be brushed off if necessary.
4-b.. CONNECTOR CAP,
whenever the input is not being used. In storage and in transport, it keeps
the insulation from accumulating dust, dirt and moisture. Before screwing
the cap back onto the receptacle, be certain that it is clean, so the insula-
t-ion will not be contaminated and so a low impedance bridging conductor will
not be formed between the high impedance contact and the grounded cap.
4-5. REFERENCE VOLTAGE BAITER?!.
yearly.
easily seen when the bottom plate is removed. Replace with either a Mallory
RM-k0l.R or a Burgess Hg-I+OlR battery.
4-6. CALIBRATION OF MG n AMPLIFIER.
a. Connect a volkmeter (recommended instrument is the Keithley Model 610A
Electrometer) to the 80 V MG N OUTPUT receptacle. Observe proper polarity.
Depress the PECOVER switch on the front panel and adJust the AMPLIFIER BALANCE control until the voltage at the output is 0 volts (+O, -10 millivolts).
It is mounted on the PC board near the input receptacle; it is
All insulation for the high impedance conductors is made
The cap for the input receptacle should be kept in place
Battery Bl should be replaced at least
0563
4-1
MAINTENARCE
MODEL 421 LOG n PERIOD AMPLIFIER
There must be no positive output or the instrwnent will not calibrate properly.
b. Apply a lO-4
on the log n meter.
Model 421 zimmediately behind the log n meter) for
c, Adjust the SET 10-5 and the SET lo-11
2-4,
a.
4-7.
CALIBRATION OF PERIOD CIRCUIT.
ampere current to the INPUT to obtain a full-scale deflection
Adjust the IOG CAL potentiometer R135 (located inside the
-80
volt output.
controls as described in paragraph
If period calibration is to be checked,
a test setup as described below is recommended.
a. To simulate the exponential change in reactor power level, a capacitor
discharge may be used to set up an electrical analog.
The voltage discharge
mey be converted into a current by using a Himeg resistor to connect the cap-
acitor into the log n amplifier input as shown in Figure 3,
FIGURE 3.
Diagrem for Calib-
ration of Period Circuit
The period circuit, if correctly calibrated, should read directly the
b.
time constant of the RC network (Rl and C) as C is allowed to discharge through
Rl when the key is opened With a loo-volt source end the key closed, the Log
n Amplifier will read lo- 8 ampere.
When the key is opened, after an initial
transient, the period circuit should read RlC, In practice, C should be 1 to
10 microfarads and Rl varied to give various period readings. A time constant
or period of six seconds is a convenient calibration point. With the values
shown, the pe iod indicatio
*bout 5 x 10
-5
to about lo-
will be accurate from a current reading of
20
ampere and any period calibration should be
made while the current is in this range. Adjust the period meter with the
CffiIHRATE PERIOD potentiometer R221, located inside the Model 421 immediately
behdnd the period meter.
c. Note that since the instrument can only be calibrated on negative period
with this arrangement, the meter leads of the period meter should be reversed
for this calibration.
4-z
0563
MCDRL 4211& n PRRIODAMPLIFIW
RRPLACEABLEPARTS
SECTION 5.
5-1.
Log n Period Amplifier.
scription, a suggested manufacturer and the Keithley Pert Number.
and address of the manufacturers listed in the "Mfg. Code" col!mm is contained
in Table
you receive. These substitutions do not impair the performance of the instrument . Either the substitute part or the part specified in the Replaceable
Parts List may be used for replacement purposes.
5-2.
Keithley Part Number, the circuit designation and a description of the part.
All structural parts end those parts coded for Keithley manufacture
must be ordered from Keithley Instruments, Inc. In ordering a part not listed
in the Replaceable Parts List, completely describe the part, its function and
its location.
lG3FLAcm PARTS LIST.
a. The Replaceable Parts List describes the components of the Model 421
The List gives the circuit designation, the part de-
3.
b. In some instances, it is necessary to substitute parts in the instrument
Ig)wTooRDERPARTS.
a. For parts orders, include the instrument's model and serial numbers, the
REPLACEABLE PARTS
The name
(80164)
If any part ordered has been replaced by a new or improved part, the new
b.
part will be shipped.
c. Order parts through:
Sales Service Department
Keithley Instruments, Inc.
1.2415 Euclid Avenue
Cleveland
Telephone
amp
CbVar Carbon Variable
CerD
camp
DCb
m
f
I
k
M or meg mega (106) or megohms
ampere
Ceramic, Disc
Composition
Deposited Carbon
Electrolytic, metal cased
kilo (103)
milli (10-3)
k
Manufacturer
TABLE2
Abbreviations and Symbols.
0563
6,
Ohio
795-2666,
Ml1 No.
k
i-i
pa?
P
Tar
zw
WWVar
Area code
Military
micro (10' )
Mylar
OhU
PolystyreB
pica (10'
volt
Variable
watt
Wirewound
Wirewound Variable
216
Y?
e Number
)
5-l
REPLACEAELEPARTS MD?% 421r.a nPERIODAM%IQW
MODEL 421 REPLACEAPAE PARIS LIs!r
(Refer to Schematic Diagram 16298D for circuit designations)
CAPACI!lmE!
Circuit
Desig.
Cl01
cl.02
Cl03
Cl04
cJ.05
~106
c201
c202
c203
C204
c301
c302
c303
c304
c305
~306
c307
~308
Value
150 pf
*.0001 pf
50 vf
0.02 jlf
.OcOl~
0.001 &f
1.0 pf
*.wo1 &e
50 Pf
0.1 fl
16
fl
3.6
wf
20
crp
20 wf
0.02 )Lf
0.02 jlf
0.1 &
20
vf
Rating
500
”
me
p0J.Y
CerD
2: v
69OV
C-00 v
6ooV
IBE
CerD
CarD
CerD
w
gf ::
400 v
CerD
T
600-J E&c
V
EM!
g v
450 v z
600 v
CerD
63OV CerD
MY
g::
Eta
Mfg.
Code
KeitbJ.ey
Part No.
71590 C138-150P
oll21 c22-l.OQP
83125
72982
c17-5OM
C22-.02M
OIL21 c22-loop
i’2982
c22-.oolM
00686 C37-LOM
Oll.21
83125
c22-loop
C17-50M
00656 c30-o.lM
14655
14655
c34-16&l
C34-16M
C7-2OM
;;E
72982
72982
C'7-20M
c22-.02M
c22-.02M
00656 c30-o.ul
37942
~7-20~
C401
c402
c403
c404
500 crf
500 bf
0.01 &f
500 I@
50 v
50 v
600 v
25 v
DIODES
circuit
Desig.
rype
D201 Zener
D202
D301
~302
D303
Zener
Selenium
Selenium
Selenim
D304. Selenium
D305
Silicon
~306 Silicon
Number
lN706
lN706
pro65
pro65
pro65
pro65
J-N3253
m3253
*Component in Model 4102 Input Assembb
Eta
Eta2
CerD
EM:
14655
14655
c57-500
c57-500
oll21 c22-.olM
l4655
m3.
~58-500
Keithley
Code Part No.
12954 DZ-1
12954 DZ-1
81.483 ~~-18
81483 ~~-18
81483 ~~-18
am33 ~~-18
02735
02735
RF-20
RF-20
5-2
mDEL 421 ICC n PERIOD AMPLIFIER REPLACEmLEPARTS
DIODES (Cont'd)
circuit
Desig.
Dtil
2lz;
Circuit
Desig.
Bl
52
---
33
54
55
~6
Keithley
DZ-1
RF-14
Type
Zener
Silicon
Zener
Mfg.
Number
Code Part No.
lN706 12954
Wla2
IN715
12065
12954 DZ-22
MISCELLANEOUS PARTS
Keithley
J?u-2
m-8
Description
Battery, 1.34 v Mercury (Mfg. No. RM4W-R)
Fuse, 3 amp, 3Ac
Fuse, 1.5 amp, 3 AG
Fuse.holder -. -
Mfg.
Code Part No.
37942 m-8
75915
75915
75915 m-3
Receptacle, RR Series, INPUT, Mil No. UC-560/U 02660 cs-30
(Mpg. NO. 82-805)
(Mating plug is Keithley part CS-31)
Receptacle, Microphone, +225
Plug, Microphone, Mate of J'2
Receptacle, Microphone, 50 MV LCG N OUTPJT
Mfg. No. a C)
Mfg. No. 80 M)
t
02660 cs-34
02660 cs-35
02660 cs-32
(Mfg. No. 80 FCZF)
(Mating plug is Keithley part CS-33)
Receptacle, Microphone, 75 V LCG N OUTPUT
02660 cs-32
(Mfg. No. 80 PC2F)
(Mating plug is Keithley part CS-33)
Receptacle, Microphone, 50 MV PERIOD OUTPUT
02660 cs-32
(Mfg. No. 80 FC2F)
(Mating plug is Keithley part CS-33)
Receptacle, Microphone, 10 V PERIOD OUTPUT
02660 cs-32
(Mfg. No. 80.PC2F)
(Mating plug is Keithley part CS-33)
Ml Meter, Log n
M2 Meter, Period
--..--
Pl
P2
---
P3 to P6
Sl
--m-e
s2
Pilot Light Assembly
Bulb, Miniature bayonet base, (Mfg. No. 51)
plug, RR Series (Mfg. NO. 82-816)
Line Cord
Cable Clamp
Plug, Microphone (Mfg. No. 80 MC2M)
Rotary Switch less components, OPERA!PE
Switch Assembly with components, Operate
Skirted Knob Assembly, Operate Switch
Push Button Switch Assembly, RECOVER
1066R
80164 m-28
80164 m-4
80164 m-g
08804 a-8
02660 cs-31
80164 co-2
80164 cc-7
02660 cs-33
80164 SW-38
8a64 163018
80164 15459A
80164 14130B
5-3
MISCELLANEOUS PARTS (Cont'd)
circuit
D&ii@:.
Et
Tl
c 1rcuit
Desig.
RlOl
R102
R103
R104
R105
R106
Xl07
R108
RlO9
RLLO
Description
Toggle Switch, SPIY.C, OPERATE - CHf%K 00 04009
Tog&e Switch, SPST, ON-OFF 04009
Transformer
RFsISloRS
m3.
Value Rating
34
MJ
??lm
lo n
75 kR
27.3
161
2OOs-l
500
n
300
kQ
3m
10 Its-l
Type
wwvar
DCb
DCb
WWVar
corn
Code
E22:
63060
01661
01661
71450
00327
00327
71450
OU.21
Mfg.
Code
80164. TR-60
Keithley
Part No.
Rl2-34K
gt:EP
RI&75K
~12-27.3~
~~3-200
Rl2-500
RI%3OOK
m3-3K
Rl-1OK
Keithley
Part No.
SW-5
SW-4
RSIJ.
Rl32
R=3
RLl.4
Ru5
RlJ6
R-U.7
RlJ.8
RlLg
Rl20
RI.21
Rl22
~123
RI.24
RI.25
R126
X127
RL28
Rl29
R130
Woqponent in Model 4102 Input Assembly
50
u-l
50
xl
*22 m
*10 m
*lo m
200 i-4
150
D
250 s-l
22.5
6~2
22.5
220 la
470
1.14
l.oMl
m
b-2
-x-z
MCI
wwvex
Xb
Camp
Deb
DClb
WWVar
ww special
WW Specidl
ww
IXb
ww
IYzb
Deb
.Txb
DCb
camp
DCb
Lx3
Eb
camp
73138
00327
44655
00327
00327
02lLL
zk%
63743
01661
OU.21
00327
00327
01661
M55
RP4-50K
RX?.-5UK
Rl-22M
RlZ-10M
RlZ-lOM
~~23-200
R65-150
R65-250
~5-22.5K
Rl.3-6M
~5-22.5s~
Rl2-220K
~12"47OK
RI&l.lti
RX?-10K
Rl-LOK
R12-600K
RI&6QK
RI&l&
R2-XCOK
5-4
1066R
WDFZ 421LoG n PERIODAMPLIFIEB
REPLACEABLEPARIS
RESISMRS
Circuit
De&g. Value Rating
R131
~I.32
R133
R134
Rl35
~136
ru37
~138
R201
R202
~203
~204
~205
~206
~207
~208
R209
R210
1.5 MQ
22.5 ks-2
50 kQ
250 ks2
500 kQ.
50 fi
4mm
75 m
600 la
47 M?
*22 ml
*lo I"m
*lo MQ
200 a
150 a
250 n
22.5 x-2
~MQ
(Cont’d)
Keithley
RITZ-1.5M
~5-22.5~
Ejl2-50K
RX&250K
RP7-500K
RITZ-50
RIdlOOK
Ru-75K
Rl2-600K
Rl-47K
RL-22M
R12-lOM
R12-10M
~~3-200
Type
IX!b
ww
IYJb
SCb
CbVar
Eb
Deb
Eb
Eb
cow
camp
Eb
Eb
war
WT.
code Part No.
01661
63743
k%:
71450
01661
32:
00327
E;ii
00327
00327
71450
WW Special 80164 R65-150
WW Special @x64 x65-250
ww
63743
EC 01661
~5-22.5~
R13-6M
R2ll.
X212
~213
~214
R215
~216
R217
~218
R219
R220
X221
R222
~223
R224
X225
R301
~302
R303
R304
R305
5.25 MQ
22.5 m
l.oola
100 162
1m
3.4 M-l
allal
1.5 im
22.5 Idl
1162
3 161
6Kl
gl?
55 PJ?
loon
loos-l
3*3 MQ
1250 s-2
1250 s2
Eb
ml
Eb 01661 Rl2-MOK
Eb 01661 Rl&lOOK
DCb
DCb
Eb
rxb
wd
Wb
WWVar 71450
Eb 01661
LXb 01661 R12-LOK
Xb 01661
Eb
ww
cow?
cow 44655
ww
ww
Womonent in Model 4102 Inuut Assemblv
00327
63743
00327
00327
32
63743
00327
01661
44655
Oll21
44655
63743
~13-5.25~
~5-22.5~ _
Rl2-lM
R12-3.4K
RlZ-@K
RL2-1.5M
R5-22.5K
X12-lK
RP3-3K
Rl2-6K
~12-50
Ra-55K
X4-100
Rl-100
Rl-3.3M
R5-I.250
R4-I.250
1066R
5-5
REsIS~FfS (Cont ' d)
circuit
Dssig. Value
x306
I.250 s1
5m
~~~
R309
R3J.o
R3=
~312
28%
2.2 xl
2.2 m
1Msl
R313
R314
R4Ol
R402
R403
R404
R405
R406
R407
R408
lam
lokn
150 kSl
6&a
lokn
4.7 kn
*500n
i%:
R4Xl
++qoo n
47 s-l
Rating
NJ%, 5 w
ww
Mpg.
code
00327
00327
00327
01661
00327
yG;:
Oll.21
OU.21
OlJ.21
44655
OlJ.21
oll21
0327
a327
91637
Keitliley
Part No.
R4-1250
R4-5K
Rl-lM
~2-68~
R.l.2"2.2M
RI&2.2M
lCL2"lM
RJ.2"1.3M
Rl2"&OK
R6"5
Rl-560
Rl-lOK
RI.-loK
RL15OK
Rl-680
Rl-.l.OK
Rl-4.7K
Rl2-500
~12-500
R4A-47
TRAWISTXS
circuit
Desig.
Number
Mfg.
code
mm3 02735
:;
2~1381 01295
3 2~1381. 01295
2~1381
ol.295
45 2~1.381 01295
46
Circuit
Desig .
Vl
v2
2
v5 %2
Component in Model 4102 Input Assembly.
WNominal value, factory selected.
2Nl-535
VACWM~
Nuder
ME2
~5886
'~5886
802ll
WT.
Code
E%i
em64
94154
94154
Keithley
l%xt NO.
XKil
s::
iis
m-7
Keitbley
Part No.
5-6
1066R
MODEL 421Ice n
PERIOD AMPLIFIER RFPLAcEABLEPAFiT;
VACUUM !WEE3 (Cont ' d)
circuit
Desilx.
v6
v7
v8
v9
VlO
VI-J-
VIZ
v13
v14
VI.5
~16
VI7
Number
iz?
*5806
*5886
m7
z4
6y6Gn
7025
OA2
w3
7025
Mfg.
Code
86684
8535%
Keithley
Part No.
EV-l2.m
EV-6~6
Epg;;
&U3+
73445
" "
Ev"l2Au7
86684 EIv"6c4
0COl.l
OQOll
73445
85599
PI-61~4
Eiv-6YcGA
N-7025
EV-OA2
Ev"cG3
EV-7025
Component ti I&de1 4102 Input Assembly
1066K
5-7
REPLACEABLE PARTS
MODEL 421 LOG n PERIOD AMPLIFIER
0011 Sylvania Electric Products, Inc.
Electronic Tubes Div.
Buffalo, N. Y.
0327 Welwyn International, Inc.
Cleveland, Ohio
0656 Aerovox Corp.
New Bedford, Mass.
0686 Film Capacitors, Inc.
New York, N. Y.
1121 Allen-Bradley Corp.
Milwaukee, Wis.
1295 Texas Instruments, Inc.
Semi-Conductor Products Div.
Dallas, Texas
1661 Wilrite Products, Inc.
Cleveland, Ohio
2111 Spectral Electronics Corp.
San Gabriel, Calif.
2660 Amphenol Connector Division
Amphenol-Borg Electronics Corp.
Chicago,
2735 Radio Corp. of America
RCA Semiconductor & Materials Div.
Somerville, N. J.
Illinois
44655 Ohmite Mfg. Co.
Skokie, 111.
56289 Sprague Electric Co.
North Adams, Mass.
63060 Victoreen Instrument Co.
Cleveland, Ohio
63743 Ward Leonard Electric Co.
Mount Vernon, N. Y.
71450 CTS Corp.
Elkhart, Ind.
72982 Erie Resistor Corp.
Erie, Pa.
73138 Helipot Division
Beckman Instruments, Inc.
Fullerton, Calif.
73445 Amperex Electronic Corp.
Hicksville, N. Y.
75915 Littelfuse, Inc.
Des Plaines, 111.
80164 Keithley Instruments, Inc.
Cleveland, Ohio
80211 Motorola, Inc.
Chicago, Illinois
4009 Arrow-Hart & Hageman Electric Co.
Hartford, Corm.
8804 General Electric Co.
Lamp Division
Cleveland, Ohio
2065 Transitron Electronic Corp.
Wakefield, Mass.
2954 Dickson Electronics Corp.
Scottsdale, Ariz.
4655 Cornell-Dubilier Electronics
Div. Federal Pacific Electric Co.
Newark, N. J.
,7942 Mallory, P. R., and Co., Inc.
Indianapolis, Ind.
TABLE 3.
5-8
Code List of Suggested Manufacturers.
81483 International Rectifier Corp.
El Segundo, Calif.
83125 General Instrument Corp.
Capacitor Division
Newark, N. J.
85599 General Electric Co.
Schenectady, New York
86684 Radio Corp. of America
RCA Electron Tube Div.
Harrison, N. J.
91637 Dale Electronics, Inc.
Columbus, Nebr.
99942 Hoffman Electronics Corp.
Semiconductor Division
El Monte, Calif.
1066R
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