Elenco Electronics XK-550K Assembly And Instruction Manual

DIGITAL / ANALOG TRAINER

MODEL XK-550K

A COMPLETE MINI-LAB FOR BUILDING,TESTING

AND PROTOTYPING ANALOG AND DIGITAL CIRCUITS

Elenco Electronics, Inc.

Copyright © 1995 Elenco Electronics, Inc. Revised 1999 REV-F 753550K

Tools and meter shown not included.

Assembly & Instruction Manual

-1-

PS-550-B

XK-550K POWER SUPPLY KIT (PS-550-B) PARTS LIST

RESISTORS

QTY SYMBOL VALUE DESCRIPTION PART #

r 2 R1, R2 120Ω 5% 1/4W (brown-red-brown-gold) 131200
r 1 VR3 1KΩ Pot PC MNT 192412
r 2 VR1, VR2 2KΩ Pot PC MNT 192421
r 1 VR4 100KΩ Pot PC MNT 192612

CAPACITORS

QTY SYMBOL VALUE DESCRIPTION PART #

r 5 C6 - C10 .1µF 100V Mylar 251017
r 7 C11 - C17 100µF Electrolytic 281045
r 4 C1, C2, C4, C5 1000µF 35V Electrolytic 291096
r 1 C3 2200µF 25V Electrolytic 292225

SEMICONDUCTORS

QTY SYMBOL DESCRIPTION PART #

r 15 D1 - D15 1N4001 Diode 314001
r 1 U1 LM317 Integrated Circuit 330317
r 1 U5 LM337 Integrated Circuit 330337
r 1 U3 LM7805 Integrated Circuit 337805
r 1 U2 LM7812 Integrated Circuit 337812
r 1 U4 LM7912 Integrated Circuit 337912

MISCELLANEOUS

QTY DESCRIPTION PART #

r 1 Transformer 44K500
r 1 PC Board 514550
r 1 Fuse 1.25A 530125
r 1 Switch Illuminated 541204
r 2 Connector 3-pin 591032
r 1 Connector 5-pin 591052
r 1 Bracket 613003
r 4 Bracket L 4-40 tap 613008
r 1 Panel Top 614102
r 1 Panel Side Right 614551
r 1 Panel Side Left 614554
r 4 Knob 622009
r 1 Case 623002
r 1 Bushing 624009
r 1 Spacer Nylon 7/16” x 3/16” Tap 624013
r 1 Connector Receptacle 626020
r 1 Connector Plug 626021
r 1 Cord Retainer 628003
r 9 Screw 4-40 x 1/4” Slotted 641430
r 1 Screw 4-40 x 1/4” Phillips 641431
r 8 Screw 6-32 x 5/16” Slotted 641641
r 2 Screw 8-32 x 3/8” Phillips 641840
r 2 Screw #4 x 1/4” Phillips AB 642430
r 4 Screw #8 x 1/2” Phillips AB 642862
r 4 Screw #6 x 3/8” Phillips Thrd Ct 643652

QTY DESCRIPTION PART #

r 4 Nut 7mm 644101
r 8 Nut 6-32 644601
r 2 Nut 8-32 644800
r 4 Washer 8mm x 14mm (Pot) 645101
r 4 Washer Fiber 645404
r 2 Lockwasher #6 INT 646600
r 2 Lockwasher #8 EXT 646828
r 1 Lug Solder #8 661002
r 1 Fuse Holder 663000
r 4 Bredblox 4-pin 665204
r 2 Terminal Male Cr imp 666010
r 2 Terminal Female Crimp 666011
r 1 Label (XK-550K) 723501
r 1 Manual 753550K
r 5 Insulator Mica 780002
r 5 Insulator Washer 780101
r 1 Silicon Grease 790004
r 6” Wire #20 Red Stranded 813210
r 2.5’ Wire #22 Bare Wire 845000
r 1 Line Cord 862105
r 2” Shrink T ubing 3/16” 890120
r 1” Shrink T ubing 1/4” 890701
r 2” Shrink T ubing 1/2” 891101
r 2” Shrink T ubing 3/4” 899110
r 1 Solder Tube 9ST4A

Screw Identification

Phillips AB Screw 4-40 / #6 Thread Cutting Screw Standard Screw

(Type 23)

Flat Head Screw

-2-

PARTS VERIFICA TION

Before beginning the assembly process, first familiarize yourself with the components and this instruction book.
Ver ify that all par ts are present. This is done best by checking off each item in the parts list.

RESISTORS CAPACITORS

Trim Pot

Pot

Discap Mylar

Electrolytic (Lytic)

(Radial)

IC

SEMICONDUCTORS

INTEGRATED CIRCUIT

Diode

Transistor

IDENTIFYING CAPACITOR VALUES

Capacitors will be identified by their capacitance value in pF (picofarads) or µF (microfarads). Most capacitors
will have their actual v alue printed on them. Some capacitors may hav e their value printed in the following man­ner.

Second Digit

First Digit

Multiplier
Tolerance

The above value is 10 x 1,000 = 10,000pF or .01µF
The letter K indicates a tolerance of +

10%

The letter J indicates a tolerance of +5%

For the No. 01234589
Multiply By 1 10 100 1K 10K 100K .01 0.1

Multiplier

Note: The letter “R” may be used at times to
signify a decimal point; as in 3R3 = 3.3

IDENTIFYING RESISTOR VALUES

Use the following information as a guide in properly identifying the value of resistors.

BAND 1

1st Digit

Color Digit
Black 0
Brown 1
Red 2
Orange 3
Yellow 4
Green 5
Blue 6
Violet 7
Gray 8
White 9

BAND 2

2nd Digit

Color Digit
Black 0
Brown 1
Red 2
Orange 3
Yellow 4
Green 5
Blue 6
Violet 7
Gray 8
White 9

Multiplier

Color Multiplier
Black 1
Brown 10
Red 100
Orange 1,000
Yellow 10,000
Green 100,000
Blue 1,000,000
Silver 0.01
Gold 0.1

Resistance

Tolerance

Color Tolerance
Silver +10%
Gold +

5%

Brown +

1%

Red +

2%

Orange +

3%

Green +

.5%
Blue +.25%
Violet +.1%

Bands

1 2

Multiplier

Tolerance

-3-

CONSTRUCTION

Introduction

Assembly of your XK-550 Digital/Analog Trainer Kit will prove to be an exciting project and give you much satisfaction and personal
achievement. If you have experience in soldering and wiring techniques, then you should have no problem with the assembly of this kit.
Care must be given to identifying the proper components and in good soldering habits. Above all, take your time and follow these easy
step-by-step instructions. Remember, “An ounce of prevention is worth a pound of cure”. Avoid making mistakes and no problems will
occur.

CAUTION: WEAR SAFETY GLASSES WHEN ASSEMBLING THIS KIT.
Assemble Components

In all of the following assembly steps , the components must be installed on the top side of the PC board unless otherwise indic ated. The
top legend shows where each component goes. The leads pass through the corresponding holes and the board is turned to solder the
component leads on the foil side. Solder immediately unless the pad is adjacent to another hole which will interfere with the placement
of the other component. Cut excessive leads with a diagonal cutter. Then, place a check mark in the box provided next to each step to
indicate that the step is completed. Be sure to save the extra leads for use as jumper wires if needed.

Soldering

The most important factor in assembling your digital / analog trainer is good soldering techniques. Using the proper soldering iron is of
prime importance. A small pencil type soldering iron of 25 - 40 watts is recommended.The tip of the iron must be kept clean at all
times and well tinned. Many areas on the PC board are close together and care must be given not to for m solder shor ts. Size and
care of the tip will eliminate problems.

For a good soldering job, the areas being soldered must be heated sufficiently so that the solder flows freely. Apply the solder simulta­neously to the component lead and the component pad on the PC board so that good solder flow will occur. Be sure that the lead
extends through the solder smoothly indicating a good solder joint. Use only rosin core solder of 60/40 alloy.
DO NOT USE ACID CORE SOLDER! Do not blob the solder over the lead because this can result in a cold solder joint.

1. Solder all components from
the copper foil side only.
Push the soldering iron tip
against both the lead and the
circuit board foil.

Component Lead

Soldering Iron

Circuit Board

Foil

2. First apply a small amount of
solder to the iron tip. This
allows the heat to leave the
iron and onto the foil.
Immediately apply solder to
the opposite side of the con­nection, away from the iron.
Allow the heated component
and the circuit foil to melt the
solder.

Solder

Soldering Iron

Foil

Example 1

Poor solder connections occur
when the lead is not heated
sufficiently. The solder will not
flow onto the lead as shown.T o
correct. reheat the connection
and, if necessary , apply a small
amount of additional solder to
obtain a good connection.

Solder does not flow onto the
lead. A hard rosin bead sur­rounds and insulates the con­nection.

Poor solder
connection

Mount Part

Soldering iron posi­tioned incorrectly.

Example 2

A solder bridge occurs when
solder runs between circuit
paths and creates a short cir­cuit. This is usually caused by
using too much solder. To cor­rect this, simply drag your sol­dering iron across the solder
bridge as shown.

4. Here is what a good solder
connection looks like. Cut
off excess leads.

3. Allow the solder to flow
around the connection.
Then, remove the solder and
the iron and let the connec­tion cool. The solder should
have flowed smoothly and
not lump around the wire
lead.

Solder

Soldering Iron

Foil

Bend Leads to Hold Part Solder and Cut Off Leads

Foil Side

Rx - 100Ω 5% 1/4W Resistor

(brown-black-brown-gold)

þ

-4-

INTRODUCTION

The XK-550K Digital/Analog Trainer is divided into four separate kits: BB-550-A, PS-550-B, AN-550-C and DG­550D. Each bag of parts is clearly identified. Open only the kit called for in your procedure. DO NOT open any
other bag at this time. The first kit is the BB-550-A which contains only the bredboard. The bredboard will be
assembled to the front panel of the trainer during the assembly of the PS-550-B Power Supply. Read your
instructions carefully.

POWER SUPPLY

The XK-550K has five built-in power supplies which will satisfy most design needs. This includes two variable
power supplies giving up to +20 volts and -20 volts at .5 amp. Below 15V, the current available is 1 amp. Three
fixed power supplies give you +12VDC, -12VDC or +5VDC at 1 amp each. These fixed voltages are the most
commonly used voltages for design work. All supplies are regulated to within 150mV. This means that you can
increase the current draw from no load to .5 amp and the voltage will change less than 150mV. All supplies are
also short circuit protected by using integrated circuit regulator devices.

ANALOG TRAINER SECTION FUNCTION GENERATOR

The analog trainer contains a complete function generator capable of producing sine, square and triangle wa v e­forms. The frequency of the generator is continuously variable from one hertz to over 100,000 hertz in five
steps. A fine tuning control makes the selection of any frequency easy. The output voltage amplitude is vari­able between 0 to 15Vpp. The output impedance is approximately 330 ohms.

DIGIT AL TRAINER SECTION

The digital trainer has the necessary functions to do your digital experiments. They consist of a clock genera­tor, two no-bounce switches, eight LED indicator lamps and eight data switches.

POWER SUPPLY SPECIFICATIONS

Power Supplies:

• +1.25V to 20VDC @ .5 amp (1.25V to 15V @ 1 amp).

• -1.25 to -20VDC @ .5 amp (-1.25V to -15V @ 1 amp).

• +12V +

5% @ 1 amp.

• -12V +5% @ 1 amp.

• +5V +5% @ 1 amp.

• 30VAC center tapped @ 1 amp.

• Load regulation - all DC supplies less than .2V no load to .5A.

• Line regulation - all DC supplies less than .2V 105 to 135V.

• Hum and ripple - all DC supplies less than .01V RMS.

• Short protection - all DC supplies-inter nal IC ther mal cutoff.

• Fuse 1.25A 250V.

Variable Resistance (undedicated):

• 1KΩ Potentiometer

• 100KΩ Potentiometer

USERS DESCRIPTION OF FRONT PANEL CONTROLS

1) On/Off Switch - Allows power to be applied to all outputs. Switch will
light when on.

2) Fuse Holder - Easy access for replacement of 1.25A fuse.

3) Power Output Terminals - This provides 30VAC center tapped at
15VAC; also provides output terminal for positive and negative
variable voltages.

4) Variable Positive Voltage Control - Varies positive voltage from 1.25
to 20V at indicated output connector pin.

5) Variable Negative Voltage Control - Varies negative voltage from

-1.25V to -20V at indicated output connector pin.

6) Output terminals for 1K and 100K undedicated potentiometers.

7) 1KΩ undedicated potentiometer.

8) 100KΩ undedicated potentiometer.

1

2

3

4

5

6

7 8

-5-

INSTALL COMPONENTS TO PC BOARD

START HERE

ê

Figure B

Note: One side of the
bracket is longer.

Mount
this side to the PC board.
Mount the bracket to the
top legend side of the PC
board with a 4-40 x 1/4”
screw and fiber washer.

Bottom Left Corner of PC Board

Top Left Corner of PC Board

4-40 x 1/4”

Screw

Top Legend

Side of

PC Board

Fiber

Washer

Figure C

Mount down flush with PC board. The
value may be marked on the on the
back side of pot.

Cut off excess lead length after sol­dering.

Figure D

Bend the capacitor at a 45

o

angle before soldering.Cut off
excess leads.

Cut off tab

Figure A

Mount the connector as shown and solder the
pins of the connector.

PC Board

r S1 - 5-Pin Connector

(see Figure A)

r L-Bracket

(see Figure B)

r VR4 - 100KΩ Pot
r VR3 - 1KΩ Pot

(see Figure C)

r S3 - 3-Pin Connector
r S2 - 3-Pin Connector

(see Figure A)

r L-Bracket

(see Figure B)

r C8 - .1µF Mylar (104)

(see Figure D)

-6-

INSTALL COMPONENTS TO PC BOARD

START HERE

ê

Figure F

Cut a piece of bare wire long enough
so that 1/4” of wire passes through
each hole in the PC board after the
wire is formed.

Figure G

Diodes have polarity. Mount them
with the band as shown on the top
legend.

Band

Bottom Left Corner of PC Board

Figure E

These capacitors are polarized.
Be sure to mount them with the
“+” lead in the correct hole as
marked on the PC board. Mount
the capacitor lying flat on the PC
board as shown below.

(+)

(--)

r C11 - 100µF 25V

(see Figure E)

r R1 - 120Ω 5% 1/4W Resistor

(brown-red-brown-gold)

r C6 - .1µF Mylar (104)

(see Figure D)

r J28 - Jumper Wire

(see Figure F)

r J6 - Jumper Wire

(see Figure F)

r D12 - 1N4001 Diode
r D11 - 1N4001 Diode

(see Figure G)

r C14 - 100µF 25V Lytic
r C17 - 100µF 25V Lytic

(see Figure E)

r C10 - .1µF Mylar (104)

(see Figure D)

r R2 - 120Ω 5% 1/4W Resistor

(brown-red-brown-gold)

r J2 - Jumper Wire

(see Figure F)

r J3 - Jumper Wire

(see Figure F)

INSTALL COMPONENTS TO PC BOARD

START HERE

ê

Bottom Left Corner of PC Board

-7-

Figure H

Hold the bredblock down flush to
the PC board from the top legend
side and solder the metal pins in
place. Then, melt the plastic pins
with your soldering iron to hold the
plastic blocks in place, as shown.

Plastic Pins

Melt Pins

r VR1 - 2KΩ Pot
r VR2 - 2KΩ Pot

(see Figure C)

r B1 - 4 Pin Bredblox
r B2 - 4 Pin Bredblox
r B3 - 4 Pin Bredblox
r B4 - 4 Pin Bredblox

(see Figure H)

r C12 - 100µF 25V Lytic

(see Figure E)

r J26 - Jumper Wire
r J7 - Jumper Wire

(see Figure F)

r D15 - 1N4001 Diode
r D14 - 1N4001 Diode
r D13 - 1N4001 Diode

(see Figure G)

r C15 - 100µF 25V Lytic
r C16 - 100µF 25V Lytic

(see Figure E)

r J4 - Jumper Wire
r J1 - Jumper Wire

(see Figure F)

r C13 - 100µF 25V Lytic

(see Figure E)

-8-

INSTALL COMPONENTS TO PC BOARD

START HERE

ê

CONTINUE

ê

CONTINUE

ê

Bottom Right Corner of PC Board

Figure J

Diodes have polarity. Mount them with
the band as shown on the top legend.

Figure I

These lytics must be mounted hori­zontal to the PC board. Bend the
leads at right angles and then insert
the leads into the PC board with the
negative (--) lead and the positive
(+) lead in the correct holes as
marked on the PC board.

START HERE

ê

Top Right Corner
of PC Board

* Leftover wire will be used in

future sections.

Band

+

r C1 - 1000µF 35V Lytic
r C5 - 1000µF 35V Lytic

(see Figure I)

r C2 - 1000µF 35V Lytic
r C4 - 1000µF 35V Lytic

(see Figure I)

r C3 - 2200µF Lytic
Mount on foil side of PC board

Note the polarity

(see Figure I)

r D1 - 1N4001 Diode
r D2 - 1N4001 Diode
r D3 - 1N4001 Diode
r D4 - 1N4001 Diode
r D5 - 1N4001 Diode
r D6 - 1N4001 Diode
r D7 - 1N4001 Diode
r D8 - 1N4001 Diode
r D9 - 1N4001 Diode
r D10 - 1N4001 Diode

(see Figure J)

r L-Bracket

(see Figure B)

r C7 - .1µF Mylar (104)

(see Figure D)

r J5 - Jumper Wire *

(see Figure F)

r C9 - .1µF (104) Mylar

(see Figure D)

r L-Bracket

(see Figure B)

-9-

MOUNTING THE PC BOARD

Note: The holes in the two side panels have been punched differently. Be sure that you have the correct side

panel when mounting them to the PC board.

r Mount the PC board with four 4-40 x 1/4” screws (see Figure K). Do not tighten the screws.

r Place the top panel on top of the unit.Push the PC board up until the com-

ponents come through the top panel and tighten the screws.

Adjust the PC
board height
with a 4-40 x
1/4” screw

Figure KA

Note: From the foil side of the PC board,

inspect the edges to be sure that there
are no component leads shorting against
the side panels.

Figure K

MOUNT COMPONENTS TO THE SIDE PANELS

Mount U1, U3 and U5 to the left side panel as shown in Figure N. Insert the pins of each IC into the holes of
the PC board. Then, with the hardware shown in Figure M, attach each IC to the side panel. Solder the pins
of the ICs to the PC board.

r U3 - LM7805
r U1 - LM317
r U5 - LM337

-10-

Mount the solder lug to the panel, as shown in Figure N, using a 6-32 x 5/16” screw and 6-32 nut.
r Solder Lug

6-23 Nut

IC

* Silicone Grease

Mica

Side Panel

Insulator Washer

6-32 x 5/16” Screw

* Take a small amount of silicone grease from the
packet and apply it with a toothpick onto the back of
the ICs.

Mica

Figure M

Figure N

Figure L

-11-

WIRE THE TRANSFORMER TO THE PC BOARD

Cut the blue, red, white and yellow wires on the transformer so they are 3” long and strip the insulation off of
the ends to expose 1/4”of bare wire. Solder the wires to the PC board starting with the top yellow wire as shown
in Figure P.

r Yellow wire to point F on the PC board
r Blue wire to point A on the PC board
r Red wire to point C on the PC board
r White wire to point E on the PC board
r Red wire to point D on the PC board
r Blue wire to point B on the PC board
r Yellow wire to point G on the PC board

Yellow (F)
Blue (A)
Red (C)
White (E)
Red (D)
Blue (B)

Yellow (G)

Figure P

3”

Mount U2 and U4 to the right side panel as shown in Figure
O. Insert the pins of each IC into the holes in the PC board.
Then, with the hardware shown in Figure MA, attach each
IC to the side panel. Solder the pins of the ICs to the PC
board.

r U4 - LM7912
r U2 - LM7812

Mount the transformer with the black wires as shown in
Figure O. Use the two 8-32 x 3/8” screws, #8 lockwashers,
and 8-32 nuts.
r Transformer mounted

Right Side

U4

U2

7812

7912

Figure O

Black Wires

8-32 Nut

#8 Lock Washer

#8 Lock Washer

8-32 Nut

#8-32 x 3/8” Screws

Transformer

Note: Make sure that the transformer
does not touch U4.

6-23 Nut

IC

* Silicone Grease

Mica

Side Panel

Insulator Washer

6-32 x 5/16” Screw

* Take a small amount of silicone grease from the
packet and apply it with a toothpick onto the back of
the ICs.

Figure MA

Mica

Yellow (G)

Blue (B)

Blue (A)

Red (D)
White (E)
Yellow (F)

Red (C)

HOW TO INSTALL CONNECTORS ONTO TRANSFORMER WIRES

A connector will be placed in the primary wires of the transformer. This will allow you to remove the top panel
from the trainer. Follow the procedures below.

1. Cut a six inch length off of each black primary wire.

2. Strip the insulation off of each end of the six inch wires to expose 1/4” of bare wire.

3. Place one wire onto the female pin and crimp the outer crimp tabs with pliers over the insulation as shown
in Figure 1A.

4. Crimp the inner tabs with pliers onto the bare wire as shown in Figure 1B and then solder the wire to the pin.

5. Connect the other female pin to the other wire using the same procedures above.

A

B

Locking Tab

Female Pin

Solder

Outer

Crimp Tab

Inner
Crimp Tab

Female Housing

Figure 1

Figure 2

6. Insert the two pin/wire assemblies into the female housing as shown in Figure 2. Pull on the wire to check
that the pin is inserted all the way in. It should not pull out of the housing. The locking tabs should be bent
outward to hold the pin in the housing.

TRANSFORMER WIRES

1. Strip the insulation off of each of the black primary wires to expose 1/4” of bare wire.

2. Place the wire onto the male pin and crimp the outer crimp tabs with pliers over the insulation as shown in
Figure 3A.

3. Crimp the inner tabs with pliers onto the bare wire and then solder the wire to the pin as shown in Figure 3B.

4. Connect the other male pin to the other primary wire using the same procedures above.

5. Insert the two pin/wire assemblies into the male housing as shown in Figure 4. Pull on the wire to check that
the pin is inserted all the way in. It should not pull out of the housing.

6. Connect the male and female housing as shown in Figure 5. Note that the connector only fits together one
way.

7. To detach the connector, push down on the end of the lock arm and pull the two apart.

Figure 3

Figure 4

A

B

Locking Tab

Male Pin

Solder

Outer

Crimp Tab

Inner
Crimp Tab

Male Housing

Lock Arm

Figure 5

-12-

MOUNT COMPONENTS TO PANEL

r Push the illuminated switch into the hole in the top panel with the lugs as shown in Figure Q.
r Install the fuse holder with the side lug in the position shown in Figure Q. Fasten the fuse holder in place

with the nut as shown in Figure R. Unscrew the cap and insert the fuse into the holder.

Side

Lug

Fuse Holder

Illuminated Switch

Nut

Top Panel

Plastic Washer

Fuse Holder

Back Side - Lower

Right Corner

Figure Q

Figure R

r

There is a raised area on the back side of the top panel. Screw the spacer to the raised area by inserting a
4-40 x 1/4” flat head screw into the hole in the raised area from the top side of the panel (see Figure S).

r

When mounting the bredboard, use the holes shown in Figure Ta. Mount the plastic spacer with a 4-40 x 1/4” flat
head screw as shown in Figure S. Next, mount the bredboard with two #4 x 1/4” AB black screws from the back
side of the top panel as shown in Figure S. The negative (blue) stripe should be on top and the numbers read­ing from left to right should start with number 1 (see Figure Tb). CAUTION: Do not remove the paper backing
from the back of the bredboards. Do not over-tighten the black screws.

Spacer

4-40 x 1/4”

Flat Head

Screw

Top Panel

Bredboard

#4 x 1/4” AB Screws

Figure S

a

e

b

c

d

f

j

g

hi

1

5

10

ON

30VAC

+5

+12

--12

15VAC

OFF

15VAC

REGULATED

POWER SUPPLY

+

2

0

C

D

--

2

0

C

D

GND

Figure Tb

Figure T a

-13-

WIRE SWITCH AND FUSE HOLDER (see Figure U)

Fuse

r Slide the line cord bushing onto the line cord as shown in Figure U.
r Spread the three line cord wires apart 6” from the end.
r Strip the insulation off of both ends of the 6” red wire to expose 1/4” of bare wire. Pass the wire through the

1/2” diameter shrink tubing. Attach one end to the side lug on the fuse holder and then solder into place.

r Strip 1/4” of insulation off of the smooth edged line cord wire. Pass the smooth edged line cord wire through

the 1/2” diameter shrink tubing and attach to the end lug on the fuse holder, solder into place.

r Slide the shrink tubing over the fuse holder covering both lugs. Shrink the tubing for a snug fit. You may use

a hair dryer, heat gun (at lowest setting or you will melt the tubing) or the heat emitting from your soldering
iron (do not touch the tubing or the wires with the iron).

Switch

Disconnect the connector for the transformer.
r Pass the 6” strip of red wire (leading from the side lug of the fuse holder), the (A) and (B) black transformer

wire, and the ribbed line cord wire through the 3/4” diameter piece of shr ink tubing.

r

Cut the 2” section of 3/16” diameter shrink tubing in half to create two 1” sections. Slide a 3/16” diame­ter piece of shrink tubing over the loose end of the red wire. Attach the red wire to lug 1 on the switch
and then solder into place.

r Pass the black transformer wire labeled (B) through a 3/16” diameter piece of shr ink tubing. Attach the wire

to lug 2 on the switch and then solder into place.

r Slide the shrink tubing over lug 1 and lug 2 on the switch. Shrink the tubing into place.
r Strip the insulation off of the black transformer wire (A) and the ribbed edged line cord wire to expose 1/2” of

bare wire. Twist the two bare wires together. Pass the wires through the 1/4” diameter piece of shrink tub­ing. Attach the wires to lug 3 on the switch and solder into place. Slide the tubing over the lug. Shrink the
tubing into place.

r Slide the 3/4” diameter shrink tubing over the switch and shrink into place.
r Reconnect the connector for the transformer.

Switch Pin-out

1

2

3

Fuse Holder

Side Lug

6” Red Wire

1/2” Dia. Shrink Tubing

3/16” Dia. Shrink Tubing

(B) Black T r ansf ormer Wire

Female Connector

(A) Black T r ansf ormer Wire

Smooth Line Cord Wire

Ribbed Line Cord Wire

Green Line Cord Wire

Solder Lug

3/4” Dia. Shrink Tubing

1/4” Dia. Shrink Tubing

Switch

Figure U

-14-

Bushing

-15-

RESISTANCE ANALYSIS OF POWER SUPPLY

Static testing of the power supply circuits. Do not plug the power supply into the 120VAC power supply
source until all resistance readings check out. The values given below are approximate .

See Figure O for locations of testing points.

Resistance

From To Circuit Ohms Measured

1 Right Side Panel Ear th Ground less than 1Ω
2 3 On/Off Switch, Fuse Infinite (SW1 Off)
2 3 On/Off, Fuse 7Ω (SW1 On)
4 5 12V Secondary 1.5Ω
6 7 5V Secondary 1.2Ω
8 9 Variable Voltage 1.6Ω

10 GND 5-pin connector +12V Regulator Input greater than 20KΩ

11

(com) GND (VΩ)

(5-pin connector)

--12V Regulator Input greater than 20KΩ
12 GND (B1) +5V Regulator Input greater than 20KΩ
13 GND (B1) +Variable Regulator Input greater than 20KΩ

14

(com) GND (VΩ)

(5-pin connector)

--Variable Regulator Input greater than 20KΩ

25

(com) GND (VΩ)

(5-pin connector)

Voltage ADJ +20V Regulator

CCW <1Ω CW >1.4KΩ

26 GND (VΩ)

(5-pin connector)

Voltage ADJ -20V Regulator greater than 1.4KΩ
27 GND (5-pin connector) +5V Regulator GND less than 1Ω
28 GND (5-pin connector) +12V Regulator GND less than 1Ω
29 GND (5-pin connector) --12V Regulator GND less than 1Ω
10 15 +12V Regulator Input less than 1Ω
11 16 --12V Regulator Input less than 1Ω
12 17 +5V Regulator Input less than 1Ω
13 18 +Variable Regulator Input less than 1Ω
14 19 --Variable Regulator Input less than 1Ω
20 GND (5-pin connector) +Variable Regulator Output CCW 100Ω CW 2.12K
20 +20 (5-pin connector) +Variable Regulator Output less than 1Ω
21 GND (5-pin connector) --Variable Regulator Output CCW 100Ω CW 2.12K
21 --20 (5-pin connector) --Variable Regulator Output less than 1Ω
22 GND (5-pin connector) +5V Regulator Output greater than 5KΩ
22 B4 +5V Regulator Output less than 1Ω
23 GND (5-pin connector) +12V Regulator Output greater than 5KΩ
23 B3 +12V Regulator Output less than 1Ω
24 GND (5-pin connector) --12V Regulator Output greater than 5KΩ
24 B2 --12V Regulator Output less than 1Ω

5

15VAC (5-pin connector right)

15VAC less than 1Ω

4

15VAC (5-pin connector left)

15VAC less than 1Ω

«+

30% ²Note: meter lead polarity CCW - Counter Clockwise CW - Clockwise µVR1 & VR2 Adjustment

²

²

µ«
µ«

«

«

20A

2A COM VΩ

VΩ

COM

-16-

Locations for Testing Points

•••

21

19

26

•••

18

20

25

•••

22

27

17

5 pin connector left

5 pin connector +20

5 pin connector right
5 pin connector -20

GND

Ground

•••

29

16

24

•••

15

28

23

9

8

7

6

5

4

10

11

12

13

14

+20V

Pot

-20V

Pot

Plug of line cord

1

3

2

Figure O

B1

LM-7812 LM-7912

LM-7805 LM-317

LM-337

On test points 4 - 14
use the leads of the
diodes.

VOLTAGE ANALYSIS OF POWER SUPPLY

Proceed with the voltage analysis only if the resistance readings were satisfactory.

Place the top panel on the unit. If any capacitors are inserted backwards, the panel will shield you if
they explode. Make sure that the ON/OFF switch is in the OFF position. Plug the line cord into the 120VAC

power source. Tur n the unit on and let it sit for a few minutes. Turn OFF the ON/OFF switch and remove the
top panel, placing it along the left side of the trainer. Turn ON the ON/OFF switch and measure the voltage point
as listed in the chart below. The values given are approximate.

See Figure V for locations of the testing points.

From To Circuit Volts Volts Measured

15 GND +12V Regulator Input +21V
B3 GND +12V Regulator Output +12V
16 GND -12V Regulator Input -21V
B2 GND -12V Regulator Output -12V
17 GND +5V Regulator Input +12.5V
B4 GND +5V Regulator Output +5V
18 GND +20V Regulator Input +28V
25 GND Voltage ADJ +20V Regulator CCW 0V CW +18V
+20

5 pin connector

GND +20V Output

CCW +1.25V CW +20V
19 GND -20 Regulator Input -28V
26 GND Voltage ADJ -20V Regulator CCW 0V CW -18V

-20

5 pin connector

GND -20V Output CCW -1.25V CW -20V
15VAC 15VAC 30VAC 30VAC
5-pin 5-pin
connector connector
left right

«
«

«
«

« +

30%

CCW - Counter-Clockwise CW - Clockwise

r Turn unit off.

-17-

FUSE REPLACEMENT

1. Tur n the trainer off and unplug it from 120VAC power source.

2. Unscrew fuse holder cap and remove fuse.

3. Use only a 1.25A fuse. Larger fuses or other fuse bypass will void the war-

ranty of the trainer.

4. Place the new fuse into the fuse holder cap and screw it back into the holder.

5. Plug trainer into 120VAC power source and turn the unit on.

Place the top panel on top of the unit.

-18-

POWER SUPPLY TESTING

Plug the trainer into a 120VAC outlet and switch to the “ON”position (the power s witch should light). With a dig­ital voltmeter, measure the voltage outputs at the power blocks. The +12V should measure between 11.4 and

12.6 volts. The 5V supply should read between 4.75 and 5.25 volts. The -12V supply should read between -

11.4 and 12.6 volts.

Do not short the 15VAC output to ground.

Short the +12V, -12V and +5V supply to ground. They should tur n off and recover when the short is removed.
If you have a 25Ω 10 watt resistor, place it across the output terminal (2 watt resistor will work, but use it only
for a few seconds). The output of the 12V supply should not change more than .20 volts. Do the same on the
5V supply using a 10Ω 5 watt resistor. Again, the output should not change more than .20 volts. In making this
test, the voltmeter leads should be clipped to the terminal directly and no to the load leads. This is to prevent
errors due to voltage drop from contact resistance of the load.
Check the variable voltage supplies in the same manner. Set the output voltage between 10-15 volts. Place
the 25Ω 10 watt resistor across the output terminal. The voltage should stay within .20 volts of the no load volt­age.

TROUBLESHOOTING CHART

This chart lists the condition and possible causes of several malfunctions. If a par ticular par t is mentioned as
a possible cause, check that part to see if it was installed correctly. Also, check it and the parts connected to it
for good solder connections. Note: The values given in this troubleshooting chart are an approximation.

PROBLEM POSSIBLE CAUSE

Switch doesn’t light. 1. Check fuse and line cord.
Fuse blows when the unit is turned on. 1. Voltage supply shorted to GND. Use resistance analysis

chart to find shor t.

No or low voltage at positive variable 1. Measure for an AC voltage of 18VAC at anode of D7 & D9.
output. A. Transformer and/or secondary connection to PC

board defective

2. Measure for a DC voltage of 28VDC at pin 3 of U1 LM317.
A. Diodes D7, D9 in backwards or defective, check

capacitor C1.

3. Set the voltage for minimum 1.25VDC and measure pin 2

of U1.

A. Voltage adjusts only from 7.8 - 9.8V R1 open or

defective.

B. Voltage 27V, check VR1 connections.

No or low voltage at positive variable 1. Check that capacitor C1 1000µF is inserted in the correct
output with load. polarity.

2. Check ripple on pin 3 of U1. 8VP-P Max.
A. Capacitor C1, and/or diodes D7, D9 defective.

-19-

PROBLEM POSSIBLE CAUSE

No voltage at negative variable output. 1. Measure for an AC voltage of 18VAC at cathode of D8, D10.

A. Transformer and/or secondary connection to PC board

defective.

2. Measure DC voltage of -28VDC at pin 2 of U5 LM337.

3.

Set voltage for minimum -1.25VDC and measure pin 3 of U5.

A. Voltage adjusts only from -7.8 to -9.8V R2 open or

defective.

B. Voltage -27V, check VR2 connections.

No or low voltage at negative variable 1.Check to see if capacitor C5 1000µF is inserted in the
output with load. correct polarity.

2. Check ripple on pin 2 of U5. 6VP-P max.

A. Capacitor C5 and/or diodes D8, D10 defective.

No +12V at output. 1. Measure an AC voltage of 15VAC at anode of D1, D3.

A. Transformer and/or secondary connection to PC board

defective.

2. Measure for a DC voltage of 21VDC at pin 1 of U2 LM7812.

A. Diodes D1, D3 in backwards or defective, check

capacitor C1.

3. Measure for a DC voltage of 12VDC on pin 3 of U2.

A. U2 LM7812 defective or open ground.

No +12V at output with load. 1.Check capacitor C2 1000µF is inserted in the correct

polarity.

2. Check ripple on pin 1 of U2. 7VP-P Max.

A. Capacitor C2 or diodes D1, D3 defective.

No -12V at output. 1. Measure an AC voltage of 15VAC at anode of D2, D4.

A.Transformer and/or secondary connection to PC board

defective.

2. Measure for a DC voltage of -21VDC at pin 2 of U4 LM7912.

A. Diodes D2, D4 in backwards or defective, check

capacitor C4.

3. Measure for a -12VDC voltage on pin 3 of U4.

A. U4 LM7912 defective or open ground.

No -12V at output with load. 1. Check capacitor C4 is inser ted in the correct polarity.

2. Check ripple on pin 2 of U3. 7VP-P Max.

A. Capacitor C4 and/or diodes D1, D3 defective.

No +5VDC at output 1. Measure an AC voltage of 9VAC at anode of D5, D6.

A. Transformer and/or secondary connection to PC board

defective.

2. Measure for a DC voltage of 12VDC at pin 1 of U3 LM7805.

A. Diodes D5, D6 in backwards or defective, check

capacitor C3.

3. Measure for a 5VDC voltage on pin 3 of U3 LM7805.

A. U3 LM7805 defective or open ground.

No +5VDC at output with load. 1. Check that capacitor C3 is inser ted in the correct polarity.

2. Check ripple on pin 1 of U3. 4VP-P Max.

A. Capacitor C3 and/or diodes D5, D6 defective.

-20-

FINAL ASSEMBLY

If you are immediately going to build the remaining
sections, do not continue with the instructions on
this page and proceed to page 22.

r Fasten the front panel in place

with four #6 x 3/8” thread cutting
screws, as shown in Figure W.

r Fasten the PC board to the

spacer to the front panel
with a fiber washer and a
4-40 x 1/4” screw (from
Power Supply Section)
from the foil side of the
PC board, in the location
shown in Figure X.

r Fasten the pots to

the front panel with
an 8mm washer
and a 7mm nut, as
shown in Figure W.

r Turn the shafts on

the two switches fully
counter-clockwise. Push the
knobs onto the shafts so that the
line on the knob is in line with the end of
the circle on the front panel (see Figure Y). If
the knob is loose on the shaft, insert a screwdriv­er into the slot and expand the slot slightly (see Figure
Z).

Figure Y

Figure X

Knob

Nut 7mm

Washer 8mm

#6 x 3/8” Thread

Cutting Screws

#6 x 3/8” Thread

Cutting Screws

Knob

Nut 7mm

Washer 8mm

Figure W

4-40 x 1/4” Screw

Figure Z

-21-

INSTALL COMPLETED UNIT INTO CASE

r Latch the case lid down. Remove the protective backing from the case label. Stick the label in the depres-

sion in the middle of the case lid.

r Tie a knot in the line cord 12” from the switch. See Figure AA for the location of the line cord hole in the

case. Insert the line cord into the hole through the slot. To open up the slot, press down on one side of the
slot (see Figure BB). Inser t the bushing into the hole and pull on the line cord until the knot is snug against
the bushing.

r Inser t the unit into the case at a 45

O

angle, bottom edge first. Secure into place with four 6 x 3/8” chrome

screws in the corner holes of the panel.

r The line can be neatly stored in the bin shown in Figure AA. Gather up the line cord and inser t it into the

bin. Insert the line cord fastener into the slots to the hole in place, as shown in Figure CC.

Figure AA

Figure BB

Figure CC

-22-

CIRCUIT DESCRIPTION

The power supply features tw o v ariab le output v oltages and three fixed 12V , -12V and 5V variable output voltages are

1.25V to 20V and -1.25 to -20V at up to 1 ampere maximum current. All supplies are regulated to better than .2V
when going from no load to full load. Varying the input AC voltage from 105 to 135V will have practically no effect on
the output voltages. This is because of the specially designed ICs used in the XK-550 Digital/Analog Trainer. Severe
overloading or ev en shorting the output circuits will not damage the supplies. Special turn-off circuits in the ICs sense
the overload and turn off the output.

THE POSITIVE 1.25 TO 20V POWER SUPPLY

Figure 1 shows a simplified circuit diagram of the positive supply. It consists of a power transformer, a DC rec­tifier stage and the regulator stage.

TRANSFORMER

The transformer T1 serves two purposes. First, it reduces the 120VAC input
to 17VAC to allow the proper voltage to enter the rectifier stages. Second,
it isolates the power supply output from the 120VAC line. This prevents the
user from dangerous voltages should he or she be standing in a grounded
area.

AC T O DC CONVERTER

The AC to DC converter consists of diodes D1, D3 and capacitor C1.
Transformer T1 has two secondary windings which are 180 degrees out of
phase. The output at each winding is shown in Figure 2A and 2B.

Diodes are semiconductor devices that allow current to flow in only one
direction. The arrow in Figure 3 points to the direction that the current will
flow. Only when the transformer voltage is positive will current flow through
the diodes. Figure 3 shows the simplest possible rectifier circuit. This cir­cuit is known as a half-wave rectifier. Here the diode conducts only half of
the time when the AC wave is positive as shown in Figure 2C. Use of this
circuit is simple but inefficient. The big gap between cycles require much
more filtering to obtain a smooth DC voltage.

By the addition of a second diode and transformer winding we can fill in the
gap between cycles as shown in Figure 4. This circuit is called full-wave rec­tification. Each diode conducts when the voltage is positive. By adding the
two outputs, the voltage presented to capacitor C1 is more complete, thus
easier to filter, as shown in Figure 2E. When used in 60 cycles AC input
power, the output of a full wave rectifier will be 120 cycles.

Capacitor C1 is used to store the current charges, thus smoothing the DC
voltage. The larger the capacitor, the more current is stored. In this design,
1000µF capacitors are used, which allows about 5 volts AC ripple when one
amp is drawn.

Figure 1

Simplified diagram of positive power supply

120VAC

Input

17VAC 20VDC

1.25 - 15V
Regulated

Output

Transformer

120V to 17V

AC to DC

Converter

Voltage

Regulator

Figure 2

Figure 3

Figure 4

Voltage Waveform for Supply

A) Transformer

Winding AB

B) Transformer

Winding BC

C) Output of

diode D1.

D) Output of

diode D2.

E) Total of diodes

D1 & D2.

20

F) Output of capacitor C1

Ripple depends on load
current (expanded).

Half Wav e Rectifier

Full Wav e Rectifier

-23-

In practice, the current through the diodes is not as shown in Figure 2C.
Because capacitor C1 has a charge after the first cycle, the diode will not
conduct until the positive AC voltage exceeds the positive charge in the
capacitor. Figure 5 shows a better picture of what the current flow looks
like assuming no loss in the diode. It takes a few cycles for the voltage to
build up on the capacitor. This depends on the resistance of the winding
and the diode. After the initial start-up, there will be a charge and dis­charge on the capacitor depending on the current drawn by the output
load. Remember, current only flows through the diode when the anode is
more positive than the cathode. Thus, current will flow in short bursts as
shown in Figure 5.

The DC load current may be one ampere, but the peak diode current may be three times that. Therefore, the
diode rating must be sufficient to handle the peak current. The 1N4001 has a peak current rating of 10 amps.

REGULATOR CIRCUIT

The regulator circuit in the power supply consists of a LM-317 integrated circuit. This IC is specially designed
to perform the regulation function. Figure 6 shows a simplified circuit of how the LM-317 IC works.

Transistors Q1 and Q2 form a circuit known as a differential amplifier. The base
of transistor Q1 is connected to a stable 1.5V reference voltage. The base of
Q2 is connected to the regulator output circuit through a voltage divider net­work. The collector of transistor Q2 is connected to a current source. This basi­cally is a PNP transistor biased to draw about 1mA of current. Transistor Q2
sees the current source as a very high resistor of about 1 meg ohms. Thus, the
gain of transistor Q2 is extremely high.

Transistor Q5 is called the pass transistor. It controls the current reaching the
output. Transistor Q3 and Q4 are emitter followers. Their function is to raise the impedance of the pass tran­sistor. Note that transistors Q2, Q3, Q4, Q5 and resistor R1 form a closed loop. Also, note that the feedback
to the base of Q2 is negative, that is, when the base of Q2 goes positive, the output at emitter Q5 goes nega­tive. Now if the 2 volt output voltage goes down because of current drain at the output, the base of Q2 will drop,
forcing the collector voltage to go higher. This will br ing the output voltage back to 2 volts. This is the basis of
all negative feedback regulators.

Another feature of the LM-317 regulator if to protect the IC against ov erload and output shorts. If the IC is over­loaded, the junction of an overload transistor will overheat. A transistor will sense this overheating and shut
down transistor Q5.

The LM-317 IC is basically a 1.25 volt regulator. To be able to vary the output
from 1.25V to 20V, we stack the IC on the a DC voltage as shown in Figure 7.
When VR1 equals 0, the output voltage is 1.25 volts as determined by the LM­317 IC. Note that the voltage across VR1 will equal the 1.25 volts across R1,
therefore the output voltage will be 2.5 volts. When VR1 is 5 times R1, the out­put voltage is 6.25 volts . As you can see, v arying resistor VR1 will v ary the volt­age from 1.25 volts to 20 volts.

THE NEGATIVE VOLTAGE REGULATOR

The theory of the negative regulator is the same as the previously discussed positive regulator. The basic dif­ference is that diodes D1 and D3 are reversed, producing a negative voltage across capacitor C1. The LM-317
IC is designed to operate from a negative supply.

Figure 5

Figure 6

Figure 7

A) Transformer

Winding
B) Voltage C1
C) Current

through diodes

20V

Peak

20V

2V

Output
R1

R2

Divider

Q1

Q2

1.5V

Q3

Q4

Q5

Current
Source
Equalized
to 1 Meg.

1.25 - 15V

R1

VR1

LM-317

-24-

SCHEMATIC DIAGRAM - POWER SUPPLY SECTION

1

2

3

8

4

10

11

6

7

12

5

9

13

14

18

20

25

19

21

26

17

22

27

15

23

28

16

24

29

#

Test Point

REV-E

25V

2200µF

-25-

QUIZ - POWER SUPPLY SECTION

INSTRUCTIONS - Complete the following examination and check your answers carefully.

1. AC voltage is supplied to the rectifier stages by the .. .

r A. step-up transformer.
r B. step-down transformer.
r C. 1 to 1 transformer.
r D. AC to DC transformer.

2. The secondary windings of the transformer are . . .
r A. 90

O

out of phase.

r B. 180

O

out of phase.

r C. 270

O

out of phase.

r D. 320

O

out of phase.

3. Diodes allow current to flow . . .

r A. when the anode is more negative than the cathode.
r B. when the cathode is more positive than the anode.
r C. in one direction.
r D. when a negative or positive voltage is on the anode.

4. What circuit is more efficient for rectifying AC to DC?

r A. Har tley oscillator.
r B. Half-walf.
r C. Schmitt trigger.
r D. Full wave.

5. The DC voltage is smoothed by using a . . .

r A. half-wave rectification circuit.
r B. small value capacitor with a high voltage value.
r C. Large value capacitor.
r D. 90

O

out of phase.

6. An inefficient rectification circuit usually contains . ..

r A. large gaps between cycles.
r B. twice the AC voltage needed.
r C. more diodes.
r D. all of the above.

7. The maximum current that a diode can handle is determined by . . .

r A. the transformer’s current rating.
r B. the amount of AC ripple.
r C. three times the diode rating.
r D. peak current rating.

8. The LM-317 will shut down when . . .

r A. the output voltage is too high.
r B. no current is being drawn.
r C. the junction overheats.
r D. the output voltage drops to 1.25V.

9. The LM-317 regulator contains . ..

r A. a pass transistor.
r B. a constant current source.
r C. a differential amplifier.
r D. all of the above.

10. The LM-317 is basically . . .

r A. a 1.25V regulator.
r B. a 6.25V regulator.
r C. a 2.5V regulator.
r D. a negative voltage regulator.

Answers: 1. B;2. B; 3. C; 4. D; 5.C; 6.D; 7. D; 8. C; 9. A; 10. A

AN-550-C

XK-550 ANALOG KIT (AN-550-C) PARTS LIST

RESISTORS

QTY SYMBOL VALUE COLOR CODE PART #

r 2 R14, R44 100Ω 5% 1/4W brown-black-brown-gold 131000
r 1 R5 200Ω 5% 1/4W red-black-brown-gold 132000
r 2 R46, R47 330Ω 5% 1/4W orange-orange-brown-gold 133300
r 1 R12 1KΩ 5% 1/4W brown-black-red-gold 141000
r 1 R49 2KΩ 5% 1/4W red-black-red-gold 142000
r 2 R7, R11 4.7KΩ 5% 1/4W yellow-violet-red-gold 144700
r 1 R3 6.8KΩ 5% 1/4W blue-gray-red-gold 146800
r 1 R13 8.2KΩ 5% 1/4W gray-red-red-gold 148200
r 1 R10 10KΩ 5% 1/4W brown-black-orange-gold 151000
r 1 R6 12KΩ 5% 1/4W brown-red-orange-gold 151200
r 3 R4, R45, R48 22KΩ 5% 1/4W red-red-orange-gold 152200
r 1 R9 47KΩ 5% 1/4W yellow-violet-orange-gold 154700
r 1 R8 51KΩ 5% 1/4W green-brown-orange-gold 155100
r 1 VR8 100KΩ TRIM POT 191610
r 1 VR5 10KΩ POT 192531
r 2 VR6, VR7 100KΩ POT 192612

CAPACITORS

QTY SYMBOL VALUE DESCRIPTION PART #

r 1 C27 5pF (5) Discap 205010
r 1 C26 22pF (22) Discap 212210
r 1 C23 100pF (101) Discap 221017
r 1 C18 .001µF (102) Mylar 231017
r 1 C25 .0022µF (222) Discap 232216
r 1 C19 .01µF (103) Mylar 241017
r 1 C20 .1µF (104) Mylar 251017
r 1 C21 1µF 50V Electrolytic 261047
r 2 C22, C24 10µF 25V Electrolytic 271045

SEMICONDUCTORS

QTY SYMBOL VALUE DESCRIPTION PART #

r 2 D16, D17 1N4148 Diode 314148
r 2 Q1, Q3 2N3904 Transistor PNP 323904
r 1 Q2 2N3906 Transistor NPN 323906
r 1 U10 LF357 Integrated Circuit 330357
r 1 U6 XR2206 Integrated Circuit 332206

MISCELLANEOUS

QTY SYMBOL DESCRIPTION PART #

r 1 SW2 Switch Rotar y 12-pin 542206
r 1 SW3 Switch Rotar y 16-pin 542405
r 5 Knob Push-on 622009
r 3 Nut 7mm 644101
r 2 Nut 9mm 644102
r 3 Washer Flat 8mm 645101
r 2 Washer Flat 9mm 645103
r 1 U10 8-Pin IC Socket 664008
r 1 U6 16-Pin IC Socket 664016
r 2 B5, B6 4-Pin Bredblox 665204
r 1 Solder 9ST4A

-26-

-27-

INTRODUCTION - ANALOG SECTION

The Analog Section of your trainer contains a complete function generator capable of producing sine, square,
and triangle waveforms. The frequency of this generator can be continuously varied from 1 hertz to over
100,000 hertz in five steps: 10, 100, 1K, 10K, and 100K. A fine frequency control makes selection of any fre­quency in between easy. The amplitude of the waveforms are adjustable from 0-15Vpp. A waveform of func­tion generator capable of producing sine, square and triangle waveform outputs has a wide range of applica­tions in electrical measurements and laboratory instrumentation. This complete function generator system is
suitable for experimentation and applications by the student. The entire function generator is comprised of a
single XR-2206 monolithic IC and a limited number of passive circuit components.

SPECIFICATIONS

Waveforms - Sine, square, triangle and complementar y square.
Frequency - 1Hz to 100kHz in 5 steps continuously variable.
Fine frequency adjust - 10:1 approximate.
Amplitude variable 0-15 Vpp.
Output impedance 330 ohms: short protected.
DC offset change 10V from zero crossing.

USERS DESCRIPTION OF FRONT PANEL CONTROLS

1. WAVEFORM - Selects square, triangle or sine waveform at the FREQ output.

2. COURSE FREQUENCY - Selects five ranges of frequencies 10, 100, 1K, 10K and 100K her tz.

3. FINE FREQUENCY - Allows easy selection of desired frequency according to the frequency range.

4. AMPLITUDE - Controls the amplitude of the FREQ output signal from 0-15Vpp.

5. DC OFFSET - Controls the DC level of the FREQ output signal. The DC level may be varied 10 volts from
zero level.

6. CLK - A 4-pin output block for function generator’s square wave. The amplitude of the signal is 5Vpp and
frequency is dependent on WAVEFORM selection.

7. FREQ - A 4-pin output block for function generator’s signals, output is dependent on WAVEFORM selection
and frequency is set by COURSE FREQ control. The amplitude of the output is variable from 0-15Vpp.

1

2 3 4 5

6

7

CONTINUE

ê

INSTALL COMPONENTS TO PC BOARD

START HERE

ê

Figure A

Cut a piece of bare wire long
enough so that 1/4” of wire
passes through each hole in
the PC board after the wire is
formed (provided in the sec­ond package).

Figure B

Insert the IC socket into the PC
board with the notch in the
direction shown on the top leg­end. Solder the IC socket into
place. Insert the IC into the
socket with the notch in the
same direction as the notch on
the socket.

Socket

IC

Notch

Figure C

Mount the tran­sistor with the
flat side in the
direction shown
on the top leg­end.

-28-

Figure D

Electrolytics have a polarity mark­ing on them indicating the nega­tive (--) lead. The PC board is
marked to show the lead posi­tions.

Mount the capaci­tors horizontal to the
PC board. Bend the
leads at right angles
and then insert the
leads into the PC
board.

(+)

(--)

Polarity

Mark

Flat

r J9 - Jumper Wire

(see Figure A)

r C25 - .0022µF (222) Discap
r J10 - Jumper Wire

r J25 - Jumper Wire

(see Figure A)

r VR8 - 100KΩ Tr im P ot

(see Figure E)

r C26 - 22pF (22) Discap
r C23 - 100pF (101) Discap
r J11 - Jumper Wire

r J12 - Jumper Wire
r J13 - Jumper Wire

(see Figure A)

r U10 - 8-pin IC socket
r U10 - LF357 IC

(see Figure B)

r R8 - 51KΩ 5% 1/4W Resistor

(green-brown-orange-gold)

r R11 -

4.7KΩ

5%

1/4W Resistor

(yellow-violet-red-gold)

r C27 - 5pF (5) Discap

r R5 - 200Ω 5% 1/4W Resistor

(red-black-brown-gold)

r J8 - Jumper Wire

(see Figure A)

r R3 - 6.8KΩ 5% 1/4W Resistor

(blue-gray-red-gold)

r R4 - 22KΩ 5% 1/4W Resistor

(red-red-orange-gold)

r U6 - 16-pin IC socket
r U6 - XR2206 IC

(see Figure B)

r R49 - 2KΩ 5% 1/4W Resistor

(red-black-red-gold)

r Q3 - 2N3904 Transistor

(see Figure C)

r R10 - 10KΩ 5% 1/4W Resistor

(brown-black-orange-gold)

r C24 - 10µF 25V Lytic

(see Figure D)

r R7 - 4.7KΩ 5% 1/4W Resistor

(yellow-violet-red-gold)

r R9 - 47KΩ 5% 1/4W Resistor

(yellow-violet-orange-gold)

CONTINUE

ê

INSTALL COMPONENTS TO PC BOARD

START HERE

ê

Figure E

Mount the trim pot to the PC board as
shown below.

Figure EA

Bend the capacitors at a 45Oangle before
soldering it to the PC board.

Figure F

Hold the bredblox down flush
to the PC board from the top
legend side and solder the
metal pins in place. Then,
melt the plastic pins with your
soldering iron to hold the
bredblox down as shown. Re­tin the solder tip afterwards.

Figure G

Diodes have polarity. Mount with
band in the direction shown on the
PC board.

Plastic Pins

Melt Pins

-29-

Band

r B6 - 4 pin Bredblox

(see Figure F)

r D16 - 1N4148 Diode

(see Figure G)

r R14 - 100Ω 5% 1/4W Resistor

(brown-black-brown-gold)

r B5 - 4 pin Breadblox

(see Figure F)

r R12 - 1KΩ 5% 1/4W Resistor

(brown-black-red-gold)

r R44 - 100Ω 5% 1/4W Resistor

(brown-black-brown-gold)

r D17 - 1N4148 Diode

(see Figure G)

r J23 - Jumper Wire

(see Figure A)

r R48 - 22KΩ 5% 1/4W Resistor

(red-red-orange-gold)

r Q1 - 2N3904 Transistor

(see Figure C)

r R47 -

330Ω

5%

1/4W Resistor

(orange-orange-brown-gold)

r R46 - 330Ω 5% 1/4W Resistor

(orange-orange-brown-gold)

r R45 - 22KΩ 5% 1/4W Resistor

(red-red-orange-gold)

r J16 - Jumper Wire
r J15 - Jumper Wire
r J14 - Jumper Wire

(see Figure A)

r Q2 - 2N3906 Transistor

(see Figure C)

-30-

INSTALL COMPONENTS TO PC BOARD

START HERE

ê

Figure H

Mount down flush with
PC board. The value
may be marked on the
back side of pot.

Cut off excess lead
length after soldering.

Potentiometers

Switches

Figure

I

Mount
down
flush
with PC
board.
Note:
SW2

has 12 pins and SW3 has 16 pins.

CONTINUE

ê

Cut off

tab

Cut off

tab

r J18 - Jumper Wire

(see Figure A)

r R13 -

8.2KΩ

5%

1/4W Resistor

(gray-red-red-gold)

r J17 - Jumper Wire

(see Figure A)

r C18 - .001µF (102) Mylar

(see Figure EA)

r R6 - 12KΩ 5% 1/4W Resistor

(brown-red-orange-gold)

r VR6 - 100KΩ Pot

(see Figure H)

r VR5 - 10KΩ Pot

(see Figure H)

r VR7 - 100KΩ Pot

(see Figure H)

r SW2 - SW Rotary 12
Pin

(see Figure I)

r SW3 - SW Rotary 16
Pin

r C21 - 1µF 50V Electrolytic

(see Figure D)

r C22 - 10µF 25V Electrolytic

(see Figure D)

r C20 - .1µF (104) Mylar

(see Figure EA)

r C19 - .01µF (103) Mylar

(see Figure EA)

RESISTANCE ANALYSIS OF ANALOG SECTION

Static testing of the analog circuits. Do not plug in the power supply into 120VAC power source until all
resistance readings check out. The values given below are approximated.

SET SW3 TO SQUARE WAVE (refer to top panel

From To Circuit Ohms Resistance Measured

Pin 11 (U6) Pin 3 (U10) Square Wave VR5 CCW 12.3KΩ
Pin 11 (U6) Pin 3 (U10) Square Wave VR5 CW 6.7KΩ

SET SW3 TO TRIANGLE WA VE

From To Circuit Ohms Resistance Measured

Pin 2 (U6) Pin 3 (U10) Triangle Wave VR5 CCW 14.7KΩ
Pin 2 (U6) Pin 3 (U10) Triangle Wave VR5 CW 4.7KΩ
Pin 13 (U6) Pin 14 (U6) Triangle Wave Greater than 1KΩ

SET SW3 TO SINE WAVE

From To Circuit Ohms Resistance Measured

Pin 2 (U6) Pin 3 (U10) Sine Wave VR5 CCW 14.7KΩ
Pin 2 (U6) Pin 3 (U10) Sine Wave VR5 CW 4.7KΩ
Pin 13 (U6) Pin 14 (U6) Sine Wave 200Ω
Pin 3 (U6) GND (B1) Mult VR8 CCW < 10Ω
Pin 3 (U6) GND (B1) Mult VR8 CW 100KΩ
Pin 4 (U6) +12V (B3) VCC Less than 3Ω
Pin 7 (U6) -12V (B2) Fine Freq Adj VR7 CCW 108.2KΩ
Pin 7 (U6) -12V (B2) Fine Freq Adj VR7 CW 8.2KΩ
Pin 12 (U6) -12V (B2) GND Less than 3Ω

ª 30% CCW - Counter-Clockwise CW - Clockwise

ª

ª

ª
ª

ª

ª

VR8

U10

U6

-31-

1

2
3
4

1
2
3
4

8
7
6
5

5
6
7810

9

11

12

13

14

15

16

VOLTAGE ANALYSIS OF ANALOG SECTION

Proceed with the voltage analysis only if the resistance readings were satisfactory. The values given below
are approximate.

The following measurements will be taken from the copper side of the PC board. Tur n the unit on and place it
upside down.

See Figure J for locations of the testing points.

From To Circuit Volts Volts Measured

Pin 4 (U6) GND (B1) U6 Vcc +12V
Pin 12 (U6) GND (B1) U6 GND -12V
Pin 7 (U10) GND (B1) U10 Vcc +12V
Pin 4 (U10) GND (B1) U10 Vcc- -12V

TESTING THE FUNCTION GENERATOR

Note: Use the knobs when turning the switches.

TESTING THE SINE WA VE

1. Set your meter to the 200mV DC range.

2. Connect the red meter lead to the 4 pin breadbloc k mark ed FREQ and the b lac k lead wire to the 4 pin bread-

block marked GND.

3. Set the WAVEFORM knob to SINE, COARSE FREQ UENCY knob to 1K and the FINE ADJ and AMPLITUDE

knobs fully clockwise.

4. Set the DC offset to the middle position. Then, tur n on the trainer.

Turn unit right side up. Figure J

-32-

1
2
3
4
5
6
7810

9

11

12

13

14

15

16

1
2
3
4

8

7
6
5

U10

U6

12

4

4

7

-33-

5. Set VR8 fully clockwise from the copper side of the PC board, and

adjust the DC OFFSET knob until the meter reads 0 volts DC.

6. Set the meter to the 20 volts AC range and slowly turn VR8

counter-clockwise until the meter reads 5.5 volts AC.

Note: Adjusting the DC offset will affect the VAC readings.

TESTING THE TRIANGLE WA VEFORM

1. Switch the WAVEFORM knob to its triangle wave setting.

2. With the meter set to the 20 volts AC range, you should read about

6.3 volts AC.

TESTING THE SQUARE W A VEFORM

1. Switch the WAVEFORM knob to its square wave setting.

2. Set your meter to the 20 v olts A C range, y ou should now read about

12.5 volts AC.

Turn the unit off and unplug it from the AC outlet.

TROUBLESHOOTING CHART

This chart lists the condition and possible causes of several malfunctions. If a par ticular par t is mentioned as
a possible cause, check that part to see if it was installed correctly. Also, check it and the parts connected to it
for good solder connections.

PROBLEM POSSIBLE CAUSE

No wave for m at FREQ 1. Check voltage at pins 4 (+12V) and 12 (-12V) of U6.

2. Check for wave forms at pin 2 of U6 and pin 3 of U10.
A. Check R3-4, R7, R13, C18-22, C24, SW2-3, VR5 & VR7.

3. Measure voltage at pins 7 (+12V) and 4 (-12V) of U10.

4. Check R8, R9, R11, R14, R44-48, D16, D17, Q1 and Q2.

No sine, triangle or low amplitude 1. Check U6 pin 2 for wave form.

A. Check VR8, voltage to IC.

Saw wave in sine position 1. R5 wrong value.
Wave forms clip top or bottom 1. Measure voltage at pins 7 (+12V) and 4 (-12V).

2. Adjust VR8.

3. Check R7, R9, R11, R14, R44-49, D16-17 and Q2-3.

No CLK wave output or low amplitude 1. Check pin 11 of U6 for square wave.

A. Check Q2 shor ted to ground.
B. Check R10, R12 and Q3.
C. Defective IC.

No square wave or low amplitude 1.Check pin 11 of U6 for square wave.
(FREQ output) A. Check Q2 shorted to ground.

B. Check R3, R49, SW3.
C. Defective IC.

Outputs wrong frequency 1. Check C18-22, C24, R13, SW2 and VR7.
DC offset not working 1. Check voltage on VR6 for +12V and -12V; check R8.

Trim Pot Adjustment

-34-

Figure M

Figure N

Figure L

FINAL ASSEMBLY

If you are immediately going to build the remaining
section, do not continue with the instructions on
this page, proceed to page 35.

r Fasten the front panel in place with

four #6 x 3/8” thread cutting
screws, as shown in Figure K.

r Fasten the PC board to the

spacer to the front panel with
a fiber washer and a 4-40 x
1/4” screw from the foil
side of the PC board, in
the location shown in
Figure L.

r Fasten the pots to the

front panel with an 8mm
washer and a 7mm
nut, as shown in
Figure K.

r Turn the shafts on

the two switches
fully counter-clock­wise. Push the knobs
onto the shafts so that the
line on the knob is in line with the
“Squarewave” on the waveform control
and “10” on the Coarse Frequency control
(see Figure M).
If the knobs are loose on the shafts, insert a screw­driver into the slot and expand the slot slightly (see Figure
O).

r Tur n the shafts on the pots fully counter-clockwise. Push the knobs onto the shafts so that the line on the

knob is in line with the end of the circle on the front panel, as shown in Figure N.
If the knobs are loose on the shafts, insert a screwdriver into the slot and expand the slot slightly (see Figure
O).

Knob

Nut 7mm

Washer 8mm

#6 x 3/8” Thread

Cutting Screws

#6 x 3/8” Thread

Cutting Screws

Nut 8mm

Washer 9mm

Nut 8mm

Washer 9mm

Knob

Nut 7mm

Washer 8mm

Figure K

4-40 x 1/4” Screw

Figure O

WAVE FORM COARSE FREQ

AMPLITUDE

10

100

1K

10K

100K

-35-

CIRCUIT DESCRIPTION

The function generator frequencies are produced by an XR2206
integrated circuit. This IC is capable of producing high quality sine ,
square and triangle waveforms of high stability and accuracy. The
output wavefor m can be both amplitude and frequency modulated
by an external voltage. Figure P shows the block diagram of the
XR2206 IC.

The XR2206 is comprised of four functions blocks, a voltage con­trolled oscillator (VCO), an analog multiplier and sine shaper, a
unity gain buffer amplifier, and a set of current switches.

The VCO actually produces an output frequency proportional to an
input current. Across pins 5 and 6, a timing capacitor is switched
in to give 5 different ranges of frequencies via COARSE FREQ
switch. On pin 7, the FINE FREQ ADJ v ariable resistor controls the
actual frequency output. These two components form the RC time constants for the oscillator frequency.

The VCO produces a square w a v e signal. This square wave is sent to a shaper and converted into a sine wav e .

QUIZ - ANALOG SECTION

INSTRUCTIONS: Complete the following examination and check your answers carefully.

1. The analog multiplier is part of . . .

r A. the voltage controlled oscillator.
r B. unity gain buffer amplifier.
r C. four function blocks.
r D. timing capacitor circuit.

2. Increasing the current of the VCO will effect the . ..

r A. amplitude.
r B. DC offset.
r C. AM modulation.
r D. frequency.

3. The RC time constant is determined by . . .

r A. pins 5 and 6.
r B. voltage controlled oscillator.
r C. pin 7 and a variable resistor.
r D. components on pins 5, 6, and 7.

4. What pins on the 2206 IC are used to change the
sine wave to a saw wave?

r A. 5, 6
r B. 15, 16
r C. 13, 14
r D. 4, 12

5. Adjusting P4 from +12V to -12V effects . . .

r A. sine wave amplitude.
r B. modulation.
r C. frequency stability.
r D. DC offset.

6. Coarse frequency is set by .. .

r A. P6.
r B. capacitor C11 through C15.
r C. C21.
r D. P1 and SW9.

7. A 1 volt DC level on the FM input will . ..

r A. shift the frequency 1kHz.
r B. shift the frequency to DC.
r C. have no effect.
r D. shift the frequency 1MHz.

8. The square wave and CLK output are 180

o

out

of phase because . . .

r A. Q2 inverts the CLK output.
r B. Q1 inverts the square wave output.
r C. a negative voltage is applied to P5.
r D. pin 12 is tied to -12V.

9. Clipping of the sine wave outputs can be cor­rected by . . .

r A. P5.
r B. the DC offset pot.
r C. lowering the +5V power supply.
r D. none of the above.

10. The sync output produces . . .

r A. a sine wave.
r B. a saw wave.
r C. voltage spikes.
r D. a square wave.

Functional Block Diagram

Figure P

116
215

314
413
512
611
710
89

Symmetry

ADJ.

Waveform

ADJ.

Ground

Sync

Output

Bypass

FKS
Input

Timing

Resistor

Timing

Capacitor

V+

Mult. Out

Sine/Saw

Output

AM Input

+1

Multiplier

and

Sine

Shaper

VCO

Current

Switches

Answers: 1. C; 2.D; 3. D; 4. C; 5. D; 6.B; 7. C; 8. A; 9. D; 10.D

SCHEMATIC DIAGRAM - ANALOG SECTION

-36-

XK-550 DIGITAL KIT (DG-550-D) PARTS LIST

RESISTORS

QTY SYMBOL VALUE COLOR CODE PART #

r 8 R36 - R43 120Ω 5% 1/4W brown-red-brown-gold 131200
r 1 R15 220Ω 5% 1/4W red-red-brown-gold 132200
r 4 R16 - R19 1KΩ 5% 1/4W brown-black-red-gold 141000
r 16 R20 - R35 100KΩ 5% 1/4W brown-black-yellow-gold 161000

SEMICONDUCTORS

QTY SYMBOL VALUE DESCRIPTION PART #

r 1 U7 SN7403 IC 337403
r 8 D18 - D25 LED Diode (red) 350002
r 2 U8, U9 74HC04 IC 39HC04

MISCELLANEOUS

QTY SYMBOL DESCRIPTION PART #

r 10 SW4 - SW13 Slide Switch SPDT 541009
r 2 S4, S5 Connector 4 pin 591042
r 8 Spacer 1/4” #8 624124
r 2 Screw #4 x 1/4” Phillips AB 642430
r 3 U7 - U9 Socket IC 14 Pin 664014
r 12 B7 - B18 Bredboard 665204
r 1 Bredblox 99426

INTRODUCTION

The Digital Section is the fourth package of the XK-550K kit that you are building. The Digital Section of your
trainer contains all of the necessary functions to do your digital designs. They consist of a clock generator, two
no bounce logic switches, 8 LED indicator lamps and 8 data switches. We have also added a 730 tie point
Bredblox to your already existing 830 tie points, giving you a total of 1560 tie points to handle complex circuit
designs.

SPECIFICATIONS

• Data switches, eight DPDT, Hi 5V, low 0V.

• Logic switches, two no bounce with complementary output.
“On” voltage level 2.8V min., “Off” voltage level 1V max.
Input impedance 100KΩ.

• Eight LED readouts, 100KΩ input impedance.

• Clock frequency, 1Hz to 100kHz in 5 steps continuously variable.

• Clock amplitude, 5Vpp squarewave.

• Clock rise time, better than 100 nsec.

• Bredboard 730 tie points.

DG-550-D

-37-

-38-

USERS DESCRIPTION OF FRONT PANEL

1. OUTPUT TERMINALS - For all functions as stated. 4 pins per block.

2. TWO LOGIC SWITCHES - These are no bounce logic switches. Give one signal state change per move-
ment of switch.

3. INPUT TERMINALS FOR LOGIC INDICATOR LEDs - “A” input corresponds with “A” lamp, etc.

4. LOGIC INDICATORS - Eight LEDs.

5. EIGHT DATA SWITCHES - Lets output of 5V or 0V depending on position.

6. OUTPUT TERMINAL - For all functions as stated. 4 pins per block.

7. BREDBOARD - One bredboard containing 730 tie points.

1

2

3

4

5

6

7

INSTALL COMPONENTS TO PC BOARD

START HERE

ê

-39-

r R34 - 100KΩ 5% 1/4W Resistor

(brown-black-yellow-gold)

r R35 - 100KΩ 5% 1/4W Resistor

(brown-black-yellow-gold)

r R33 - 100KΩ 5% 1/4W Resistor

(brown-black-yellow-gold)

r R32 - 100KΩ 5% 1/4W Resistor

(brown-black-yellow-gold)

r R28 - 100KΩ 5% 1/4W Resistor

(brown-black-yellow-gold)

r R27 - 100KΩ 5% 1/4W Resistor

(brown-black-yellow-gold)

r R30 - 100KΩ 5% 1/4W Resistor

(brown-black-yellow-gold)

r R31 - 100KΩ 5% 1/4W Resistor

(brown-black-yellow-gold)

r R29 - 100KΩ 5% 1/4W Resistor

(brown-black-yellow-gold)

r R26 - 100KΩ 5% 1/4W Resistor

(brown-black-yellow-gold)

r R20 - 100KΩ 5% 1/4W Resistor

(brown-black-yellow-gold)

r R22 - 100KΩ 5% 1/4W Resistor

(brown-black-yellow-gold)

r R24 - 100KΩ 5% 1/4W Resistor

(brown-black-yellow-gold)

r R21 - 100KΩ 5% 1/4W Resistor

(brown-black-yellow-gold)

r R23 - 100KΩ 5% 1/4W Resistor

(brown-black-yellow-gold)

r R25 - 100KΩ 5% 1/4W Resistor

(brown-black-yellow-gold)

INSTALL COMPONENTS TO PC BOARD

START HERE

ê

-40-

Figure A

Mount the connector as shown and solder the
pins of the connector.

PC Board

r R43 - 120Ω 5% 1/4W Resistor

(brown-red-brown-gold)

r R42 - 120Ω 5% 1/4W Resistor

(brown-red-brown-gold)

r S5 - 4 pin connector

(see Figure A)

r R41 - 120Ω 5% 1/4W Resistor

(brown-red-brown-gold)

r R40 - 120Ω 5% 1/4W Resistor

(brown-red-brown-gold)

r R39 - 120Ω 5% 1/4W Resistor

(brown-red-brown-gold)

r R38 - 120Ω 5% 1/4W Resistor

(brown-red-brown-gold)

r S4 - 4 pin connector

(see Figure A)

r R37 - 120Ω 5% 1/4W Resistor

(brown-red-brown-gold)

r R36 - 120Ω 5% 1/4W Resistor

(brown-red-brown-gold)

CONTINUE

ê

INSTALL COMPONENTS TO PC BOARD

START HERE

ê

CONTINUE

ê

-41-

Figure C

Cut a piece of bare wire long
enough so that 1/4” of wire
passes through each hole in
the PC board after the wire is
formed (provided in the sec­ond package).

Figure D

Insert the IC socket into the PC board
with the notch in the direction shown
on the top legend. Solder the IC sock­et into place. Insert the IC into the
socket with the notch in the same
direction as the notch on the socket.

Socket

IC

Notch

Figure B

Mount with the flat side of the
LED as shown on the top leg­end side of the PC board.

Flat

Spacer

r U9 - 14-pin IC Socket
r U9 - 74HC04 IC

(see Figure D)

r U8 - 14-pin IC Socket
r U8 - 74HC04 IC

(see Figure D)

r J19 - Jumper Wire

(see Figure C)

r R15 - 220Ω 5% 1/4W Resistor

(red-red-brown-gold)

r J22 - Jumper Wire

(see Figure C)

r J21 - Jumper Wire

(see Figure C)

r J20 - Jumper Wire

(see Figure C)

r R18 - 1KΩ 5% 1/4W Resistor

(brown-black-red-gold)

r U7 - 14 pin IC socket
r U7 - 7403 IC

(see Figure D)

r J24 - Jumper Wire

(see Figure C)

r D25 - LED and Spacer

(see Figure B)

r J27 - Jumper Wire

(see Figure C)

r D24 - LED and Spacer

(see Figure B)

r D23 - LED and Spacer

(see Figure B)

r D22 - LED and Spacer

(see Figure B)

r D21 - LED and Spacer

(see Figure B)

r D20 - LED and Spacer

(see Figure B)

r D19 - LED and Spacer

(see Figure B)

r D18 - LED and Spacer

(see Figure B)

r R19 - 1KΩ 5% 1/4W Resistor

(brown-black-red-gold)

r R16 - 1KΩ 5% 1/4W Resistor

(brown-black-red-gold)

r R17 - 1KΩ 5% 1/4W Resistor

(brown-black-red-gold)

INSTALL COMPONENTS TO PC BOARD

INSTALL COMPONENTS TO FRONT PANEL

r

Interlock the bredboard to the bottom edge of the existing bredboard on the top panel as shown in Figure
H. Fasten the bredboards in place with two #4 x 1/4”AB black screws from the back side of the panel. Use
the holes on the 9426 bredboard as shown in Figure G. CAUTION: Do not remove the paper backing from
the bredboard.

9830

9426

Top Panel

Bredboards

#4 x 1/4” Screws

Use these

holes

Figure G

Figure H

-42-

START HERE

CONTINUE

Figure E

Hold the bredblox down flush to the PC
board from the top legend side and sol­der the metal pins into place. Then, melt
the plastic pins with your soldering iron to
hold the plastic blocks in place as shown.

Figure F

Mount the switch onto the legend side
of the PC board as shown. Flip the
board over and solder the part into
place. Be sure to keep the three sol­dered sets of leads separate as
shown.

Plastic Pins

Melted Pins

Switch

Legend side
of PC board

Foil side of
PC board

Solder

Note: The 9418 and the power strip 9408 make
up the 9426 bredboard.

r SW4 - Slide Switch r SW7 - Slide Switch r SW10 - Slide Switch
r SW5 - Slide Switch r SW8 - Slide Switch r SW11 - Slide Switch
r SW6 - Slide Switch r SW9 - Slide Switch r SW12 - Slide Switch

(see Figure F) r SW13 - Slide Switch

r B7 - 4-pin Bredblox r B11 - 4-pin Bredblox r B15 - 4-pin Bredblox
r B8 - 4-pin Bredblox r B12 - 4-pin Bredblox r B16 - 4-pin Bredblox
r B9 - 4-pin Bredblox r B13 - 4-pin Bredblox r B17 - 4-pin Bredblox
r B10 - 4-pin Bredblox r B14 - 4-pin Bredblox r B18 - 4-pin Bredblox

(see Figure E)

-43-

RESISTANCE ANALYSIS OF DIGITAL SECTION

Place the top panel onto the unit. Static testing of the digital section circuits. Do not plug the power supply into
a 117 volt power source until all of the resistance readings check out. The values given below are approxi-

mate.

From To Switch Position Ohms Resistance Measured

SW1 GND In down position less than 1Ω
SW2 GND In down position less than 1Ω
SW3 GND In down position less than 1Ω
SW4 GND In down position less than 1Ω
SW5 GND In down position less than 1Ω
SW6 GND In down position less than 1Ω
SW7 GND In down position less than 1Ω
SW8 GND In down position less than 1Ω
SW1 GND In up position greater than 3KΩ
SW2 GND In up position greater than 3KΩ
SW3 GND In up position greater than 3KΩ
SW4 GND In up position greater than 3KΩ
SW5 GND In up position greater than 3KΩ
SW6 GND In up position greater than 3KΩ
SW7 GND In up position greater than 3KΩ
SW8 GND In up position greater than 3KΩ
SW1 +5V In up position less than 300Ω
SW2 +5V In up position less than 300Ω
SW3 +5V In up position less than 300Ω
SW4 +5V In up position less than 300Ω
SW5 +5V In up position less than 300Ω
SW6 +5V In up position less than 300Ω
SW7 +5V In up position less than 300Ω
SW8 +5V In up position less than 300Ω

LOGIC SW

DATA SWITCHES

XX

YY

SW1 SW2 SW3 SW4 SW5 SW6 SW7 SW8

-44-

VOLTAGE ANALYSIS OF DIGITAL SECTION

Plug the power supply into a 117 volt power source. The values given below are approximate.

From To Switch Position Volts Volts Measured

X GND In up position 5V
X GND In up position less than 1V
Y GND In up position 5V

Y GND In up position less than 1V
SW1 GND In up position 5V
SW2 GND In up position 5V
SW3 GND In up position 5V
SW4 GND In up position 5V
SW5 GND In up position 5V
SW6 GND In up position 5V
SW7 GND In up position 5V
SW8 GND In up position 5V

X GND In down position less than 1V

X GND In down position 5V

Y GND In down position less than 1V

Y GND In down position 5V
SW1 GND In down position less than 1V
SW2 GND In down position less than 1V
SW3 GND In down position less than 1V
SW4 GND In down position less than 1V
SW5 GND In down position less than 1V
SW6 GND In down position less than 1V
SW7 GND In down position less than 1V
SW8 GND In down position less than 1V

LOGIC SW

DATA SWITCHES

XX

YY

SW1 SW2 SW3 SW4 SW5 SW6 SW7 SW8

High Positions

SW1-8

XX

YY

-45-

TESTING THE DIGITAL SECTION

TESTING THE LOGIC INDICATOR FUNCTION

There are eight logic indicators which you will be checking out. Put a wire to the 5V power supply and touch
the “A” logic indicator test pin. The “A” LED should light up. Remove the wire and the LED should go out. Do
the same for the B, C, D, E, F, G and H pins.

TESTING THE LOGIC SWITCHES

There are two logic switches and four conditions to be checked out. Connect a wire from the “X” test pin to the
“A” logic indicator test pin. Connect another wire to the “X” test pin to the “B” test pin.

Apply power and note that the “A”LED indicator should be lit when the logic switch is in the “X” position and the
“B” LED should light and the “A” LED not light. Check the “Y” logic switch in the same manner.

TESTING THE DA T A SWITCHES

There are eight data switches to be checked. The output of the switches are 5V or ground depending on the
position. Connect a wire to the SW1 test pin and the “A” test pin. The “A” LED should light when the switch is
placed toward the top of the case. Repeat the same test on SW2, SW3, SW4, SW5, SW6, SW7 and SW8.

r Unplug the unit from the AC outlet.

DIGIT AL TROUBLESHOO TING CHART

PROBLEM POSSIBLE CAUSE

No +5V on data switch terminals. 1. Measure for a DC voltage of +5V across R15.

A. Check R15, J19, J23 and J13.
B. Switch shor ted to ground.

LED doesn’t light 1. Check that the LED is in correctly.

2. Check the input and output resistors.

3. Measure input for +5V and output at ground.
A. Shor t to ground or defective IC.

LED always on 1. Measure for zero voltage voltage at input pin.

A. Pin shor ted or defective IC

2. Measure voltage to output pin for +5V.
A. Pin shor ted or defective IC.

Logic switch terminal always high 1. Check that input resistor is grounded.

A. Bad ground connection or switch.

2. Measure for +5V on R16 - R19.
A. Check resistor.

3. Defective IC.

-46-

FINAL ASSEMBLY

r Fasten the front panel in place with four #6 x 3/8”thread

cutting screws, as shown in Figure I.

r Fasten the PC board to the spacer to

the front panel with a fiber washer
and a 4-40 x 1/4” screw (from
Power Supply Section) from the
foil side of the PC board, in the
location shown in Figure J.

r Fasten the pots to the front

panel with an 8mm wash­er and a 7mm nut, as
shown in Figure I.

r Turn the shafts on the two

switches fully counter­clockwise. Push the
knobs onto the
shafts so that the
line on the knob is
in line with the
“Squarewave” on
the waveform control
and “10” on the Coarse
Frequency control (see Figure
K).
If the knobs are loose on the shafts,
insert a screwdriver into the slot and expand
the slot slightly (see Figure M).

r Tur n the shafts on the pots fully counter-clockwise. Push

the knobs onto the shafts so that the line on the knob is in line
with the end of the circle on the front panel, as shown in Figure L.
If the knobs are loose on the shafts, insert a screwdriver into the slot and expand the slot slightly (see Figure
M).

Knob

Nut 7mm

Washer 8mm

#6 x 3/8” Thread

Cutting Screws

#6 x 3/8” Thread

Cutting Screws

Nut 8mm

Washer 9mm

Nut 8mm

Washer 9mm

Knob

Nut 7mm

Washer 8mm

Figure I

Figure K

Figure L

Figure J

4-40 x 1/4” Screw

Figure M

10

100

1K

10K

100K

WAVE FORM COARSE FREQ

-47-

INSTALL COMPLETED UNIT INTO CASE

r Tie a knot in the line cord 12” from the switch location. Feed the line cord between the cross bracket and

the PC board.

r Locate the line cord hole in the case (see Figure N). Inser t the line cord into the hole through the slot. To

open up the slot, press down on one side of the slot (see Figure O). Insert the bushing into the hole and
pull on the line cord until the slot is snug against the bushing.

r Inser t the unit into the case at a 45

O

angle with the bottom edge first. Secure the unit into place with four 8

x 1/2” black screws in the corner holes of the panel.

r The line can be neatly stored in the bin shown in Figure N. Gather up the line cord and insert it into the bin.

Insert the line cord fastener into the slots to the hole in place, as shown in Figure P.

r Place the label on the front of the case with the top of the label facing away from the handle, as shown in

Figure Q.

Figure N

Figure O

Figure P

Figure Q

-48-

CIRCUIT DESCRIPTION - DIGITAL SECTION

THE DATA SWITCHES

There are eight data switches labeled SW1 through SW8. The circuit is very simple. To perform the desired
functions, there is a double throw doub le pole s witch, wired as a single pole double throw. One end is connected
to the 5V, the other to ground and the center lug is connected to the output.

THE LOGIC SWITCHES

The logic switches are also DPDT switches wired as SPST s witches . The logic switches perform the same func­tion as the data switches. That is, they produce high or low states. But there is one big diff erence. When switch­ing the data switches, many pulses may be produced due to bouncing of the contacts.

In the logic switches, only one pulse is produced at the IC output no mat­ter haw many times the contacts bounce. This is extremely important if
you are producing pulses for counting circuits. Figure R shows the wiring
of the logic switch. The two NAND gates are connected so that when the
X input is grounded, the X output goes high. Opening and closing the
ground at X will not change the output. Only when X is grounded will the
output change to low. Thus, only one output change is produced with one
movement of the X switch. There are two outputs from each logic switch.
There are two outputs from each logic switch, X and X or Y and Y.

THE LOGIC INDICATORS

There are eight logic indicators. Figure S shows the circuit. It consists of a 74HC04 IC. When the input is over

2.8V, the output of the IC will be low, dr a wing current through the LED indi­cator. The 120Ω resistor limits the current in the LED to less than 20mA.
When there is no connection to the input of the logic indicators, the two
100KΩ resistor bias the input to GND. This insures that the LED will be
off.

Figure R

Figure S

SCHEMATIC DIAGRAM

-49-

-50-

QUIZ - DIGITAL SECTION

INSTRUCTIONS: Complete the following examination, check your answers carefully.

1.The logic switches consist of . . .

r A. two NAND gates and an SPST switch.
r B. three OR gates.
r C. two NAND gates and a DPDT switch.
r D. one OR gate.

2.When the logic switch is thrown .. .

r A. the contacts do not bounce.
r B. a single transition is produced at the NAND gate output.
r C. a multiple transition is produced at the NAND gate output.
r D. none of the above.

3. If the X output is high, opening and closing the ground at X switch will . . .

r A. cause the X output to go low.
r B. cause the X output to go high.
r C. cause the X output to go from high to low.
r D. none of the above.

4.The logic indicator LED lights up when . . .

r A. input voltage is 2V.
r B. input voltage is greater than 2.8.
r C. the IC output is high.
r D. all of the above.

5.The logic switches use . . .

r A. single pole single throw switches.
r B. double pole double throw switches wires as single pole double throw switches.
r C. two pole 5 position rotary switches.
r D. 4 pole 3 position rotar y switches.

6.The 100KΩ resistor on the logic indicator input . . .

r A. divides the input voltage in half.
r B. bias the input to +5V.
r C. bias the input to GND.
r D. tur n on the LED.

7. When the logic switch is in the X position . . .

r A. X is high, X is low.
r B. X is high, X is high.
r C. X is low, X is high.
r D. X is low, X is low.

8. When the data switch is up and connected to the logic indicator . . .

r A. the switch output is greater than 2.8V.
r B. the switch output is GND.
r C. the LED will be out.
r D. none of the above.

9.The +5VDC power for the digital section comes from a . . .

r A. 7805 IC.
r B. 7905 IC.
r C. 5V battery.
r D. 7812 IC.

10. If pin 4 on U7B is high . . .

r A. pin 3 is low.
r B. pin 1 is low.
r C. pin 2 and 6 are high.
r D. pin 5 is high.

Answers: 1. C; 2.B; 3. D; 4. B; 5. B; 6.C; 7. A; 8. A; 9. A; 10.B

Elenco Electronics, Inc.

150 W. Carpenter Ave .

Wheeling, IL 60090

[phone]

Web Site: http://www.elenco.com

e-mail: [e-mail]