Tektronix 1502 User manual

_ Addendum to the 1502 and 1503 Time Domain Reflectometer Instruction
manuals.
TEKTROND©
WATERTIGHT
SEALING PROCEDURES
for
1502/1503 TIME DOMAIN
REFLECTOMETERS
INSTRUCTION MANUAL
Tektronix, Inc.
P.O. Box 500
Beaverton, Oregon 97077
070-2178-00 First Printing JULY 1976

WARRANTY
Tektronix warrants that this product is free from defects in materials
and workmanship. The warranty period is one (1) year from the date
of shipment. Tektronix will, at its option, repair or replace the
product if Tektronix determines it is defective within the warranty
period and if it is returned, freight prepaid, to a service center
designated by Tektronix. .
Tektronix is not obligated to furnish service under this warranty:
a. torepair damage resulting from attempts by personnel other
than Tektronix representatives to install, repair, or service the
product;
b. to repair damage resulting from improper use or from
connecting the product to incompatible equipment;
c. if personnel other than Tektronix representatives modify the
hardware or software.
There is no implied warranty of fitness for a particular purpose.
Tektronix is not liable for consequential damages.
Copyright © 1976 Tektronix, Inc. All rights reserved.
Contents of this publication may not be reproduced in any
form without the written permission of Tektronix, Inc.
Products of Tektronix, Inc. and its subsidiaries are
covered by U.S. and foreign patents and/or pending
patents.
TEKTRONIX, TEK, SCOPE-MOBILE, and Tort are reg-
istered trademarks of Tektronix, Inc. TELEQUIPMENT is
a registered trademark of Tektronix U.K. Limited.
Printed in U.S.A. Specification and price change
privileges are reserved.

REV A JUN 1980
TABLE OF CONTENTS
LIST OF ILLUSTRATIONS
PURPOSE
MATERIALS
SPECIAL TOOLS
ASSEMBLY PROCEDURES
Step 1. Preparation of subpanel for further assembly.
Step 2. Install the holder for the Battery Level Indicator. .
Step 3. Install the seal for the Power Switch.
Step 4. Install washers for the Fuseholders.
Step 5. Install the Pushbutton seals in the Subpanel.
Step 6. Installation of rubber seals in Subpanel grooves.
Step 7. Installation of Implosion shield.
Step 8. Preparation of Frontpanel.
Step 9. Bonding of Plug-in Compartment seal.
Step 10. Bonding of washer to BNC type connector.
Step 11. Install pushbuttons and their shaft assemblies.
Step 12. Attach Subpanel to the three Frame Sections.
Step 13. Install Frontpanel on Subpanel.
Step 14. Install Fuseholders in Frontpanel.
Step 15. Install Fusehoider Caps.
Step 16. Install Battery Meter.
Step 17. Install FOCUS and INTENSITY controls.
Step 18. Install FINE POSITION control.
Step 19. Install! DISTANCE METER.
Step 20. Install ZERO REFERENCE control.
Step 21. Install the Record control.
Step 22. Install the GAIN (1502), or O-dB SET (1503).
Step 23. Partial installation, Main Circuit Board.
Step 24. Install cam switch inserts.
Step 25. Finish installation, Main Circuit Board.
Step 26. Install Power Switch Shaft.
Step 27. Install POSITION and FINE POSITION knobs.
Step 28. Install ZERO REFERENCE knob and CHECK pushbutton.
Step 29. Install FOCUS and INTENSITY knobs.
Step 30. Seal Battery Pack.
Step 31. Frontpanel jacks on X-Y Module.
Step 32. Thumbscrews for X-Y Module.
Step 33. Latch assemblies for Front Cover.
1502/1503 SEALING
Page
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1502/1503 SEALING
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure
Figure 10.
Figure 11.
Figure 12.
Figure 13.
Figure 14.
Figure 15.
Figure 16.
Figure 17.
Figure 18.
Figure 19.
Figure 20.
Figure 21.
Figure 22.
Figure 23.
Figure 24,
Figure 25.
Figure 26.
Figure 27.
Figure 28.
Figure 29,
Figure 30.
Figure 31,
Figure 32.
Figure 33.
Figure 34.
Figure 35.
ONOaAh
NH
+
co
LIST OF ILLUSTRATIONS
Subpanel, identification of parts for Steps 1 through 7.
Rubber seals, edge sealing for Subpanel.
Detail of implosion shield sealing.
Front Panel, identification of parts for assembly Steps 8 through 26.
Detail of Plug-In Compartment seal.
Detail of BNC Connector and Washer.
Detail of Pushbuttons and their Shafts.
Detail of Subpanel and screw-hole sealing.
Detail of Fusehoider installation.
Detail of Fushoolder Caps.
Application of sealant to Battery Meter.
Alignment of Battery Meter.
Application of sealant to FOCUS and INTENSITY controls.
Application of sealant to FINE control bushing.
Application of sealant to FINE control nut.
Installation of Distance Meter.
Application of sealant to ZERO REFERENCE control bushing.
Application of sealant to ZERO REFERENCE control nut.
Application of sealant to CAMERA/RECORD toggle-switch bushing.
Application of sealant to CAMERA/RECORD toggle-switch nut.
Installation of rubber Cap-Seal on CAMERA/RECORD toggle-switch.
Application of sealant to the GAIN or the 0-dB SET control bushing.
Detail showing lubrication and sealing for the variable resistor.
Lubrication of the O-rings and sealing for the Cam Switches.
Installation of the POWER SWITCH.
Lubrication of POSITION control knob.
Installation of knob on shaft.
Lubrication of ZERO REFERENCE knob.
installation of knob on ZERO REFERENCE control.
Lubrication of FOCUS and INTENSITY control knobs.
Sealing of Battery Pack screwholes.
Application of dielectric type compound.
Detail of front panel jacks.
Detail of X-Y Module thumbscrews.
Sealing of Latch Assembly screw-holes.

1502/1503 SEALING
PURPOSE
This addendum includes only those assembly procedures that are concerned with
making a 1502 or 1503 a watertight instrument.
MATERIALS
Tektronix Part No. Description Notes _
006-2302-00 Dow Corning No. 3144 This Room Temperature Vulcan-
Adhesive Sealant izing agent (RTV) is used to form
watertight gaskets. (After appli-
006-1171-00 Dow Corning No. 3145 cation, allow 24 hours curing
Adhesive Sealant time.)
252-0199-00 Dow Corning No. 3140 This RTV agent is used where the
Coating application requires a sealant
more fluid than the No. 3144 seal-
ant. (Allow 24 hour curing time.)
006-0315-00 Dow Corning No. 4 This compound is used in the
Silicone Dielectric Battery Pack assembly.
Compound
006-2475-00 Dow Corning No. 1204 Used as a primer for No. 3144
Primer sealant applications.
006-2207-00 General Electric Used as a waterproof lubricant.
No. G-661 Silicone
grease
006-0500-00 Acetone Cleaning Agent.
006-0034-00 lsopropy! Alcohol Cleaning Agent.
REV A JUN 1980

1502/1503 SEALING
ASSEMBLY PROCEDURES
NOTE
In the following assembly steps, the part being discussed is identified by its
Tektronix Part Number (TPN) and its location in the Mechanical Parts List
(MPL) of the Instruction Manuals for the 1502 and 1503. Example, in Step 17
the Front Subpanel is being discussed. In the 1502 manual, the part is
identified as TPN 426-1187-01 and is listed in the MPL under Fig. & Index No.
3-26, In the 1503 manual, the part is identified as TPN 426-1187-02 and is
listed in the MPL under Fig. & Index No. 3-26.
MOUNTING SCREW
IMPLOSION SHIELD
POWER SWITCH SEAL
BATTERY METER HOLDER
OSC)
He
MAIN SEAL
FRONT DISTANCE METER
PUSHBUTTON SEAL
PUSHBUTTON SHAFT
FUSEHOLDER, WASHER
Figure 1. Subpanel, identification of parts for steps 1 through 7. ,

STEP 1.
STEP 2.
STEP 3.
STEP 4.
STEP 5.
1502/1503 SEALING
Preparation
of
the
Subpanel
for
further
assembly
(see
Figure
1)
A.
SUBPANEL,
FRONT
(1) 1502 TPN 426-1187-01, MPL Item 3-26.
(2) 1503 TPN 426-1187-02, MPL Item 3-26.
B. Procedure.
(1) Clean entire Subpanel with isopropyl alcohol.
install
the
Holder
for
the
Battery
Level
Indicator
in
the
Subpanel
A.
HOLDER
(1)
1502
TPN
352-0243-00,
MPL
Item
2-54.
(2)
1503
TPN
352-0243-00,
MPL
Item
2-57.
B.
Procedure.
(1)
Insert
the
holder
into
the
Subpanel.
(2)
This
item
does
not
require
the
application
of
a
sealing
compound
Install
the
seal
for
the
Power
Switch
in
the
Subpanel
A.
SEAL,
SWITCH
(1) 1502 TPN 348-0422-00, MPL Item 2-52.
(2) 1503 TPN 348-0422-00, MPL Item 2-55.
B. Procedure.
(1) Clean mating surface of seal with acetone.
(2)
Coat
mating
surface
of
seal
with
No.
3144
sealant.
(3) Install seal in Subpanel.
install
washers
for
the
Fuseholders
in
the
Subpanel
A.
WASHER,
FLAT
(2
ea.)
(1)
1502
TPN
210-1246-00,
MPL
Item
2-49.
(2)
1503
TPN
210-1246-00,
MPL
Item
2-51.
B.
Procedure.
(1)
Clean
the
washers
with
acetone.
(2)
Coat
the
mating
surfaces
of
the
washers
with
No.
3144
sealant.
(3)
Insert
the
washers
in
the
Subpanel.
install the Pushbutton seals in the Subpanel.
A. SEAL, PUSHBUTTON
(1)
1502
TPN
348-0409-01,
MPL
Item
2-51,
and
TPN
348-0409-03,
MPL
Item 2-50.
(2)
1503
TPN
348-0409-01,
MPL
Item
2-53,
TPN
348-0409-02,
MPL
Item
2-54, and TPN 348-0409-04, MPL Item 2-52.
B. Procedure.
(1)
Clean
mating
surfaces
of
seals
with
acetone.
(2)
Coat
mating
surfaces
with
No.
3144
Sealant.
(3) Install seals in subpanel.

1502/1503 SEALING
G-661
LUBRICANT
FRONT
SIDE
RUBBER Seal (FRONT)
.
Coe
ew
.e
OUTSIDE
EDGE
wet
eg
he
3 & % 3 ,
ses « . . e?
~ sear Be
vo 7 ah
~ ot -," weds
BGs e
Syl
- 5 ca cee ee
NO.
3140
_-~
ey
Reta
he
SEALANT
“
Pty
ey
ye
RUBBER Seal (REAR)
G-661
LUBRICANT
REAR
SIDE
Figure 2. Rubber Seals, edge sealing for subpanel.
STEP 6. Installation of rubber seals in two grooves located on the outer (see
Figures 1 and 2) edges of the front and rear sides of the Subpanel.
A. SEAL, RUBBER (2 ea.)
(1) 1502 TPN 348-0477-00, MPL !tem 2-55.
(2) 1503 TPN 348-0477-00, MPL Item 2-58.
B. Procedure.
(1) Clean the rubber seais with acetone.
(2) Apply a film of No. 3140 sealant to the inner surface of each groove
See Figure 2. Do not apply the sealant to the other surfaces of the
grooves. No. 3140 is more fluid than No. 3144 and can be applied with
a hypodermic type applicator.
(3) Place a seal in each groove. Trim each seal to a length such that its
ends butt together. Apply a film of No. 3140 sealant to the Butt joint.
(4) Before installing the instrument in a cabinet, lubricate the outer
edges of the seals as shown in Figure 2.

REV A JUN 1980
1502/1503 SEALING
NO. 3144
SEALANT
RETAINER
REMOVE EXCESS SEALANT
SN SHIELD
SUBPANEL
Figure
3.
Detail
of
implosion
shield
sealing.
STEP
7.
Install
the
implosion
shield
and
its
retainer
on
the
Subpanel
(see
Figures 1 and 3)
A. SHIELD, IMPLOSION
(1) 1502 TPN 337-2206-00, MPL Item 2-94.
(2) 1503 TPN 337-2206-00, MPL Item 2-91.
B. RETAINER
(1) 1502 TPN 343-0610-00, MPL Item 2-93.
(2) 1503 TPN 343-0610-00, MPL Item 2-90.
C. Procedure.
(1)
Clean
the
retainer
and
the
implosion
shield
mounting
area
of
the
Subpanel with acetone.
(2) Remove the protective paper from the implosion shield.
(3)
Position
the
shield
on
the
Subpanel
and
form
a
continuous
bead
of
No.
3144
sealant,
approximately
.090
inch
in
diameter,
around
the
shield/Subpanel interface.
(4)
Position
the
retainer
over
the
bead
of
sealant
and
press
into
place.
NOTE
(1)
Pressing
the
retainer
should
cause
some
of
the
sealant
to
appear
outside
the
retainer
area,
see
Figure
3.
Failure
of
the
sealant
to
appear
at
any
point
around
the
retainer
is
an
indication
of
inadequate
sealing.
(2)
When
performing
this
step,
assure
that
the
shield
makes
flush
contact
with
the
subpanel,
see
Figure
3.
(5)
After
a
curing
time
of
approximately
4
hours,
use
a
small
wooden
dowel,
such
as
a
Q-tip
handle,
and
remove
the
excess
sealant
that
is
visible
between
the
shield
and
retainer.

1502/1503 SEALING
BATTERY METER PLUG-IN SEAL
POWER SWITCH SHAFT
\ POWER anne
DISTANCE
VARIABLE RESISTOR
FRONT PANEL INSTI: mp/DIV wurt/er
wo © 30 x ss Xt
200 ~ - s
al 2
CABLE vocus rramatry “ . mm, i
CAUTION
abet ir
SECORD
ats 2
s+
-_ =
“¢ ed
| or
1502
CABLE
Be
NN
7.
.
A
=a
BNC
CONNECTOR
CAM
SWITCH
SHAFT INSERT
VARIABLE RESISTOR
VARIABLE RESISTOR
TOGGLE SWITCH
FUSEHOLDER
Figure 4. Front Panel, identification of parts for assembly steps 8 through 26.
STEP 8. Preparation of Front Panel for assembly (see Figure 4)
A. FRONT PANEL
(1) 1502 TPN 333-1991-00, MPL Item 2-47.
(2) 1503 TPN 333-2003-00, MPL Item 2-49.
(3) 1503 Option 5, TPN 333-2123-00, MPL Item 2-49.
B. Procedure.
(1) Clean mating surface of front panel with acetone.
(2) Coat mating surface of panel with No. 1204 primer. Allow 2 hour
curing time.
PANEL
SEAL
NO. 3144 G-661
SEALANT LUBRICANT
Figure. 5. Detail of Plug-in Compartment seal.

1502/1503 SEALING
STEP 9. Bonding of Plug-in Compartment seal to Front Panel (see Figure 5)
A. SEAL, PLUG-IN
(1) 1502 TPN 348-0421-00, MPL Item 2-48.
(2) 1503 TPN 348-0421-00, MPL Item 2-50.
B. Procedure.
(1) Clean mating surfaces of seal with acetone.
(2) Apply No. 3144 sealant to mating surface of seal.
(3) Position seal on rear side of Front Panel.
(4) Clamp Sealin place.
(5) Allow 2 hour curing time. Remove clamp, inspect seal bond, and
remove any excess sealant. Allow an additional 22 hour curing time.
NOTE
Be sure seal is bonded securely to edge of pane! as well as rear
surface of panel.
NO. 3144
SEALANT
G-661
LUBRICANT
SL
BNC CONNECTOR
WASHER
Figure. 6. Detail of BNC Connector and Washer.
STEP 10. Bonding of washer to BNC type connector that is located on the
Main Circuit Board Assembly (see Figure 6)
A. CONNECTOR, RECEPTACLE
(1) 1502 TPN 131-1097-00, MPL item 2-125.
(2) 1503 TPN 131-1691-00, MPL Item 2-170.
B. WASHER, FLAT SPONGE
(1) 1502 TPN 210-1251-00, MPL Item 2-111.
(2) 1503 TPN 210-1251-00, MPL Item 2-94.
C. Procedure.
(1) Clean mating surfaces of BNC Connector and Washer with acetone.
Allow to dry.
(2) Apply No. 1204 Primer to mating surface of BNC connector. Allow 2
hour curing time. .
(3) Coat Mating surface of washer with No. 3144 sealant.
(4) Assemble washer on BNC connector.
REV
A
JUN
1980
9

1502/1503 SEALING
10
SHAFT
a
a
NO. 3144 PANEL
SEALANT
DETENT
Figure 7. Detail of Pushbuttons and their Shafts.
STEP 11. install pushbuttons and their shaft assemblies (see Figure 7)
A. PUSHBUTTONS
(1) 1502 TPN 366-1620-11, MPL Item 2-8;
TPN 336-1620-10, MPL Item 2-9;
TPN 336-1620-08, MPL Item 2-10;
TPN 366-1620-02, MPL Item 2-11.
(2) 1503 TPN 366-1620-11, MPL Item 2-7;
TPN 366-1620-09, MPL Item 2-8;
TPN 366-1620-02, MPL Item 2-9;
TPN 366-1620-03, MPL Item 2-10;
TPN 366-1620-04; MPL Item 2-11;
TPN 366-1620-05, MPL Item 2-12;
TPN 366-1620-06, MPL Item 2-13;
TPN 366-1620-07, MPL Item 2-14.
B. EXTENSION SHAFT
(1) 1502 TPN 384-1101-00, MPL 2-1114, (4 ea.).
(2) 1503 TPN 384-1101-00, MPL 2-97 (8 ea.).
C. Procedure.
(1) Clean the mating surfaces of each shaft with isopropyl alcohol.
(2) Insert the shafts into the pushbutton seals. See Figure 7.
(3) Apply bead of No. 3144 sealant to each shaft/seal interface.
(4) Install pushbuttons in their respective locations.
FRAME
SUB
PANEL
NO. 3144
REMOVE
EXCESS
SEALANT SEALANT
Figure 8. Detail of Subpanei screwhole sealing.

1502/1503 SEALING
STEP 12. Attach Subpanel to the three Frame Sections (see Figure 8)
A. FRAME SECTIONS
(1) 1502: Left, TPN 426-1184-00, MPL Item 3-116; Center, TPN 426-1185-
00, MPL Item 3-117; Right, TPN 426-1186-00, MPL Item 3-118.
(2) 1503: Left, TPN 426-1184-00, MPL Item 3-115; Center, TPN 426-1185-
00, MPL Item 3-116; Right, TPN 426-1186-00, MPL Item 3-117.
B. SCREWS
(1) TPN 213-0718-00, MPL Item 3-27 (1 ea.).
(2) TPN 213-0227-00, MPL Item 3-28 ( 5 ea.).
C. Procedure.
(1) Fill the countersunk screw holes on the Subpanel with No. 3144
sealant. See Figure 8.
(2) Attach the Subpanel to the three Frame sections. The decorative
screw is installed in the upper-left corner of the subpanel.
STEP 13. Install Front Panel on Subpanel
A. Procedure.
(1) Apply G-661 lubricant to the rear surface of the Plug-in Seal, 348-
0421-00, and to the two Fuse Holder Seals, 210-1246-00.
(2) Place Front Panel on the Subpanel.
SUBPANEL
SILICONE SPONGE
WASHER
FUSEHOLDER
NEOPRENE WASHER NUT
ALUMINUM
FRONT PANEL WASHER
Figure 9. Detail of Fuseholder installation.
STEP 14. Install Fuseholders in Front Panel (see Figure 9)
A. FUSEHOLDERS
(1) 1502 TPN 352-0362-00, MPL Item 2-24.
(2) 1503 TPN 352-0362-00, MPL Item 2-26.
B. Procedure.
(1) Install the two Fuseholders as shown in Figure 9.
(2) Tighten the retaining nut on the fuseholder until the Front Panel is
pulled flush with the Subpanel.
CAUTION
Do not overtighten.
11

1502/1503 SEALING
12
WASHER
CAP
NO. 3144
SEALANT
Figure 10. Detail of Fusehoider Caps.
STEP 15. Install Fuseholder Caps (see Figure 10)
A. WASHERS
(1) 1502 TPN 210-1245-00, MPL Item 2-25.
(2) 1503 TPN 210-1245-00, MPL Item 2-27.
B. Procedure.
(1) Clean washers and Fuseholder Caps with ispropyl alcohol.
(2) Apply No. 3144 sealant to one surface of a washer and place the
washer in one of the Fuseholder Caps. Repeat for the other washer
and cap.
(3) Insert the caps in the Fuseholders and press to ensure the washers
are fully seated.
(4) Remove the caps, inspect, and remove any excess sealant.
(5) Apply a film of G-661 lubricant to exposed surface of washer.
(6) Insert fuse (see Electrical Parts List for correct value) into cap and
install cap with fuse in the Fuseholder.
NO. 3144
SEALANT
Figure 11. Application of sealant to Battery Meter. Figure 12. Alignment of Battery Meter.

1502/1503 SEALING
STEP 16. Install Battery Meter (see Figures 11 and 12)
A. METER
(1) 1502 TPN 149-0031-00, MPL Item 2-53.
(2) 1503 TPN 149-0031-00, MPL Item 2-56.
B. Procedure.
(1) Apply a thin bead of No. 3144 sealant to the junction of the bezel and
meter canister (see Figure 11).
(2) Install Meter in Front Panel with markings aligned as shown in Figure
12.
BARREL
NO. 3144
SEALANT
noo
BUSHING
SHAFT
Figure, 13. Application of sealant to FOCUS and INTENSITY controls.
STEP
17.
Install
the
FOCUS
and
INTENSITY
controls
(see
Figure
13).
A.
RESISTOR,
VARIABLE
(2 ea.).
(1) 1502 TPN 311-0690-01, MPL Item 2-38 and Item 2-41.
(2) 1503 TPN 331-0690-01, MPL Item 2-40 and Item 2-43.
(3)
These
two
variable
resistors
are
used
for
FOCUS
and
INTENSITY
control and are listed in the Electrical Parts List.
. Procedure.
(1) Unscrew the bushing part of the resistor assembly and pack the
barrel/shaft interface with G-661 lubricant.
(2) Screw the bushing into the resistor assembly.
(3) Forma bead of No. 3144 sealant around the fillet area of the bushing.
(4) Use the washers and nuts supplied and install these two controls in
the Front Panel.
13

1502/1503 SEALING
14
NO. 3144
SEALANT
-—
Figure. 14. Application of sealant to FINE control bushing.
STEP 18. Install FINE POSITION control (see Figures 14 and 15).
A. RESISTOR, VARIABLE
(1) 1502 TPN 311-0678-00, MPL Item 2-30.
(2) 1503 TPN 311-0678-00, MPL Item 2-32.
(3) The part number for this variable resistor is listed in the Electrical
Parts List.
B. Procedure.
(1) Form a bead of No. 3144 sealant around the bushing threads as
shown in Figure 14.
(2) install nut on bushing as shown in Figure 15.
(3) Form a bead of No. 3144 sealant at the interface of the nut and
bushing as shown in Figure 15.
(4) Use washer and nut supplied and install the control in the Front
Panel.
NUT
NO. 3144
SEALANT
— peg .250 +.015
Figure. 15. Application of sealant to FINE control nut.

1502/1503 SEALING
LOCK WASHER
NUT
FLAT WASHER
NO.
3144
—
TN
SUBPANEL
RESISTOR
ASSEMBLY
“O” RING
METER
Figure, 16, Installation of Distance Meter.
STEP 19. Install the DISTANCE METER in the Front Panel (see Figure 16).
A. RESISTOR, VARIABLE
(1) 1502 TPN 311-1755-01, MPL Item 2-44.
(2) 1503 TPN 311-1755-01, MPL Item 2-46.
(3) This variable resistor is listed in the Electrical Parts List as circuit
number R0271.
B. Procedure.
(1) Insert the resistor assembly in the Front Panel.
(2) Form a bead of No. 3144 sealant at the interface of the resistor
assembly and the Front Panel. The bead should include the threads
and anti-rotation lug.
(3) Use the flat-washer, lock-washer, and nut to secure the resistor
assembly to the Front Panel.
C. Distance Indicator Knob Replacement.
(1) If it is necessary to attach a knob shell/lens assembly to the
DISTANCE indicator, form a bead of No. 3144 adhesive sealant
TPN 006-1171-00 at the interface of the DISTANCE indicator and
the knob shell.
REV
A
JUN
1980
15

1502/1503 SEALING
16
LUG
NO. 3144
SEALANT
——
Figure. 17. Application of sealant to ZERO REFERENCE control bushing.
STEP 20. Install the ZERO REFERENCE control in the Front Panel (see
Figures 17 and 18)
A. RESISTOR, VARIABLE
(1) 1502 TPN 311-1806-00, MPL Item 2-27.
(2) 1503 TPN 311-1806-00, MPL Item 2-49.
(3) This variable resistor is listed in the Electrical Parts List.
B. Procedure.
(1) Form a bead of No. 3144 sealant around the threads of the bushing as
shown in Figure 17.
2)
Flatten or remove the anti-rotation lug on the resistor housing.
3) Install nut as shown in Figure 18.
4) Form a bead of No. 3144 sealant around the nut/bushing interface.
5) Use attaching hardware and install resistor in Front Panel.
(
(
(
(
NUT
NO. 3144
SEALANT
= i
_. etfs 250 +.015
Figure. 18. Application of sealant to ZERO REFERENCE contro! nut.

1502/1503 SEALING
NO. 3144
SEALANT
_=>
fl
fi
Figure 19. Application of sealant to RECORD toggie-switch bushing.
NUT (FLUSH WITH SW. BODY)
NO. 3144
SEALANT
c —)
Figure 20. Application of sealant to RECORD toggile-switch nut.
n
*-RUBBER SEAL
-——) |
nD
Figure 21. Installation of rubber Cap-Seal on RECORD toggle-switch.
STEP 21. Install the Record control (see Figures 19, 20, and 21)
A. SWITCH, TOGGLE
(1) 1502 TPN 260-1727-00, MPL Item 2-20.
(2) 1503 TPN 260-1727-00, MPL Item 2-23.
B. CAP, TOGGLE SWITCH, SEAL
(1) 1502 TPN 200-1744-00, MPL item 2-21.
(2) 1503 TPN 200-1744-00, MPL Item 2-24.
C. Procedure.
(1) Form a bead of No. 3144 sealant around the bushing/switch body
interface as shown in Figure 19.
(2) Install nut that was supplied with the switch, as shown in Figure 20.
(3) Form a bead of No. 3144 sealant around the bushing/nut interface as
shown in Figure 20.
(4) Use attaching hardware and install the toggie switch in the Front
Panel.
(5) Install the cap-seal on the toggle switch (see Figure 21).
REV
A
JUN
1980
17

1502/1503 SEALING
NO. 3144
SEALANT
WASHER OR LUG
Figure. 22. Application of sealant to the GAIN or the 0-dB SET control bushing.
STEP 22. Install the VAR control and either the GAIN (1502) or 0-dB SET
(1503) control (see Figures 22 and 23).
A. RESISTOR, VARIABLE
(1) 1502 TPN 311-0091-00, MPL Item 2-16 (VAR control); 1502 TPN 311-
0160-00, MPL Item 2-33 (GAIN control).
(2) 1503 TPN 311-0091-00, MPL Item 2-19 (VAR control); 1503 TPN 311-
0160-00, MPL Item 2-35 (0-dB SET control).
B. Procedure.
(1) Partially unscrew Hex spacer nut and form a bead of No. 3144 sealant
around the busing threads as shown in Figure 22.
(2) Re-tignten the Hex spacer nut.
(3) Pack the Shaft/Threaded Bushing interface with G-661 lubricant as
shown in Figure 23.
(4) Form a bead of No. 3144 sealant on the end of the Hex spacer nut as
shown in Figure 23.
(5) Install the resistor in the Front Panel.
NO. 3144
SEALANT
G-661
LUBRICANT
Figure. 23. Detail showing lubrication and sealing for the variable resistor.
18