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8-25.
Service Aids on Printed Circuit Boards
8-26.
The servicing aids include test points, tran-
sistor and integrated circuit designations, adjustment
callouts, and assembly stock numbers.
8-27.
After Service Safety Checks
8-28.
Visually inspect interior of instrument for any
signs of abnormal internally generated heat, such as
discolored printed circuit boards or components,
damaged insulation, or evidence of arcing. Deter-
mine and remedy cause of any such condition.
8-29.
Using a suitable ohmmeter, check resistance
from the front and rear panels to ground pin on power
cord plug. The reading must be less than one ohm.
Flex the power cord while making this measurement
to determine whether intermittent discontinuities
exist.
8-30.
Check resistance from the front and rear panel
BNC connector shells and neutral (tied together) with
the power switch on and the power source discon-
nected. The minimum acceptable resistance is two
megohms. Replace any component which results in a
failure .
8-31.
Check line fuse(s) to verify that a correctly
rated fuse is installed.
WARNING
TO ASSURE THE INTEGRITY OF THE SAFETY
GROUNDING CIRCUIT:
1.
Verify the star washer and rear panel BNC
connector nut are installed and securely
tightened.
2.
Verify the solder lug with green/yellow
wire (soldered to the A 1 board) is securely
fastened between potentiometer R1 and
the front panel.
8-32.
HP 5384A and HP 5385A Disassembly
Procedures
8-33.
The following procedures describe how to
disassemble the HP 5384A and HP 5385A counters.
a.
Remove the two plastic feet from the bottom
rear of the counter. The removal instructions are
molded into the bottom of each foot.
b.
Remove the dark green adhesive strips on each
side near the front of the instrument.
HP 5384A and HP 5385A
Service
c.
Remove four 6-32 screws from the bottom
cover of the instrument.
d.
Gently lift the top cover up and off the
instrument.
8-34.
If there is an interface board in the instrument,
follow the next three steps for disassembly. If there is
no interface board present, skip the following three
steps and continue with step "h".
e.
Disconnect the ribbon cable from the mother
board.
f.
Remove the two screws on the rear panel that
hold it in place.
g.
Remove the interface board from the instru-
ment by pressing in the plastic catch near the top of
the support post and lifting up on the board.
h.
Remove two 6-32 screws that hold the mother-
board to the bottom cover. Gently lift the mother-
board from the bottom cover. The front and rear
panels will remain attached to the motherboard.
8-35. Assembly Identification
8-36.
The name, assembly number, and Hewlett-
Packard part number of the HP 5384A and HP 5385A
assemblies are listed in Table 8-1.
·
Table 8-1. Assembly
Usage
REF.
PART NAME
HP PART
DES.
NUMBER
A1
Main Board Assembly
05384-60001
A1
Main Board Assembly,
TXCO (Opt. 001)
05384-60006
A1
Main Board Assembly,
Oven Osc. (Opt. 004)
05384-60007
A1
Main Board Assembly,
05385-60001
(TCXO Std)
A1
Main Board Assembly,
Oven Osc. (Opt. 004)
05385-60003
A2
Display Assembly
Keyboard Assembly
05384-60102
Liquid Crystal Display
Assembly
05384-60104
A3
Battery Pack Assembly
05384-60003
A4
HP-IL Board Assembly
05006-60004
AS
HP-IB Board Assembly
05384-60005
8-3
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Troubleshooting
