Front Panel Disassembly - Keithley 2002 Repair Manual

Disassembly
A. Disconnect the transformer ground. A kep nut is
used to connect this green ground wire to a threaded
stud on the chassis.
B. Unplug the transformer. There are three plugs for
the transformer. Two are located on the analog board
at connectors J1024 and J1025, and the third is lo-
cated on the digital board at connector J1032. Turn
the chassis upside-down to gain access to the plug
on the digital board. When finished, return the chas-
sis to the up-right position.
C. The transformer is secured to the side of the chassis
by a single screw. Remove this screw, and pull the
transformer out of the chassis.
4. Remove AC Power Receptacle: Remove the AC power
receptacle as follows:
A. Disconnect the receptacle ground wire. A kep nut is
used to connect this green ground wire to a threaded
stud on the chassis.
B. Unplug the AC power receptacle cable. The connec-
tor for this cable is located on the analog board next
to the power receptacle.
C. A spring clip on each side of the receptacle is used
to secure it to the rear panel of the chassis. To re-
move it, press both clips inward and, at the same
time, push the receptacle out of the access hole in
the rear panel of the chassis.
5. Unplug Cable to Digital Board: On the left side of the
analog board there is a ribbon cable going to the digital
board. Turn the chassis upside-down, and unplug this
cable at connector J1027 on the digital board. Return the
chassis to the right-side-up position.
6. Disconnect Input Terminals: There are 10 input termi-
nal connections (five for the front and five for the rear).
Nine of these terminal wires are disconnected by simply
pulling them off the pin connector on the input termi-
nals. The front panel AMPS terminal wire must be un-
soldered from the analog board. The solder connection
for this white/blue wire is located next to the INPUTS
switch.
Terminal wire color identification for re-assembly is as fol-
lows:
Terminal Front Rear
INPUT HI Red White/Red
INPUT LO Black White/Black
SENSE HI Yellow White/Yellow
SENSE LO Grey White/Grey
AMPS White White/Blue
7. Remove Regulator Clip: A metal clip is used to transfer
heat from two power supply devices (R101 and Q528)
3-4
to the chassis. The clip is located on the left side of the
chassis towards the rear. The clip is removed by pulling
it upward. You may need to use a small flat-bladed
screwdriver to pry it up.
CAUTION
The regulator clip allows the chassis to
serve as a heat sink for R101 and Q528.
To prevent damage to these devices (due
to overheating), be sure to install the clip
when re-assembling the Model 2002.
8. Unfasten Analog Board: The analog board is secured
to the chassis at the rear panel by the two BNC connec-
tors (External Trigger and Meter Complete). At the rear
panel, remove the nuts and lock washers for the BNC
connectors. Also remove the chokes.
9. Remove Analog Board: The board is held in place by
edge guides on each side of the chassis. Slide the analog
board forward until the board edges clear the guides, and
then carefully lift the board out of the chassis. The bot-
tom shield on the analog board can be removed by sim-
ply pulling it off the board.
With the analog board removed, the cool-
ing fan can be removed as explained in
paragraph 3.7.
3.6

Front panel disassembly

Use the following disassembly procedure to remove the dis-
play board and/or the pushbutton switch pad. Drawing 2002-
052 shows how the front panel separates from the chassis,
and drawing 2002-040 shows an exploded view of the front
panel assembly.
Before performing the following proce-
dure to remove and disassemble the front
panel, remove the case cover as explained
in paragraph 3.4.1.
Perform the following steps to remove and disassemble the
front panel:
1. Unplug Display Cable: Turn the chassis upside-down,
and unplug the display cable from the digital board at
connector J1033.
NOTE
NOTE