Keithley 2520, Service Manual, Page: 95 / 137

Model 2520 Pulsed Laser Diode Test System Service Manual Disassembly 5-5
3. Unplug cables:
• Unplug the ribbon cables from J1007 and J1033.
• Unplug the cable going to the power supply module from J1011.
• Unplug the cable going to the OUTPUT indicator from J1034.
• Unplug the wires going to the rear panel PULSE SYNC OUT jack from
J1006.
4. Remove the motherboard. Slide the motherboard forward slightly until the rear
panel connectors clear the holes in the rear panel, then remove the board.
During re-assembly, replace the motherboard, and start the IEEE-488,
DIGITAL I/O, RS-232, and TESTHEAD CONN1 connector screws and the board
mounting screws. Tighten all the fasteners once they are all in place and the board
is correctly aligned. Be sure to plug in all cables.
Front panel disassembly
Use the following procedure to remove the display board and/or the push-button switch
pad.
1. Remove the front panel assembly. This assembly has four retaining clips that snap
onto the chassis over four pem nut studs. Two retaining clips are located on each
side of the front panel. Pull the retaining clips outward and, at the same time, pull
the front panel assembly forward until it separates from the chassis.
2. Unplug the display board ribbon cables.
3. Using a thin-bladed screwdriver, pry the plastic PC board stop (located at the bot-
tom of the display board) until the bar separates from the casing. Pull the display
board from the front panel.
4. Remove the switch pad by pulling it from the front panel.