Keithley 2520, Service Manual, Page: 97 / 137

Model 2520 Pulsed Laser Diode Test System Service Manual Disassembly 5-7
Testhead disassembly
Follow the procedures below in the following order to disassemble the testhead.
Case disassembly
1. Remove the eight screws that secure the case top to the case bottom.
2. Remove the nuts and washers that secure the four BNC PULSED and two triax
DETECTOR jacks to the front panel.
3. Slide the case top forward until it clears the BNC and triax jacks, then continue
sliding the case top forward away from the case bottom.
Output board removal
1. Remove the two screws that secure the REMOTE INTERLOCK connector to the
rear panel.
2. Remove the nut that secures the KEY INTERLOCK to the rear panel.
3. Unplug the ribbon cable from J4.
4. Remove the three screws that secure the output board to the standoffs.
5. Pull the output board forward until the KEY INTERLOCK and REMOTE INTER-
LOCK connector clear the rear panel, then remove the output board.
Input board removal
1. Remove the two screws that secure the MAINFRAME CONN 1 connector to the
front panel.
2. Unplug the MAINFRAME CONN 2 ribbon cables from the input board.
3. Unplug the INTERLOCK STATUS and POWER ON indicator light cables from
J5 and J6.
4. Remove the screws and standoffs that secure the input board to the case bottom.
5. Pull the input board forward until the MAINFRAME CONN 1 connector clears the
rear panel, then carefully remove the input board from the case bottom.
Testhead re-assembly
Re-assemble the testhead by reversing the above procedure. Be sure that all cables are
connected, and that all screws, standoffs, and nuts are installed and properly secured.