Dsp Board Removal - Keithley 2015 Service Manual

3. Disconnect the front and rear input terminals.
You must disconnect these input terminal connections for both the front and rear inputs:
• INPUT HI and LO
• SENSE HI and LO
• AMPS
Remove all the connections except the front AMPS connection by pulling the wires off
the pin connectors. To remove the front panel AMPS input wire (white), first remove the
AMPS fuse holder, then use needle-nose pliers to grasp the AMPS wire near fuse hous-
ing. Push the wire forward and down to snap the spring out of the fuse housing. Carefully
pull the spring and contact tip out of the housing.
4. Unplug cables:
• Unplug the display board ribbon cable from connector J1014.
• Unplug the transformer cables from connectors J1016 and J1015.
• Unplug the OPTION SLOT ribbon cable from connector J1017.
5. Remove the fastening screw that secures the DMM board to the chassis. One of these
screws is located along the left side of the unit towards the rear, and it also secures U114.
The other screw is located at the right front of the chassis near the front/rear switch,
S101.
During re-assembly, replace the board, and start the IEEE-488 and RS-232 connector
nuts and the mounting screw. Tighten all the fasteners once they are all in place and the
board is correctly aligned.
6. Remove the DMM board, which is held in place by edge guides on each side, by sliding
it forward until the board edges clear the guides. Carefully pull the DMM board from the
chassis.

DSP board removal

Perform the following steps to remove the DSP (136) board. This procedure assumes that the
case cover and the DMM board have been removed.
1. Remove the nuts from the two BNC jacks on the rear panel.
2. Unplug cables:
• Unplug the power entry module cable, J1021.
• Unplug the transformer primary connections, J1018 and J1019.
• Unplug the transformer cable from J1020.
• Unplug the DMM board connectors, J1022, J1024, and J1026.
• Unplug the transformer cable, J1031.
3. Remove all seven screws that secure the DSP board to the chassis.
4. Slide the board toward the front of the chassis until the BNC jacks have cleared the chas-
sis and the board is clear of the guide pins, then remove the board.
During re-assembly, replace the board by lining up the guide pins over the slots, then
slide the board toward the rear. Loosely install all screws, then install and tighten the
BNC jack nuts. Tighten all screws.
Disassembly 5-7