Keithley 2701, Service Manual

Page: 100 / 168

5-4 Disassembly Model 2701 Service Manual
Disassembly procedures
Case cover removal
Follow the steps below to remove the case cover to gain access to internal parts.
WARNING Before removing the case cover, disconnect the line cord and any test leads
from the instrument.
1. Remove Handle — The handle serves as an adjustable tilt-bail. Adjust its position by
gently pulling it away from the sides of the instrument case and swinging it up or down.
To remove the handle, swing the handle below the bottom surface of the case and back
until the orientation arrows on the handles line up with the orientation arrows on the
mounting ears. With the arrows lined up, pull the ends of the handle away from the
case.
2. Remove Mounting Ears — Remove the screw that secures each mounting ear. Pull
down and out on each mounting ear.
NOTE When re-installing the mounting ears, make sure to mount the right ear to the right
side of the chassis and the left ear to the left side of the chassis. Each ear is marked
“RIGHT” or “LEFT” on its inside surface.
3. Remove Rear Bezel — To remove the rear bezel, loosen the two captive screws that
secure the rear bezel to the chassis. Pull the bezel away from the case.
4. Removing Bottom Screws — Remove the four bottom screws that secure the case to the
chassis.
5. Remove Cover — To remove the case, grasp the front bezel of the instrument and care-
fully slide the chassis forward. Slide the chassis out of the metal case.
Motherboard removal
Perform the following steps to remove the motherboard. This procedure assumes that the
case cover is already removed.
1. Remove the RS-232 and Digital I/O fasteners.
The RS-232 and Digital I/O connectors each have two nuts that secure the connectors to
the rear panel. Remove these nuts.
2. Remove the front/rear inputs switch rod.
At the switch, place the edge of a flat-blade screwdriver in the notch on the pushrod.
Gently twist the screwdriver while pulling the rod from the shaft.
3. Disconnect the front input terminals.
You must disconnect these input terminal connections:
• INPUT HI and LO
• SENSE HI and LO
• AMPS