Keithley 2700, Service Manual

Page: 9 / 174

4 Troubleshooting
Introduction ................................................................................ 4-2
Repair considerations ................................................................. 4-2
Power-on self-test ....................................................................... 4-2
Front panel tests ......................................................................... 4-3
KEY test .............................................................................. 4-3
DISP test ............................................................................. 4-3
Principles of operation ............................................................... 4-4
Power supply ....................................................................... 4-4
Display board ...................................................................... 4-6
Digital circuitry ................................................................... 4-7
Analog circuitry .................................................................. 4-8
Troubleshooting ....................................................................... 4-11
Display board checks ........................................................ 4-11
Power supply checks ......................................................... 4-11
Digital circuitry checks ..................................................... 4-12
Analog signal switching states .......................................... 4-13
No comm link error .................................................................. 4-18
5 Disassembly
Introduction ................................................................................ 5-2
Handling and cleaning ............................................................... 5-2
Handling PC boards ............................................................ 5-2
Solder repairs ...................................................................... 5-2
Static sensitive devices ........................................................ 5-3
Assembly drawings .................................................................... 5-3
Disassembly procedures ............................................................. 5-4
Case cover removal ............................................................. 5-4
Motherboard removal .......................................................... 5-4
Card cage removal .............................................................. 5-5
Front panel disassembly ...................................................... 5-6
Removing power components ............................................. 5-6
Instrument reassembly ............................................................... 5-7
Input terminal wire connections .......................................... 5-7
Power module wire connections ......................................... 5-7
6 Replaceable Parts
Introduction ................................................................................ 6-2
Parts lists .................................................................................... 6-2
Ordering information ................................................................. 6-2
Factory service ........................................................................... 6-2
Component layouts .................................................................... 6-2