Keithley 2750 - Page 99

Model 2750 Multimeter/Switch System Service Manual Troubleshooting 4-13
Troubleshooting
Figure 4-4
Simplified schematic of dry circuit ohms
+
-
+
-
SSP*
SSP*
SSP*
SSP*
DUT
INPUT
LO
INPUT
HI
SENSE
HI
SENSE
LO
Mux
*SSP: Solid State Protection Circuit
↔
ON
I Source
10μA
100μA
1mA
10mA
A/D
Converter
Gain
Amp
1MΩ
ON
ON
0.8μF
20mV Reference
(Main Clamp,
Monitors SENSE HI)
50mV Reference
(Secondary Clamp,
Monitors INPUT HI)
100kΩ