Keithley 2700

Troubleshooting 4-17
Figure 4-3 provides a block diagram of the analog circuitry. Table 4-17 shows where the var-
ious switching devices are located in the block diagram.
Table 4-15
Ω2 signal multiplexing and gain
Range
Signal
(U163)
U129
pin 1
U129
pin 8
U129
pin 9
Gain
(U166)
100Ω
1kΩ
10kΩ
100kΩ
1MΩ
10MΩ
100MΩ
S4
S4
S4
S4
S4
S4
S4
OFF
OFF
OFF
OFF
ON
ON
ON
OFF
ON
ON
ON
OFF
OFF
OFF
ON
OFF
OFF
OFF
OFF
OFF
OFF
×100
×10
×10
×10
×1
×1
×1
Table 4-16
Ω4 signal multiplexing and gain
Range
Signal
(U163)
U129
pin 1
U129
pin 8
U129
pin 9
Gain
(U166)
100Ω
1kΩ
10kΩ
100kΩ
1MΩ
10MΩ
100MΩ
S4 then S7
S4 then S7
S4 then S7
S4 then S7
S4 then S7
S4 then S7
S4 then S7
OFF
OFF
OFF
OFF
ON
ON
ON
OFF
ON
ON
ON
OFF
OFF
OFF
ON
OFF
OFF
OFF
OFF
OFF
OFF
×100
×10
×10
×10
×1
×1
×1
Table 4-17
Switching device locations
Switching devices Analog circuit section (see Figure 4-3)
Q101, Q102
Q114, Q136, Q109
K101, Q113, Q105, Q104, Q108
Q121
K102, U103, U105, U111
U133, Q120, Q123, Q124, Q125, Q126
K103
U129, U163
SSP (Solid State Protection)
DCV Divider
DCV and Ohms Switching
Sense LO
AC switching and Gain
Ohms I-Source
Current Shunts
A/D Mux and Gain