Troubleshooting; Ω2/Ω4 Reference Switching; Dca Signal Switching; Aca Signal Switching - Keithley 2000 Repair Manual

Table 2-9
Ω 2/ Ω 4 reference switching
U133 U133
Range
/.7V /7V
100Ω OFF ON
1kΩ OFF ON
10kΩ OFF ON
100kΩ ON OFF
1MΩ ON OFF
10MΩ OFF ON
100MΩ OFF ON
Table 2-10

DCA signal switching

Range K103
10mA ON
100mA OFF
1A OFF
3A OFF
Table 2-11

ACA signal switching

U105
Range K103
pin 16
1A OFF ON
3A OFF ON
Tables 2-12 through 2-16 can be used to trace the analog signal through the A/D multiplexer
(U163) to the final amplifier stage. These tables show the MUX lines (S3, S4, S6, S7) that are
selected for measurement during the SIGNAL phase of the multiplexing cycle. Also included
are switching states of analog switches (U129) that set up the gain for the final amplifier stage
(U166).
Q123 Q125 Q124 Q126 Q120
ON ON OFF OFF
ON ON OFF OFF
OFF OFF ON ON
OFF OFF ON ON
OFF OFF ON ON
OFF OFF ON ON
OFF OFF ON ON
U105 U111 U105
pin 1 pin 16 pin 8
ON OFF OFF
ON ON OFF

Troubleshooting

ON
ON
ON
ON
ON
OFF
OFF
U103 U103
pin 16 pin 1
OFF OFF
OFF OFF
2-15