Keithley 2002 Repair Manual page 124

Test 600.2 — Ohms sense LO
Type
Fault message
Description
Drawing reference
Components
Bit patterns
Pass/Fail
Ohms sense LO
A 4-wire short on the input lines applies LO through the SENSE_LO path of R360, U242 pins
15 to 14, to the ADGND MUX U253, then to the A/D MUX at U226. Common is routed through
U222 S1 to U226 pin 3. A/D MUX gain is X1.
NOTE: The INPUTS and SENSE jacks must be externally shorted together to run this test.
Analog Board; 2002-100
R360, U242, and associated components.
—U811—
00001101
—U224—
00010111
—U400— —U432—
01111011 10000000
*Bits associated with register IC terminals as follows:
Q Q Q Q
87654321 87654321
IC pins: Q8=11, Q7=12, Q6=13, Q5=14, Q4=7, Q3=6, Q2=5, Q1=4.
Bit pattern*
—U810—
00000011
—U206—
01110000
—U203—
10001110
—U411—
11111011
Q Q Q Q
87654321 87654321
Troubleshooting
Register
—U809— AD_STB
11100111
—U207— MUX_STB
11111101
—U221— R1_STB
11101001
—U406— R2_STB
00000100
2-111