Keithley 2002

Troubleshooting
2-57
Test 304.2 — 2MΩ open-circuit ohms
Type
Pass/Fail
Fault message 2M open circuit ohms
Description This test uses the same setup as test 304.1 except that U232 pin 10 to 11 connects the ohms ref-
erence feedback to U233 pin 3. R276 is used as a voltage divider, but R276 is not an integral part
of this test. Q214 is off, and the ohms current flows through CR214 to LO.
Drawing reference Analog Board; 2002-100
Components U219, U220, U223, U233, U254, U255, and associated components.
Bit patterns
Bit pattern* Register
—U400—
01111011
—U811—
00001101
—U224—
00010111
—U432—
10000000
—U810—
00000011
—U206—
01100000
—U203—
11110100
—U411—
11111011
—U809—
11100111
—U207—
00001111
—U221—
01111011
—U406—
00000100
AD_STB
MUX_STB
R1_STB
R2_STB
*Bits associated with register IC terminals as follows:
QQQQQQQQ
87654321 87654321 87654321 87654321
IC pins: Q8=11, Q7=12, Q6=13, Q5=14, Q4=7, Q3=6, Q2=5, Q1=4.