Troubleshooting
2-81
Bit patterns
Test 406.3 — Read sample and hold for test 406.6 comparison
Type
Circuit Exercise
Fault message
None
Description
This test is the same as test 406.2 except that the value is stored for use in comparison calculation
in test phase 406.6.
Drawing reference
Analog Board; 2002-100
Bit patterns
Test 406.4 — Read DAC V for sample and hold test 406.6
Type
Circuit Exercise
Fault message
None
Description
DAC U433 and op amp pair U430 are set up to generate -0.01 VDC at and tied to
ACF through R491 and U412. ACF is tied to pin 7 of multiplexer U414. The output of the mul-
tiplexer is tied to the A/D through buffer U403, ACV/A input to U222, and the A/D buffer in X1
gain configuration. The value of the DAC voltage is measured and stored. This value will also
be applied to the circuit in tests 406.5 and 406.6. In this manner, the applied value to the circuit
Bit pattern*
Register
—U400—
01011101
—U811—
00001101
—U224—
00010111
—U432—
01100100
—U810—
00000011
—U206—
01110000
—U203—
10001110
—U411—
11111011
—U809—
11100111
—U207—
11001111
—U221—
11101001
—U406—
01001101
AD_STB
MUX_STB
R1_STB
R2_STB
*Bits associated with register IC terminals as follows:
Q
Q
Q
Q
Q
Q
Q
Q
87654321
87654321
87654321
87654321
IC pins: Q8=11, Q7=12, Q6=13, Q5=14, Q4=7, Q3=6, Q2=5, Q1=4.
Bit pattern*
Register
—U400—
01011101
—U811—
00001101
—U224—
00010111
—U432—
01100100
—U810—
00000011
—U206—
01110000
—U203—
10001110
—U411—
11111011
—U809—
11100111
—U207—
11001111
—U221—
11101001
—U406—
01001101
AD_STB
MUX_STB
R1_STB
R2_STB
*Bits associated with register IC terminals as follows:
Q
Q
Q
Q
Q
Q
Q
Q
87654321
87654321
87654321
87654321
IC pins: Q8=11, Q7=12, Q6=13, Q5=14, Q4=7, Q3=6, Q2=5, Q1=4.
