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Troubleshooting

2-74

Test 404.4 — Absolute value X1 gain, +half-scale DAC

Type

Pass/Fail

Fault message Absolute value gain = 1

Description DAC U433 and op amp pair U430 are set up to generate +2.33 VDC at PRECOMP+. This signal

follows the same path as test 404.3.

Drawing reference Analog Board; 2002-100

Components U403, U414, U417, U419, U428, U430, U433, and associated components.

Bit patterns

Test 404.5 — Absolute value X1 gain, +full-scale DAC

Type

Pass/Fail

Fault message Absolute value gain = 1

Description DAC U433 and op amp pair U430 are set up to generate +4.48 VDC at PRECOMP+. This signal

follows the same path as test 404.3.

Drawing reference Analog Board; 2002-100

Components U403, U414, U417, U419, U428, U430, U433, and associated components.

Bit patterns

Bit pattern* Register

—U400—

01011100

—U811—

00001101

—U224—

00010111

—U432—

10111000

—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:

QQQQQQQQ

87654321 87654321 87654321 87654321

IC pins: Q8=11, Q7=12, Q6=13, Q5=14, Q4=7, Q3=6, Q2=5, Q1=4.