Test 601.1 — AMP SHUNT
Bank AMP/OHM
Inputs INPUT HI to AMPS short
Expected Value <none specified>
Limits <none specified>
Fault Message <none>
Description This test requires an external jumper wire be installed from the INPUT HI
jack to the AMPS jack on the front panel. There is a routine in software that
generates a test signal current for the ACV AMP test. This signal generation
is described in test 601.2.
The test signal is routed through the front end circuit to the front panel IN-
PUT HI jack. The jumper connects the test signal to the front panel AMPS
jack. The test signal is routed through K103 (pins 3 and 8 to pins 4 and 7. The
signal current then flows through the series combination of R205 (10Ω) and
R158 (0.1Ω) to ground. This generates an AC voltage that is connected to
AMPSHNT through S101 and R142.
The ACV front end is set up for the non-inverting configuration as follows:
K102: /SETK1 low, /RESETK1 high
U103: Pins 8 and 9 low
U105: Pin 9 high
The AMPSHNT signal is routed through U105 (pin 16 low) to the plus in-
put of U112 which is configured for ×10 gain. The output signal of the op
amp is routed through U105 (pin 1 low) and coupled across C115 to U118
which is configured for ×2 gain.
The output of U118 goes to U110 the TRMS converter through R129 and
the parallel C113 and C114. U110 OUT pin 11 is feed through its own inter-
nal buffer pin 1 to 16 and the signal out is AC_MED. AC_MED signal is se-
lected at U163 pin 6 to 8 and fed to A/D buffer U166 through Q117. The A/
D buffer is set up for ×1 gain through U129 pin 3 to 2 with /×1 low. This test
is the setup phase for the next test phase.
2-56 Troubleshooting
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