6-67
4. If all inputs are good, replace U270.
3. Check U270 pins 1 and 2 for activity (ACD line is the data input). Repair if inactive.
2. Check U270 pin 8 for activity (GA SR ClK signal line); if inactive, repair.
1. Check U270 pin 9 for a HI level. If not +5 V, check R269 and source of the +5 V.
Run test 2540 in CONTINUOUS mode. Using the CH 2 probe:
NOTE
For the following, set the Trigger Position of the test 2430 to 3/4. If using an analog scope
for testing, use the appropriate holdoff and trigger level to view the signals of interest.
Set up the 2430 test scope as in Step 1 of the 2110 troubleshooting procedure.
Troubleshooting Procedure:
For this test, the MSB of U270 (pin 13) will be compared with what the MSB should be with each shift
of the register. If one of the bits differs from the loaded-in pattern, the test fails.
Testing Method:
Acquisition Control Register A1OU270(schematic diagram 5):2540
GATE ARRAY
4. If all inputs are good, replace U530.
3. Check U530 pins 1 and 2 for activity (ACD line is the data input). Repair if inactive.
2. Check U530 pin 8 for activity (PD SR ClK signal line); if inactive, repair.
1. Check U530 pin 9 for a HI level. If lO, then check R531 and source of +5
v.
Run test 2530 in CONTINUOUS mode. Using the CH 2 probe:
NOTE
For the following, set the Trigger POSitionof the test 2430 to 3/4. If using an analog scope
for testing, use the appropriate holdoff and trigger level to view the signals of interest.
Set up the 2430 test scope as in Step 1 of the 2110 troubleshooting procedure.
Troubleshooting Procedure:
For this test, the MSB of A10U530 (pin 13) will be compared with what the MSB should be with each
shift of the register. If one of the bits differs from the loaded-in pattern, the test fails.
Testing Method:
Acquisition Control Register A1OU530(schematic diagram 5):
2530
PEAK
DETECTOR
5. If checks good to this point and the test still fails, replace U511.
4. Check U221 pin 13 for activity; replace U221 if inactive.
3. Check U221 pins 1 and 2 for activity (ACD line is the data input). If ACD missing, troubleshoot the
signal path to and gating on the inputs of DAC Multiplexer Select register U272 (diagram 5).
Table
6-6
(cont)
Maintenance-2430 Service
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