A3 Controller/Reference Board Troubleshooting; Standard Troubleshooting Procedures - HP 5501B Operating And Service Manual

8-133. A3 CONTROLLER/REFERENCE BOARD TROUBLESHOOTING

8-134. Service for A3 is divided into the following procedures, consult paragraph 8-64, HP5501B
Trouble Isolation to determine which procedure to use.
a. Digital
b. Photodiode and Amplifier
c. Liquid Crystal
d. Subtracting Sample and Hold
e. Power Amplifier
f. Warmup Error Amplifier
g. Power Supplies
h. Reference Receiver

8-135. Standard Troubleshooting Procedures

8-136. In the following tests, reference is frequently made to "localize the defective element by standard
troubleshooting procedures". This consists of the following:
a. The test procedure places a group of IC's in a definite state and:
b. When the test procedure specifies a suspected component, replace it and run the test
again.
c. When signal characteristics are known, measure the signals until a component is found
that has correct inputs but erroneous outputs. Most likely this component is defective. If
not, check for:
1. output loading such as a board short
2. shorted input on a downstream circuit
If inputs are incorrect, check for open traces and faulty outputs from previous stages.
d. If an erroneous signal comes from another board, perform the test procedure for the
suspected board.
1. Provides the correct values of the input and output signals characteristics
2. Implies use of the schematic to determine the signal characteristics
3. Simply states a suspected component
OR
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HP5501B
Service
8-37