346B User Manual Publication No. 980956 Rev. A
Trouble Shooting 5-2
Astronics Test Systems
Save & Recall
Problem:
Cannot save or recall any file.
1. Check
Chapter 2,
Operation and make sure the procedure is followed
correctly.
2. All the memory for file is filled up and there is no more room for any more files.
Read to the SAVE/FILE in
Chapter 2,
Operation.
3. The SRAM could be bad. Replace U8 on the main board. Once the new
SRAM is installed, you have to delete all the files in the SRAM and program
the new files. (Refer to the SAVE/FILE in
Chapter 2,
Operation).
Frequency
Problem: The unit reads a different frequency than is entered.
1. Make sure the ENTER key has been pressed; each of the 6 digits should
have a number in it.
2. The problem could be with any of the 5 counters marked U21-U25. Replace
one at a time to fix the problem.
3. The problem could also be caused by the I/0 ports. Replace the ports Ul7-
U20 one at a time to fix the problem.
Level
Problem: There is no output at the BNC connector.
1. Could be a problem with the +18 or -18 Volts on the power supply. Check the
regulators for proper voltages.
2. The output driver circuit could have been damaged, if there is a signal at pin 8
of U46 and no signal at pin 11 of U43 (any one of the transistor Q1-Q4 could
be bad).
Problem: The output level is not correct
1. Make sure the ENTER key has been pressed and each of the 4 digits should
have a number in it.
2. The unit may require calibration (Refer to
Chapter 4
, Calibration).
3. The D/A Converter could be bad. Replace U47 on the main board.
