HP 437B - MULTIPLE ERROR CODES AND TROUBLESHOOTING SUGGESTIONS

HP 437B
Service Sheet BDI
113 The following table lists troubleshooting suggestions for patterns of multiple
Note | displayed error codes. To find the right troubleshooting suggestion, locate
the error code pattern that is in the exact sequence displayed on the Power
Meter’s front panel.
Some combinations of error codes may occur which are not in this table. To
help identify the cause of the problem, locate common data and control lines
among the components indicated by the error codes.
Table 8-6. Multiple Error Codes and Troubleshooting Suggestions
Troubleshooting Suggestions
65, 67 Verify TTL signals at A3U24 pins 21, 23, and 36. If TTL
signals are present, replace A3U24.
65, 75, 67
65, 71, 68, 75, 67
Verify TTL signals at A3U24 pin 35. If TTL signals are present,
replace A3U24.
Verify TTL signals at A3U12 pin 11. If TTL signals
are present, replace A3U 12.
65, 70, 68, 69, 75, 67 Verify TTL signals at A3U20 pin 5. If TTL signals
are present, replace A3U20.
Verify TTL signals at A3U25 pin 23. If TTL signals are present,
replace A3U25.
66, 68, 69, 75, 67 Verify TTL signals at A3U20 pin 7. If TTL signals
are present, replace A3U20.
Verify TTL signals at A3U20 pin 3 and A3U12 pin 15.
If TTL signals are present, replace A3U 12.
66, 65, 70, 68, 75, 67
Verify TTL signals at A3U20 pin 5. If TTL signals are
present, replace A3U20.
66, 65, 70, 75, 67
SERVICE §8-27