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Model 8904A | Service |
TROUBLESHOOTING
GENERAL
The goal of the following troubleshooting procedures is to isolate the fault to a single, replaceable assembly. The instrument assemblies are as follows:
0A1 Keyboard
0A2 Digital
0A3 Output
0A4 Power Supply
0A5 Display
0A6 High Power Output (Installed only in Option 006)
0A10 Output (Installed only in Option 002)
The exploded drawings at the end of section 6 in the manual will assist in locating, disassembling, and reassembling these assemblies.
The troubleshooting procedures assume the failure is catastrophic. For subtle or
To isolate the fault to a printed circuit board assembly,it is usually necessary to check only the signals on the interface (interconnections) between assemblies. Specifically, this will be the interface between the A2 Digital Assembly and one of the other assemblies. The A3 (or A10) Output Assembly can be troubleshot to the component level using the troubleshooting information on the schematic diagrams.
NOTE
If the A 2 Digital Assembly is replaced, it will be necessary to restore the instrument’s serial number and, where applicable, Option 001 andfor 003 in
The the troubleshooting procedures verify the signals in the:
0A2 Digital Assembly to A3 (or A10) Output Assembly Interface
0A2 Digital Assembly to A1 Keyboard Assembly Interface
0A2 Digital Assembly to A5 Display Assembly Interface
0A3 or A10 Output Assembly
0A6 High Power Output
Other procedures include:
How to Restore the Serial Number in a Replacement A2 Digital Assembly
0How to Restore Options 001 and 003 in a Replacement A2 Digital Assembly
0How to Replace the Memory Backup Battery
NOTE
If the instrument has Option 002, a second output, and the fault appears only on one output, swap the A3 and A10 assemblies and see if the fault tracks the output assembly. If it does, then the Output Assembly is at fault; otherwise, the A2 Digital Assembly (or possibly an interconnection) is at fault.
rev.15DEC89 | Troubleshooting (General) |