Before removing the processor board, check the following areas:
- Verify the problem by checking the input test in the self test mode
- Check to see if the button assembly is clean and has no broken or missing parts
- If there is a faulty microswitch, replace it
- If hold switch 5 is nonfunctional, replace hold switch 4 first
- If the microswitch is wired incorrectly, reconnect by checking another machine of the same type
- Connect one meter lead to the normally open leg of the switch and connect the other meter lead to the chassis ground (B gnd), then measure for 8 to 10 VDC
- Activate the switch – the voltage should drop to zero volts
- If voltage is missing, use this diagram to test for wire continuity
If that doesn’t work, try the following steps:
- Replace the processor board with a “known good” one
- If the processor board seems bad, check eBay for replacement or repair service
- If the processor board is good, then replace the motherboard
- To repair the motherboard, use this diagram to isolate the bad trace
- If the motherboard and processor board are good, then use this diagram to test for wire continuity
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