National 147 problem

[cdman]

I have a National 147 that is giving me problems. I arrived at the location and the bill validator wasn't working, It would pull in the bill and hold it. It would give you the credit but would not vend? (also it would not stack the bill "which is normal until it vends") If you cycle power the dollar bill would come back out. Also if you used coins the machine works fine, even giving correct change. After swapping the Mars validator the problem was still there. I called National GPL and was told that it is probably the PCB Assembly Coin Mech & Validator Interface board. After the phone call i removed the board and did a visual inspection. When i reinstalled the board the machine and validator started working correctly. At this point I assumed a bad connection, i powered down the machine and removed and wiggled all the wires in that area. When I powered back up I got the three beeps, display read SERVICE, error on all trays (motors), validator locked out (two flash code). To fix it I had to do an audit clear (which i was told by National GPL would not clear the ram and had nothing to do with my symptoms). At this point I was back to the original problem- machine works fine but only with coins! After moving the wires / plugs and getting the errors again, I cleared the audits a second time and the machine started working properly, now I don't know where I stand?

ANY INPUT THANKS

[cdman]

Wow no one has had a similar problem? 

[canuck]

I haven't..sorry I can't help.

[mxer518]

I feel your pain, for me it was the harness which i figured would be the last thing that was wrong with it. what worked for me was to remove the harnesses one by one and inspect them and check for loose pins (there were several) and put electrical grease on the connectors and plug them back in. from that point until now i have not had any further problems.