kennybobby
(kennybobby)
10
It appears to be a thermal issue and not a defective component. If the board is potted with epoxy then troubleshooting will be difficult until the epoxy is removed. Epoxy has a high thermal coeff of expansion, it moves and grows quite a bit due to temperature change.
There is likely a bad solder joint that is being pulled by the expansion of the epoxy which is causing the circuit to open.
If it works for brief periods to scan currency then it may still be useful to you; if you need a longer duty cycle and the cutoff is not acceptable, then it will need to be repaired or replaced.
Who does repairs? seems to be plenty of smart guys on this forum.