Can't say I know what your issue is but I have 12 in service. * have been in service since I tool over the location 20+ years ago and the other 4 I added to Vacs a few years ago. So far I can't recall one failing. Since I am just outside Chicago the environment is brutal.
Sorry if I'm getting in the middle here but......
1) does timer read FAIL
2) is it the same bay
3) is time just flashing or LED readout look scrambled
4) does it fail when customer selects that one selection
I would check wiring and voltage.
Before taking out timer test with different
coin acceptor
I have a bay farthest from the equipment room that timer was messing up. I started by unplugging the heater and problem went away. Few months later I replaced the heater everything working.
When on, example, wash does it fail
Could be bad coil