Bally 5000+ will not accept coins.. Comparator?

[aballworth]

Bally 500+ Fire and Ice. The power supply was dead so I replaced with a different supply. The machine powers up fine and works when I hold the rake out on the comparator, it will accept coins and makes coin in sound.  The "Insert Coin" light does not come on. The reels will spin and hopper pays out like it is working just cannot get the comparator to accept coins. When I power it up, The rake does engage for a second then drops out, so I believe it is working. Also will throw an error if I insert more than two coins or try to insert coin backwards as if I was stringing it. Does anyone have any advice? Also, Could someone explain door optics on this machine? Is it just the switch at the bottom or is there something else?
               

[retroelectro]

I had the same. Reason is that CPU keeps the inhibit signal to comparator high (and the light off). Funny thing is that if you manage to fool comparator somehow, CPU still accepts the coins.. RAM clear fixed it for me though.

According to docs there's cam switch on the door and hinge switch at the bottom. However in my model there's no cam switch at all, just wires going to the hinge switch which is handling both signals.

[aballworth]

Ok thank you.. Just curious which ram clear you had to use? I cannot get it to work.

[retroelectro]

My game is from 1991 so none of the methods worked for me either. After changing main ROMs to older ones, I can clear the RAM with the method where you short pins on the door distribution board.