S+ Some days coins are accepted, some days they are not. Can you figure why ?

[gordy]

Have more info so thought it best to start over. For a year these symptoms have come and gone, then recur:
  One coin will be accepted, then others go to the tray. Re-plug the connection to the comparitor and all 3 coins are accepted for one to 40 plays and then one or two coins will be accepted  Another day it will be OK for the whole day. The next day only one coin is accepted but no more until the re-plugging or rotating the sample coin slightly. then it works for a couple minutes.  Then, only one out of 7 comparitors worked once in a while and after a while only when the gate on that one comparitor was wedged open so all coins go to the hopper. This also only worked for indefinite times.
    TRIED       7 known good comparitors, a known good CPU [ game board ] from a similar machine,  the comparitor bracket and coin optics and harness from a similar machine,  plugged and unplugged the harness from the power supply to the mother board and changed this harness,  Checked the door optics and they reset the machine perfectly every time.
    Yesterday all 7 comparitors worked and the machine played perfectly over 100 times. Cant predict what will happen today.  Afraid to sell it.  Any brilliant ideas ?  Thank you.

[cowboygames]

I'd be for looking at the wiring harness back to the MPU. You may have a wire that's cracked internally where they cross from the door to the cabinet. Opening and closing the door bends them and over a period of time they can crack and break

[4 Deuces]

I used to have this problem and discovered I put the coin in the comparitor incorrectly.  I was putting the coin all the way in the back up against the copper dial when I should have just simply placed the coin in front allowing only the force of the spring-loaded latch to hold it in place.  Any chance you have the coin all the way in the back like I did?

[knagl]

Have you ever tried adjusting the sensitivity adjustment on the comparators to make them less likely to reject coins?

[gordy]

4Deuces: Yes, for many years the coin has been put in correctly. That's why the other comparitors worked perfectly in other machines.
knagl : Yes, always have set them to not reject for home use.
cowboy: I better check that harness.  Think I did when I re-seated where the harness goes to the CPU, but will take a better look.  Just 3 days ago on another  "S+ " there was a pinched wire at the door that was so tiny that it escaped notice twice.
   Thanks all.  Gordy

[paul]

Gordy Knaql has a good sugestion put a small screw driver in hole on compairitor and turn it all the way counter clock wise do not force this will take it to the less rejection position     Paul

[jay]

I use tokens in mine and it occasionally (6 - 8 mths) goes brain dead and forgets to accept coins.

I have tried adjusting sensitivty, reseating the coin, swapping comparitors between machines etc and replacing the token with another seems to be the only thing to do the trick.
I am not sure if the token (being of questionable metalergic properties) becomes magnitized or what but swapping the token out with another works for me.

[gordy]

I tried 7 known good comparitors with 7 different quarters and got the same responses.  When the machine worked partially, sometimes all  7  worked partially.  When only one of them worked, the others did not work at all.  When only one of them worked by jamming the gate open , the rest did not work at all. When I needed to get the one good one working I could do it by doing one of 3 things : 1. change the quarter, 2. rotate the quarter 3. unplug and plug the harness to the comparitor.