As what Taylor has said there they can be some cash hiden with in these.
Gettting back to the fault once again as Taylor has said unplug and reconnect looms
Do check all fuses
Do check all brass contacts , Depending on the fault cleaning these with brasso (HOW EVER PLEASE MAKE SURE POWER IS OFF AS THESE DID/DO HAVE 240V RUNNING LIVE ON TO THESE POINTS) Can fix these. A good can of air duster also helps to go over the relays.
Do check that there is no jammed coins on any relay points and one that i can remember is to check on the reels also seen it a number of time where coins had been welded onto the reel contact panel
These can stop the machine from even starting as there is a short across the points
Also check the relays that look burnt. Most where in a clear plastic case, even try and remove these and resit them even a little tap while its out.
.._-=It`s not a problem only a challenge =-_..