My Williams Skylab started to blow the 24 volt fuse (15 amps). I, at first, thought the problem was a shorted score motor coil because the fuse wouldn't blow when I removed the power from the motor (unplugged the service jack to remove power). However, this turned out to be wrong. The real problem wasn't related to the score motor coil, but, rather, the position of the score motor cams. When I unplug the motor jack and turn the cams by hand, I can cause the fuse to blow when the cams switches reach a specific configuration. There are 6 cam switch banks, designated 1- 6, plus an index bank cam and an impulse bank cam, eight total cams. On Skylab, 7 of the cams have a "valley" where the switch follower drops into as it rotates around the cam. The eighth cam, the impulse, has "hills" that raise the switch follower as the cam rotates. The short occurs when the switch follower of cam 1 falls into the cam valley. The cam switch 1 has the following switch functions according to the schematic: 1A: Pulses Game Over Relay. 1B: Pulses Lock Relay. 1C: Pulses Knocker Coil. 1D: Pulses 1,2, or 3 Adjust Position. I assume that one of these functions is where the short is located. Should I start unsoldering wires from the switch until I find the one that does not cause the fuse to blow? A quick look at these locations does not show any obvious problems. It's also worth noting that prior to this fuse blowing, I had been working on the score drums (reels). I took each one apart and cleaned it. This was because my numbers matching function was not working nor the "win a replay" function. Both of these functions go through the score drums. After cleaning, these functions started to working. However, after a few plays, the ball count started counting all the way up to 10 on a new game and the score motor would continue to run for several seconds before stopping. After a few occurrences of this, the fuse blew for the first time. I always tend to think that new problems are a direct result of the work I had been doing at the time they showed up. I could not find any problems in the score reels that should cause a problem. So, back to my original question, should I start unsoldering wires until I've isolated the wire that's causing the fuse to blow? Or, is there a better way to go or something to check before I do that?
Sorry for the long story, just wanted to make sure I get all of the facts on the table.