I just recently inherited my first pinball machine, 1979 Gottlieb Pinball pool system one machine. I have since then been trying to learn everything I can about this machine and came across this forum. There have been a few minor issues that have came up since I began playing it. The biggest one being that when the machine is turned on and left on for more than a half hour or so something happens and locks up the game and all of the score displays turn off. At this point none of the controls work and putting in another quarter and pushing the play button does nothing. I have found turning off the machine and unplugging the power supply board to CPU board cable and re-attaching it seems to be the only way to get the machine to work again. Simply turning it on and off does nothing and by process of elimination I determined it by unplugging that A1J1 power cable from the power supply and then back on stops the problem temporarily until another half hour or so when things have warmed up it will do it again.

I thought it was possibly the cable so I have replaced the A1J1 mpu power cable and also the A1J5 to A3J1 cable with new ones by docent electronics. Unfortunately this has not fixed the problem.

Can anybody recommend any possible causes of this lockup problem? Its almost as if once the machine warms up it locks up. I have contemplated replacing the power supply board with a rottendog replacement and possibly even the driver board as well just to try and rule them out.

2nd issue is that one of the (2) pop up bumpers does not work. I checked it out and could not see any signs of a switch failure or burn marks on the coil. Any ideas what to check on a system one pop bumper?

Thanks for any help/suggestions offered!

Tom

Thanks for the replies! I read the pinrepair guide, its quite extensive and quite a bit to take in. I'm totally new to pinball machines and soldering electronics so this is a big learning curve for me. I have all intentions of getting this thing running good and never realized how fun it would be to own one. The ground mods don't look too hard to accomplish aside from the whole soldering part. As far as replacing a transistor, i'm assuming they are also soldered in? I might go ahead and drop the money for a new rottendog power supply board and driver board for $135 shipped.

I will see if I can find any obvious problems with the pop bumper. Are the pop bumper switches and coils fairly simple to replace? From what I understand the system one games pop bumpers were not controlled by any circuit boards. So something mechanical must be wrong with it.