Hi David,

I usually try to isolate things. For the Heat Wave, If you're talking about the GI lighting, I'd try and unplug the back box connector that carries the lighting power and return. See if the playfield lights go back to their correct brilliance. Or vice versa, disconnect playfield lighting and see if the back box lighting works. That could help isolate where the short is. Did this problem occur after some other work done? Retrace your steps from that job and maybe find the short. It's pretty easy to bend something and create the short. I know reaching around inside my machines my sleeve gets caught on things and could potentially cause problems. I've created more problems trying to fix other problems. Good luck

Divide your problem into parts.

A frequent problem is a string of General Illumination lights that causes the fuse to blow (in your case, be using too much power).

I'm not familiar with EM's as much as I am with more modern pinballs, but each string connects to a connector, right?

So, I have my diagonal cutters, and my soldering iron, I have a circuit breaker that is soldered to a blown fuse. If the General Illumination is normally a 5 amp fuse, my circuit breaker will be a 4-amp... it won't blow unless there is a problem, but it'll blow quicker when I'm testing. Alternately you could use a couple boxes of fuses to do the same troubleshooting.

The trick is to cut out a section, and see if the problem still is there.

So if the General Illumination has plugs for the backboard, and the playfield, I'll disconnect the backboard, and turn on the machine... do I still have a problem? If I'm now not blowing the fuse (dimming the lights) on the playfield, I know my problem is on the backboard.

So now I connect the backboard and disconnect the playfield. Turn the machine on, do I blow the fuse (dim the lights)? This confirms the section is somewhere in the backbox lighting.

Now I use my wire cutters. The idea is to make your cut where you can easily take some solder and bridge your cut with solder to reconnect.

I try to find a halfway point. Suppose I have two strings, of eight lights each. I'll make my cut to take out one of the two strings, turn on the machine, do I still have the problem? That isolates it to one string.

That string has eight lights. Find the middle point. Cut there. Do I still have the problem? I know it's one of the four remaining lights in the circuit. Or, I don't find the problem there, I use some solder to bridge the cut I made, and reconnect the other four lights, but now I cut halfway between the ones I know the problem is in.

Divide the problem by two when possible, have some way to identify where the problem is (easy if it blows fuses!), be ready to solder things back together as you complete each stage.

It's tedious, but this is how you do it.

Yea, divide and concur. I first do a visual inspection and since its a slow burn you can feel along looking for the hot spot? (Maybe its all hot). So after 10 minutes of looking at socket tabs etc I start desoldering pieces.

i have a service call today with a Bank-a-ball blowing the lightbox lighting fuse quickly... Im betting that the exposed wires of the score reel lighting is the culprit. I also have a 15 amp mini circuit I'll substitute for the cartridge fuse.

With the general illumination shorts, usually a shorted lamp socket can be pinpointed by the brightness. Lamps near the short are dimmer than those further away. And if all playfield GI is equally dim, then the short is probably not on playfield.

Incomer, So if the backbox lights are at full brilliance and only the playfield lights went dim, I don't think you have a short. All the lights use the same 6vac tap on the transformer. If there was a short, all the lights in the machine would be dim. I'm inclined to believe you have a contact problem with the connector that supplies the 6vac and common to the playfield. If those pins are dirty or corroded they add excessive resistance to the circuit. That resistance can drop voltage to the lights causing them to dim. It can also heat up the connection which could cause the fuse to blow. If there is a separate fuse for the playfield lights, I'd check the fuse holder for corrosion too. Like 'pinretail' mentioned and I've done the same, I soldered a circuit breaker to a blown fuse. Inserted this circuit breaker assembly into that fuse holder. Now the breaker will trip instead of blowing a bunch of fuses. When the problem is fixed, then put in a good fuse. Report back with your findings. Good luck.