Stern Hot Hand (Stern, 1979) Noob Needs Help

[pin4fun]

Hi All, first post here. I don't know much about working on pinball machines but I'm trying to learn. I recently bought an old Stern Hot Hand machine. The game worked OK for awhile other than locking up sometimes if it had been on for a long time. Now I'm getting nothing at all. The MPU light comes on and then blinks 3 times, the big spinning flipper at the top of the machine twitches a little and that's it. I've noticed a couple of things on the back board that I don't understand.

First, there is a red wire and a white wire that were taped together, I took them apart for the pics. Looks like they were both soldered to something or each other at one time. The white wire appears to go up to the plug for J1 on the MPU board. The red wire appears to go down under the playfield to a plug on the rectifier board. Why would 2 different color wires be taped together and what would they have been soldered to? I don't see anything in the area that they would have been connected to. Is this correct or is it some kind of hack job?

Also the scoring and player lights work but not the ones behind the backglass. I tried new bulbs but still nothing. On the back of the board are 2 wires, white and blue, that run from one light down to another. Is this normal or a hack job or what?

I don't have a voltmeter but I'm going to pick one up tomorrow. Where would you start with this? Thanks for any help you can give me.

 

[faralos]

if that's an ol dEm then that's about right. most of them were hand-wired at the shop by one person usually and some of them were indeed ugly to look at!

 

[mrschultz]

Looks to me like the lines feeding those top lights stopped working, and instead of fixing the problem someone ran a jumper to the bottom row. If all those lights run off the general illumination power supply there's no problem with the jumper, but if they are run off a blinker circuit it could be that putting too many bulbs onto one circuit killed it.


There are some schematics at the internet pinball database, but you're back box looks different than what they have.

 

[faralos]

ok taking a better look at that second pic, he's right. that wire does indeed jump from the lower line to the upper line of lights. so somewhere in that upper line of lights there probably is a short, so someone just jumped it across so they lit up (while trying to sell it most likely)

 

[pin4fun]

Thanks for the replies. That's about what I figured on the lights. I'm more concerned about the red and white wires that were taped together. Is this connection incorrect or is it just a poor way of doing it? BTW, Hot Hand is a SS machine from '79, not an EM. Thanks for your help.

 

[faralos]

of course it's incorrect, if anything a soldering job wrapped or 'twist-capped' would have been safer! but do not connect them back until you find out why the lights were taped together in the first place! (don't touch the machine when playing with them just in case...)

 

[mrschultz]

Thanks for the replies. That's about what I figured on the lights. I'm more concerned about the red and white wires that were taped together. Is this connection incorrect or is it just a poor way of doing it? BTW, Hot Hand is a SS machine from '79, not an EM. Thanks for your help.

My guess is the red and white wires were originally attached to the top row of lights, there doesn't look like anything else at the proper distance for them to connect to. When they died someone probably just taped them together to get them out of the way and ran the jumper to the bottom row of lights.

They look like original wires from the harness, so it's very unlikely they were run up there just connect to each other. You just wouldn't change color in the middle like that, and the way they look suggests they were soldered to something flat.