Hi guys, I'm having switch troubles with the 4-bank drop target assembly on my Dr Dude (System 11).

All of a sudden the behaviour started where the bank would take one hit from a ball on any target and they'd all register as being it. And occasionally nothing would hit the drop targets but hits would be registered (indicated by the flasher and 'bling' sound when bank is completed).

My first thought was a bad diode so I took apart the assy, cleaned the optos, checked the diodes and they are all fine. I inspected all the solder points on the board and none looked to be in need of reflowing.

I put the assy back in the game to test after cleaning and the behaviour persisted.

In switch edges test the following happens:

If I drop target 4, it registers a whole bunch of 'target 4' in rapid fire. If I drop target 2 it registers it, but also triggers several 'target 4'. Other targets mostly don't register at all.

If I knock on the playfield near the targets I can get target 4 to register as well.

Question: should I reflow the solder points, or is the actual opto for target 4 (and possibly others) likely the culprit?

Cheers in advance for any help

Sounds like a good idea. Especially considering that four of those optos from Marco is more than the cost of the whole Great Lakes board! I'll tinker around a bit more, reflow some solder and reseat connectors then order the board if I have no luck.

Cheers!

A friend replaced the LM339 chip on this board for me and it hasn't resolved the issue. I don't understand how one dodgy opto can affect all the others, and I don't know how to test which opto is the one at fault.

Can anyone advise how to further test what might be the problem with this board?

I'd rather not pay the expense of a replacement board plus shipping to New Zealand if I don't have to.

And before doing so I'd like to be sure that no other components in the back box could be causing it. Is this a possibility?

Cheers.

Bump