I purchased a DESW game a while back and have been plowing through the issues one at a time.

Someone removed the knocker solenoid from the game. I purchased a replacement from Marco. Did a temporary wire job to test it out. Ran the diagnostics. Coils tested for a few cycles, then suddenly the flashers started flashing, one of the coils got stuck open and started smoking so I immediately shut it down. I found out that the transistor for the flashers was fried, this is the same circuit shared with the knocker. I replaced the transistor and the flashers seem to be working now but the LED bulbs are toasted on that circuit. I also found that another transistor in the same row had been replaced by someone else. A melted connector and scorched board.

From the posts, it seems like a lot of folks have problems with the knocker for some reason. I don't know why the other person removed the knocker, if it broke or if there is some other issue going on which is what worries me. It is possible that I connected the wires backwards on the knocker, but would that cause this type of issue? I am thinking something was wrong long before I got the game. Any suggestions on what to check would be appreciated.

I am getting 39V at the hot side and 32V on the backside of the bulb on the flasher circuit.

I just realized flashers are supposed to be 18vdc not 39vdc! Bad power supply?

I just checked the schematic and says 32vdc to flashers. I get 39v to orange wire and 32v to ground side. Is that still high?

Anyone out there that can lend a hand?

So I continue to learn and read any pinball info I can find. I know that the main transistor blew and also the secondary 2n4401 which I replaced both. So, flasher/knocker circuit still does not fire, it has power and can manually be test fired but no work. Those two are in paralell. Btw, before I replaced the larger tip transistor, the flasher would not shut OFF.

I also have another flasher circuit that continues to get low power and backbox flashers stay partially lit- 4-6 vdc.

Lastly, some fantom game actions happening, skill shot happens by itself with no ball launch.

Time for professional help??? Is their a place to send in the board? Does it sound like main board or power board?

Thank you in advance, hopefully someone chimes in.

Thank you for your reply! Sounds good on the bulbs and reseating the chips, did not try that one. All fuses are good. There is power to both the flashers and the knocker, so assume has to be in the board area.

Hi Chris, the knocker transistor was definately fried. The parallel flasher circuirt was stuck on. Replaced the tip and 2n transistor according to pinball repair manual. Now flasher off but wont flash ans knocker stil no knock. I suppose there are dozens of other components that could also be fried. Unless there is an easy suggestion, i will probably pack up the boards. I found some prior tracer repairs so who knows what went on. Thanks for your help.

Got it! I will send cpu and power board.