Lighting Sequence advice on EDOT

cwstrong

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Lighting Sequence Always On - EDOT - SOLVED!!!

My lighting sequence PCB ( on my EDOT is making all strobe bulbs stay constantly on with the R10 resisitor overheating. All lights are on, but have constant current instead of a strobe effect when Sark gets killed. All MPS2222A transistors are new. Any suggestions on what's creating the always completed circuit?

Thanks in advance
 
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The last one I worked on had all the parts replaced except that chip. I couldn't get a new one. The lights just stayed on for me, too...
 
The last one I worked on had all the parts replaced except that chip. I couldn't get a new one. The lights just stayed on for me, too...

What chip are you referring to that you couldn't replace? Was the resistor at R10 overheating as well.

Thanks for the reply.
 
What chip are you referring to that you couldn't replace? Was the resistor at R10 overheating as well.

Thanks for the reply.

I think I replaced that resistor with a 5-watt one to reduce the overheating.

There is a socketed chip there that is a special ROM. I don't think the code is dumped anywhere to get a new one burned...
 
Solution Found!

I think I replaced that resistor with a 5-watt one to reduce the overheating.

There is a socketed chip there that is a special ROM. I don't think the code is dumped anywhere to get a new one burned...

My problem ended up being the IC 7406 located at U1. It was faulty which led to the closed circuit which constantly illuminated the lamps and overheated the resistor at R10. Replaced the 7406 chip and sequencing is good as new! :)

FYI - After initally thinking my U6 may have been originally at fault, I did get a PROM burned by Bob Roberts for U6 from a MAME file I found online. Although the new chip sequences the lights, it sequences them in a random cycle instead of up and down or vice versa. For those needing a new U6 PROM chip, it's better than nothing. PM me for the file, if interested.
 
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EDOT Lights

My lighting sequence PCB ( on my EDOT is making all strobe bulbs stay constantly on with the R10 resisitor overheating. All lights are on, but have constant current instead of a strobe effect when Sark gets killed. All MPS2222A transistors are new. Any suggestions on what's creating the always completed circuit?

Thanks in advance

Congrats on getting the lights fixed. About 2 years ago I came across an article on bullet proofing the sequencer PCB by replacing the MPS2222A transistors with TIP 122's. Here's the link to the article: http://girasoli.org/arcade/?p=202
I made the change and haven't had a problem since.
Rich H
 
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