EDOT light sequencer

modessitt

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I had no lights, even though the bulbs were good. I replaced all of the PN2222A's with TIP122's (doing the leg twist to match BCE pinout of the PN2222A) and now my bulbs light but they don't sequence in test.

I've had this problem before, and we thought it was the PROM on the light sequencer. We were never able to find a way to get a new PROM to see if this was the case. As it is a very small chip (7603), and the fact that I don't know if anyone has even dumped the file, I'm not sure how or whether it can be replaced easily.

Anyone have any thoughts?
 
I want to say that someone had a thread about it but I can not find it for the life of me. I just remembered something to the effect of Mame; code and reprogramming of a chip.

I would be interested in knowing the fix too because I have the same problem on my chopped enviro also.
 
The transistors and resistors are really really sensitive on that board. If you have the wrong light bulbs you'll blow the transistors/resistors.
 
The transistors and resistors are really really sensitive on that board. If you have the wrong light bulbs you'll blow the transistors/resistors.

Yeah, I know. I have #161's in it as expected. I saw your site, but you didn't go to indepth on the repair stuff.

Most of the "repair tips" I find all talk about replacing the transistors and everything working. This has not been the case for two of these so far....
 
Found the old post. Not sure if it is relevant. I would love to get my hands on that U6 file also to get a PROM burned too.

http://forums.arcade-museum.com/showthread.php?t=101076&highlight=edot

cwstrong provided the info:

"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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