Direct Galaga board replacement options?

bonedoc

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Ok, here is the story. I sold my MINT galaga upright mini to a friend of a friend. It work GREAT, but occasionally had a RAM 4L error. Well, they got it home and played it a couple hours and got the error. They know NOTHING about electronics, yet decided to pull the board out. They found a PCB label that said 4L and they pulled the chip out to "clean it". This wasnt even the correct chip, as 4L is actually the PROM on the video board.

Unfortunately, they broke off legs. Im also pretty sure that they either damaged something else, or originally put the chip in backwards and powered it on. Nevertheless, nothing works. I just get a white screen with a few odd blocks of color.

I took the unit home and tested the voltage from the power supply, and it was 1V low. So, this was most likely the original problem. I repaired the broken pins and put a new socket in the board, in case this was part of the issue. I also put a nice power supply in that is putting out just over 5V. Still the same problem...

I think that they created a short in something on the video board. What? No clue. I can say that the power supply acts totally fine with just the CPU board plugged in, but as soon as I connect the video board to the CPU, the voltage drops by close to 1V and a short is sensed.

So....I have pulled all socketed chips out and still have the same symptoms. I dont think a chip replacement will solve my issues.

The buyer agreed to buy and new board and I will put it in. What are my options?

Honestly, I am hoping for a modern replacement for the old board. I usually work on pinballs, and dont understand what Jamma is. I could get the original, but would like to avoid that. I dont mind multicade, but the galaga joystick is only bidirectional.

Any advice?
 
Ok the easy question first, what is jamma;

http://www.jammaboards.com/jcenter_jammaFAQ.html

Next I am not sure about the mini and does it take the standard size pcb's or is it a different size? I have had very good luck with the video board and they are fairly easy for me to fix. I haven't seen a mini before so I would like to see a pic of the bad video board. You most likely have a short on the board or a chip. They are not too hard to find but you have to remove chips from circuit to find the problem child. There are a few ways to do this the one I usually use but don't like it much, cut the trace to a bank of chips until the short goes away. I don't like this much but it is quick and not real hard to put back. The draw back to this is if it is not a chip but a lifted trace making contact to something it should not. I would say look at what has been done to the board and talk to them about what they did to the pcb's. Ask them several times but in a different way, judge Judy comes to mind here. Find out how they got the chip out and with what. Try not to get them upset or they will stone wall you and there will be no more useful info/intel.

The best bet at this point is to give the board a good look over and interview the 'tech' that worked on it to find out the methods use to 'fix' the board.
 
Ok, so the mini upright is exactly the same as the other 2 models. The cabinet is the only difference.

I did pullout ALL socketed chips and still have the short. I did find one resistor array that was a little odd. I removed it, but no luck.

I think my best bet is to go with Jamma. It looks like there is an adapter for galaga since it was made before 1985. So, I guess that leaves me with trying to find a galaga only jamma. I don know of any other games that have a joystick that only does 2 directions.
 
Ok, so the mini upright is exactly the same as the other 2 models. The cabinet is the only difference.

I did pullout ALL socketed chips and still have the short. I did find one resistor array that was a little odd. I removed it, but no luck.

I think my best bet is to go with Jamma. It looks like there is an adapter for galaga since it was made before 1985. So, I guess that leaves me with trying to find a galaga only jamma. I don know of any other games that have a joystick that only does 2 directions.

Take a quick look at c1 on the video board that could be the issue and there is only one electrolytic cap on that board if I remember right.

EDIT:
Where are you located, I am currently visiting family in Minnesota and if you are on the way back to MD I could stop in and take a quick look at the pcb or at least narrow down the short 4 U.
 
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