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So here's the story: Traced D4 and removed: Ram 1 (pin 16) Ram 3 (pin 16) Neo buf at ga11 (pin 2) Neo buf at ga4 (pin 2) Neo f0 at ga5 (pin 11) Tested after each removed component. When Neo f0 at ga5 was desoldered, sound turned in to a slower clicking, every 3rd second. Also: activity at D4...

I just want to report that LIR2032 has been working great on a MV1A. Board runs fine, back up data is there. I play maybe once a month on it, and on those rare occasions also let it on for a couple of hours so the battery may charge.

Thank you for the advice! I'll trace D4 more closely. But with no schematics or a working board to compare with I'm not sure how to do it thoroughly. Edit: I suppose half of the ram chips shall have a D4 line. Cpu D4 pin 1 goes to: SP1 ROM pin 15 RAM 1 pin 16 RAM 3 pin 16 ?????? Pin ...

I'm trying to fix a MV1A. The system is watchdogging with a garbage screen and click (around 3-4 clicks/second). I am using diagrom. 5V is 5.0V. When probing the 68k cpu w. oscilloscope I see: * Datalines is going high then low with each click. Except D4 which is stuck high. * Adresslines...

So far so good. I measured my LIR2032 to 3.9v when i put it in. Don't know what the charge current or voltage is of MV1a and I use my board to seldom to see what voltage the battery will reach when fully charged. But board is working fine. Btw ML2032 is 3.0 volts lithium so that is the battery...

MV1FS has a NiMH-battery and a charging circuit for these types of batteries. What I have understood is that you must not fit (or charge) a lithium battery as ML2032 in it's place. (MV1FZS on the other hand is fitted with a lithium battery from factory and can be replaced with a ML2032.)...

I just put a LIR2032 on my MV1A board. Should I replace it with a ML2032? I've read that it should be ok. But I've also read that it is not. So a good answer from someone with true knowledge would be deeply appreciated.

Update. I stumbled upon this when browsing around. Did not see this when i searched the forum. Sorry for littering with unnecessary questions. "PC = power conditioning, they re not required, them missing should not cause a click of death IIRC they are 68nF ceramic caps, but 100nF will do just fine"

This the last of 3 boards that i am working on. It is a MV1A. It is missing a component labeled "PC34" on the underside of the pcb. What does PC stand for? What kind of component is it and what value is it?

Have you tried that unibios chip on another board?

And for the record. The Neo Geo uses two 8bit chips to create a 16 bit data package. So there is no dataline above 8.

Oh Yes! It really did help me! Ive read that page many times but now i saw the links to ram locations!

Got this nice little board. With the stock bios it says work ram error write 5fa0 -> read ffa0. I have tried to interpret this. But now i need help. The first two letters differs should mean that it is the upper chip that is causing the problem. But ... Is that ram1 or ram2? Furthermore. Ive...