Topic: Neo Geo repairs  (Read 2116 times)

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Offline DEL 707

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Neo Geo repairs
« on: October 13, 2014, 06:42:10 PM »
Hi, not sure if this is the right part of the forum to ask this.

I have 2 Neo Geo MVS boards, a MV1-FZS and a MV1-FZ.

The FZS was working fine for about 6 months then 1 day I turned it on to play a game and while in demo mode, it kept playing game music during the Neo Geo splash screen. I did a reset and was rewarded wit.h a Z80 error message. Thankfully someone burnt me a Neo Geo diagnostic roms, I threw the M1 rom onto a Super Sidekicks cart.
 Unfortunately it didn't tell me much other then there was a Z80 error. I did some continuity checked on the 6116 RAM and looked over the board for some damaged tracks, but everything seems fine. I took the board into work and my boss dusted off his old oscilloscope and had a look, he used to repair Amstrad's and Amiga's back in the day, sadly no Neo Geo's.
 Didn't have much to go on, but he thought Data Line 6 looked wierd compared to the other data lines.



Long story short, I gave up and decided to buy myself a new MVS, a MV1-FZ board from Korea.

The board turned up and never really worked from the start, again I have no sound. So I put in my diagnostic bios and cart, this time I don't get any kind of Z80 error, but the diagnostic rom gives me a M1 Bank Error.
 I did some reading and was advised to check continuity again on these points.

Quote
NEO-D0 SDRD0 (45) ? CHA SDRD0 (MVS: B47)
Z80 A15 (5) ? CHA SDA15 (MVS: A58)

Again this check out fine.

I'm a bit stumped on what to do, so I was wondering if anyone here has some advice, or knows a repairer in the UK that will look at Neo Geo's.

I know it's probably cheaper to simple buy another, but I am worried about something in my setup causing the problem. I've done the wiring myself rather then use a super gun and I'm using a JAMMA PSU that has a variable 5V. I have checked the 5V line and it's still only about 5.04V with a load on.

I appreciate any help.

Offline Spirantho

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Re: Neo Geo repairs
« Reply #1 on: February 04, 2015, 08:53:31 PM »
Did you try changing the Z80?

I could probably look at it but I can't guarantee a repair and I'm not sure about the cost (probably £30-£50), and it may take me longer than usual as my own Neo Geo AES is fortunately still working perfectly *touch wood* :)
Ian Gledhill
ian@mutantcaterpillar.co.uk but with a hyphen between "mutant" and "caterpillar"
Mutant Caterpillar Games - vintage computers and games in our shop!
http://www.mutant-caterpillar.co.uk/shop/