Well, if you are looking for a high quality print repro this link might be interesting: https://zonaarcade.forumcommunity.net/?t=63308481#entry469533231
Wish I'd found it earlier :)
Thank you! I like to inform that I've also found this site: https://zonaarcade.forumcommunity.net/?t=63054589#entry469529514
There are a lot of other nice repro work. Site is mostly in Spanish but users seem to respond when writing in English. Could get his variant for 15 eur so might try that...
Got a cage that someone have tried to paint white. I'm looking for the cage stickers for this system.
I was surprised I couldn't find it. A scan of the cage would be a dream to work with :)
I have circled the stickers I'm looking for. Picture is not showing my board.
Please help :)
Neo Geo MVS. Bought as non working. Seller said it randomly booted with Unibios IF a cart was inserted.
Board looked nice and clean. Someone had obviously tried to fix it. New backup-rams, U4990-chip had shiny solder. All hot glue (which is from factory to avoid vibration) was removed. New...
Used a printer that could do A1 at a local print shop. Noticed that the windows printer manager somehow expanded the image so I had to cut sides to make it fit.
Comparing with a picture from the internet (tm) it seems that there are multiple versions of this marquee as the one from @nem has...
It all started fairly innocent:
Color ram error 0002 vs 000A
Scraping sound from audio output.
Scoped pins on palette ram. And sure enough pin 15 "I/o4" on ram 7 had a dc offset of 2.2 V. Offset not present on pin when probing it lifted from circuit. So something was corrupting its signal...
They are complicated thats for sure. I'll write a complete repair log of this where i present the pinouts I have made. This board has gone through some extensive surgery.
Finally this little quest seems to have come to an end. Today I got sound on KOF'99, RBFF and metal slug x.
I have fixed a couple of mvs. But mostly easy stuff like ram errors. I have no deep insight in the architecture. But here is what I did ...
I compared how the prog cart pins and pcm chip...
Checked connection between main- and slot pcbs. Found some missing connections.
Edit: fixed these but no luck chuck. Exactly the same behaviour.
Was it really bad connections or did I just do something wrong when I measured?
Am I going insane?
Small update. Swapped slot pcb with known working board. Result: slot pcb is not the problem.
Probing pcm chip on KOF'99. There is a lot of dead data and adress lines. Could it be that the m1 rom isn't properly executed?
Suspecting Neo buf at GA9 but also zmc2. (My zmc2 is a new repro but...
One thing I noticed is that some of these NEO-BUF repros have solder between the legs on the super tiny ls245 chips. There is quite often a short between the NC on the chip and its neighbouring pin, but this seems to have no matter. But sometimes the data lines are shorted...
(This is no...
Is it possible that a faulty Neo buf at GA4 can interfere with the data bus on GA9? They are in parallell after all.
I replaced my buf at GA4 and that made a change on my comm isssue. BUT that also might've been a pure coincidence since I got multiple different errors after that change.
(I was...
Finally some progress. I've checked all latches and their data lines with certain regard to floating signals. But no findings.
Decided to change my furrtek repro at GA9 "because it just had to do something with that chip". But by now i had run out of repros. So I used the snk one that used to...