MVS KOF 98 dead cart ??

well I've been unable to have this MVS KOF98 working for weeks now
It was perfectly working when I received it, but since then I'm stuck with the matrix screen ... as if no cart was inserted
Cart is original SNK with nothing special to be spotted on the surface of the boards (no dry solder, broken traces, corrosion or whatever), it looks almost new actually

All contacts cleaned with eraser + alcohol (while they obviously didn't need it)
Checked on all slots of my two MV2F and nothing happens

I've collected 40+ carts now ad this baby is the only one to behave like this ...

Could it be some ROM have been altered / fried ?
what are the options to bring it back from the dead ?

Your help is much appreciated !

Also try cleaning the connectors with some very fine sand paper or (dry) green scotch brite..
Until they are a shiny color..each one

I would also try taking the cart out of the case and putting it in the mother board.
Making sure the right game board goes in the right slot.(don't let them touch each other)
The case could be warping the boards..or they may be warped.


Also,try pulling the cart out of the mother board a bit.

I have a Riding Hero MVS cart that doesn't work whatsoever..The boards are mint too.

Thank you guys for the tips !

Well, I've cleaned contacts on the slots just to be sure, but given the fact all other carts were playing fine before, I was a bit perplex about that being the solution
It didn't improve anything unfortunately
I then inserted both boards without the case and had them moving slightly as Chris1 suggested but I'm still stuck with the "Cross Hatch Test" screen

I 'm really thinking about something being wrong in some chip(s)
Is there a way I could investigate this further ?
And what could be the cause for this ?
I'd really be pissed off if it happens to other carts !!

I would say the problem with your cart is that the protection decryption of the p rom data has stopped working for some reason now that you have seemed to rule out the cart contacts. Kof98 is the first neogeo game to my knowledge that had this kind of protection. Because the bios cannot see the expected p rom data its forcing the crosshatch screen.

Try checking again aound the custom chips on the P rom board for a dodgy trace or lifted / broken pin. Maybe upload a HQ scan of both side of the PCB holding the P roms.

Raz

Thanks for the advice Raz !

I checked carefully all pins and traces, and while I thought I found some suspicious dirt stuck in Altera Chip's pins, it didn't change anything in the end ... still the "Cross Hatch Test" screen

To your request, here are thus supersized pics of the P roms area of the progboard :

* Components Side

* Solder Side

Let me know if you need to focus on a particular area.

Thanks again for your help !

I just wonder if I can see something between pins 45 and 46 of the altera chip that could be causing a short?

Raz

Yeah, true, it looks like there could be something there on the pic, but there's nothing in the way actually ...
(checked, airbrushed, re-checked, nada)

Well I've been looking for other clues since, and here's something that could be worth investigating ... or not ...

I plugged the multimeter and found out my MVS is actually running on a lower than expected voltage (around 4.6~4.7V instead of 5V) and while this causes no problem for other games, there might be a chance the crypto of KOF98 doesn't like such a low voltage what do you guys think ?

I'd like to check this but as the juice is coming from an AT power supply, it can't be adjusted, so I'll have to swap that lazy PS and cross the fingers. Strange though all others games work straight. What are other MVS games using the same crypto setup (not CMC2 but Altera Max + 44-pin P1 ROM) ?

Well I'll keep you posted on this, hope it won't end up in a nice MVS paperweight

Your help was appreciated in any case, mucho kudos guys !

Razoola said:

I would say the problem with your cart is that the protection decryption of the p rom data has stopped working for some reason now that you have seemed to rule out the cart contacts. Kof98 is the first neogeo game to my knowledge that had this kind of protection. Because the bios cannot see the expected p rom data its forcing the crosshatch screen.

Try checking again aound the custom chips on the P rom board for a dodgy trace or lifted / broken pin. Maybe upload a HQ scan of both side of the PCB holding the P roms.

Raz

Click to expand...

Thanks for this bit of help! I have a Neo Turf Masters cart that I just got today that was behaving like the KoF 98 cart in question, I had cleaned the hell out of it and look over it thinking all looked good... still wasn't working. Then looked at this thread and decided I should recheck the P rom and sure enough there were some dry points that I had missed before... re-soldered them and now all is well!



ON DA GWEEEN!!!

Would I be able to diagnose a Faulty P Rom via the unibios Cart check?