Problems with MVS 6-slot

El Capitan · Jun 24, 2004

Hi guys.
Thanks again for the help with sound on my 4-slot.
I've just picked up two 6-slot MVSs, sold as seen in the hope I can get them working:

6-Slot #1

Backup Ram Error
Address 00D00000
Write 5555
Read 5500

I've read around the site about this error, but I want to know, is there a way to fix it?

6-Slot #2

Goes straight to cross-hatch. I've put six games in it, and I don't think it's dirty connects (surely one would have worked?)
And I reckon someone has fiddled with the battery. In fact I'm sure they have cos there's some weird stuff going on.

I was just wondering, the battery is on the bottom board of #2 and if the RAM is on the top of the other board (is it?) then can I put the two good bits together?
#1 is the older style with a perforated case, #2 is a solid metal case.

Please help!
thanks
John

lill-c · Jun 24, 2004

I have a 4 slot that just went into the cross hatch screen. It is still out for repiar sence Feb. I don't know if it will ever see home.

thegreathopper · Jun 24, 2004

El Capitan said:
Hi guys.

I was just wondering, the battery is on the bottom board of #2 and if the RAM is on the top of the other board (is it?) then can I put the two good bits together?
#1 is the older style with a perforated case, #2 is a solid metal case.

Please help!
thanks
John

The Ram chips are also on the bottom board, but you will do no harm trying the different bits together, It doesnt work anyway...

El Capitan · Jun 24, 2004

The battery thing looks really weird. Someone has replaced the regular round battery with an odd shaped one, and there are leads trailing across the bottom board to a switch (like a joystick microswitch) by the dips.
W-E-I-R-D!!!

El Capitan · Jun 24, 2004

Hmm I've been trying out a few things, on the board with a ram error, I tried connecting 3V in parallel to the battery (I think it's dead) with no luck.
The one with the microswitch across the battery is still confusing me - anyone ever heard of this before???

I guess I'm after help ideally to get both working, but if one has to be sacrificed, I may accept this.

thanks in advance guys

John :help:

ttooddddyy · Jun 24, 2004

El Capitan said:
The battery thing looks really weird. Someone has replaced the regular round battery with an odd shaped one, and there are leads trailing across the bottom board to a switch (like a joystick microswitch) by the dips.
W-E-I-R-D!!!

The microswitch is an after market add on. Its a reset switch, which disconnects the battery and puts a load on the supply from the battery in order to reset memory- disconnect it and remove the battery for now.
I have seen this on MVS boards before, but its rare.
There was a thread on it a while back-unable to find it now.

El Capitan · Jun 25, 2004

So I should take out the battery altogether? Surely the system needs the battery for something?

And What else can I do to get my babies working!

ttooddddyy · Jun 25, 2004

El Capitan said:
So I should take out the battery altogether? Surely the system needs the battery for something?

And What else can I do to get my babies working!

Yes you can take out the battery altogether.
The board will work perfectly OK without the battery, what it means is that it boots up with default settings, so if you want red blood you have to go back in to soft dip to set it up. Also obviosly the callender doesnt work. Otherwise it does not effect the operation of the board, what it does, is eliminates a potential problem.
When the battery is removed check that there is no leakage on the board that may cause corrossion, this is common, remember these batteries may be over ten years old and Ni Cads are reknowned for leaking.
None of my MVS boards have batteries fitted at the moment- just havent got around to fitting newbies. Just a slacker I guess.

El Capitan · Jun 28, 2004

Ok, I'll take the batteries out later today.
Do you expect this will solve anything?

Any ideas about the backup ram error or the crosshatch stuff??

El Capitan · Jun 28, 2004

Ok, This post is about the board with the weird reset button.

I snipped out the battery and all seems ok, no spillage.

No matter what I do I cannot get it to boot to anything other than the cross hatch. I have seperated and re-attached the boards many times now, I've even used the top board off my other six slot, but still no joy.

It goes to cross hatch whether it has the top board attached or not (as in I've connected the jamma loom to just the bottom board, and I get the same effect as with the top board attached in place.)

Also there is a red and black wire to connect the two boards, as well as the four edge connectors on the PCBs. Are there any other connections that should be made???

Help me out here please anyone!!!

ttooddddyy · Jun 29, 2004

El Capitan said:
Ok, This post is about the board with the weird reset button.

I snipped out the battery and all seems ok, no spillage.

No matter what I do I cannot get it to boot to anything other than the cross hatch. I have seperated and re-attached the boards many times now, I've even used the top board off my other six slot, but still no joy.

It goes to cross hatch whether it has the top board attached or not (as in I've connected the jamma loom to just the bottom board, and I get the same effect as with the top board attached in place.)

Also there is a red and black wire to connect the two boards, as well as the four edge connectors on the PCBs. Are there any other connections that should be made???

Help me out here please anyone!!!

"Goes straight to cross-hatch. I've put six games in it, and I don't think it's dirty connects (surely one would have worked?)"

You shouldNever assume that, I have a couple of 6 slots, and had similar problems to start with on both board sets, changing dozens of carts in various slots = still cross hatch only.

Only when I really cleaned both carts and slots properly did things start to come together.

http://www.hardmvs.com/html/slotCleaning.htm
http://www.hardmvs.com/html/cleaning.htm

El Capitan · Jun 29, 2004

Hmm ok, but it has really pissed me off in the past taking hours to thoroughly clean a machine for no benefit!

I already know the games work cos they're fine on my four slot, so it could only be the board, but I've tried both top boards with all slots filled with no joy.
I'll still give it a go later. Fingers crossed!

I also read that The uniBIOS can get around some errors, so I've asked Razoola if version 1.2 (which I have already in a 4 slot) will work on the Backup ram error.

Razoola · Jun 29, 2004

v1.2 will also allow a continue from a backupram error, the problem is that on multislot hardware the backupram is used to store info of every game in the 6 slot at start up. Because the backup ram is bad that will likley cause a crosshatch also even if the system is reading all the cart data correctly.

I think what you need to do next is on the board that goes to the crosshatch screen is to turn all hard dips on and power on. This will force a backupram and work ram test. This will be a good way to see if the backup ram is ok on that mobo at least.

Try the unibios v1.2 on the system with the backupram error and at the error screen press the button that allows the system to continue and see how far it gets. Its very likley it will get further in console mode than arcade mode if it runs at all.

Because of the actual error you are getting it would seem the low byte of every word is gone in the backupram. You could swap a ram chip from the other pcb to fix the backupram error. Maybe its a cause that all the faults lie on the bottom pcbs and both the top pcbs are good, who knows.

Raz

El Capitan · Jun 29, 2004

Thanks for the quick reply Razoola,

Well I've cleaned all evening and I'm thoroughly pissed off cos the board still isn't happy. :mad:

The board that went to the cross hatch still goes to cross hatch (although slightly quicker if I have the UniBIOS in. However the UniBIOS screen doesn't come up - just straight to cross hatch. Any ideas?)

However a few times I got :::::
Work RAM Error
Address 0010001E
Write 001E
Read 801E

Any ideas?

The board with the RAM error is still fuct. I tried the uniBIOS in it and it came up with the error message, so I pressed A to continue and the screen goes green, then back to the UniBIOS ram error message. I can't get to the UniBIOS menu.

Help!

Razoola · Jun 29, 2004

I'm not sure but I think its beginning to look like you'll have to use one board as parts to fix the other. I think going from what you just said your going to be better off fixing the pcb with the initial backupram error by taking the RAM chips from the other pcb. You'll probably only need to replace one chip but I'm not sure which one that will be from all the RAM chips on the PCB. The constant reset on that pcb with the unibios in is most likley due to an address error caused by the bad backupram only.

Raz

El Capitan · Jun 29, 2004

Oh no! I'm guessing a regular guy like me can't do the type of soldering necessary.
Or is it simple (i.e not flatpack which i hear is sooooo tricky!)

Nightmare Tony · Jun 29, 2004

The first error would indicate an entirely dead low byte backup RAM. The new errors you atre getting are more the random errors associated with a floating line to the RAMs, possible the enables or writes.

The work and backup RAMS are all flat pack, so if you dont have experience or comfortable with those, send out the board for repair.

For the crosshatch, that simply means that the system is not revcognizing the cartirdges. I forget the entire set of variables, but the system must be able to recognise the "NEO GEO" in the program header.

so anything that works with the address and data is suspect. Did you try switching the top boards and still the same thing? Maybe the buffers on the bottom board, mainly 244s and 245s. rarely do I find them bad, more likely, I find scratches or gouges on the bottom of the main board which snaps open traces, causing that or other things...

El Capitan · Jun 30, 2004

Hmm well I think these babies are going to go on eBay.

I was really hoping I could get one of them working at least...

Nightmare Tony · Jul 1, 2004

The only thing I ask of you, be honest when you put it up. Tell exactly what is wrong and go from there. I hate seeing when someone says "100% working" then I have to fix after. That results in bad feedback, bad reputation...

El Capitan · Jul 1, 2004

I expect I'll put a link to this thread - hopefully someone might be able to use them for spares or repair.
I might advertise it in the Neo selling section first.

Problems with MVS 6-slot

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