MVS Error Message Question

I finally tested my MVS... (just recently got the connector.)

And well... I plug in various cartridges and such and I get the following error message:

Video Ram Error

Address Write Read
00008000 5555 0000

It's a 2 slot MVS board.

On the harness I've only wired it for video (Video Sync, Ground, R, G, B) and power (+12V, +5V, Ground).

I've got 2 joysticks plugged into the joystick ports, and two carts in the 2 slots, a connection on the headphone jack and no memory card.

I have tried with the dipswitches with "test" mode off and on. And for the hell of it tried it with "free play" and "pause" modes off and on. All the same results. The error message pops up with or without carts, or anything other the the harness plugged in.)

I was told by MDGamesSales that this unit was tested when I bought it but it's been over a month (maybe 2) since I initially bought it and they tend to have a 14 day warantee type of agreement. (Hopefully something can be worked out.) But before I try I want to make sure it's not my fault.

So did I get a big paperweight or could this have something to do with an inadequate power supply? Do I have to hook up something else in order for this to work? (IE: the following isn't connected via the harness: the test switch, the coin slots, coin counters, the joysticks, the sound.)

<img src="graemlins/help.gif" border="0" alt="[Help]" /> would be appreciated.

Thanks.

[ August 07, 2002: Message edited by: td741 ]</p>

Anyone?

Check all the soldering on the motherboard, and see if any of it is loose and/or rusted. Also, check the MoBo for burns or any other strange markings. When you are checking your MoBo, make sure to hold it by the edges, and try to avoid touching any of the metal connectors. (Static is bad)

with hardware you're almost never going to really see burns or anything like that. I would start by getting a multi-meter out and checking the voltages.

What are you using as a power supply? Does the voltage drop when you turn the unit on? is there a crossed wire in your 5 volt wiring? Are all the grounds seperate or common?

The best thing to do is answer all those questions for yourself and make sure that you are providing the right voltage, with enough current, to do the job. Also, be careful of +5 and -5, sometimes people get those backwards and, in spite of popular beliefe, hardware doesn't always go up in smoke, it usually just doesn't work.

Some stupid little things to check could also be making sure the contacts are clean and that the cart is in the right way. Don't take these suggestions as insults, I've done dumber things than you can possibly image.


edit: someone else said they had this problem and it was a dip switch that was left on. I would get in contact with him and ask if it's the same error and wich dip he changed.

also, there's always <a href="http://www.hardmvs.com" target="_blank">www.hardmvs.com</a> for any hardware help you might need.

hope all this helps! :-)

[ August 07, 2002: Message edited by: m_bish0p ]</p>

Also, make sure that you arent using a bootleg cart, those can give you errors. But still, like previously mentioned, be sure that you're providing the correct ammount of voltage.

Carts aren't the problem. I've tried 6 of them, and I even tried without any. The results the same. The error seems to be during it's POST sequence (testing video). There's a brief grid, a burst of colour and then the error message.

It could be a power supply issue but first I need to dig out my volt-meter (moved recently). Umm... Actually I might need a new one anyway. (Argh, gotta wait another week 'til payday.)

But would that type of error happen with insufficient voltage? Seems a little weird. Is the +12 line used in the 2 slotter? If not then I might try some other means of supplying power.

(Using PC power supply).

Seeing at the problem occurs specifically on "Video ram", I'm guessing that it's nothing to do with the cart, sound, etc. Anyone know where the video ram chips are on the 2 slotter? (Or what the ram chips look like? I do remember seeing one chip that might look like the leg got damaged (didn't look at it too much) but I think it was near the joystick ports so I figured it wasn't it.

If one of the pins didn't get any power, would the whole system not work?

Thanks.

Sounds like a dead board my friend. Could be wrong, but I don't think I am.

Peace

JHendrix

Dipswitches?

Well, there are 8 right. When I started, one of them was on (Dipswitch 1) which is reserved for "test" mode right? I turned it off and same thing happened.

I tried it with freeplay on, off. And then with the pause dispswitch on. Tried different settings and nothing helped. I'd figure the pause one would cause something but nothing there (error message popped on). Seeing as the error message popped up, I figure that this happens before the dipswitches are checked?

I really hope that this isn't dead.

[ August 07, 2002: Message edited by: td741 ]</p>

Its not the cart or the the power... Its on of the chips on the board.... I have seen this on the tech board before.... Do a search for that error

EKW

Duh... That's where the search is.

Found these:
<a href="http://www.neo-geo.com/cgi-local/ultimatebb.cgi?ubb=get_topic&f=5&t=001847" target="_blank">http://www.neo-geo.com/cgi-local/ultimatebb.cgi?ubb=get_topic&f=5&t=001847</a>

<a href="http://www.neo-geo.com/cgi-local/ultimatebb.cgi?ubb=get_topic&f=5&t=001710" target="_blank">http://www.neo-geo.com/cgi-local/ultimatebb.cgi?ubb=get_topic&f=5&t=001710</a>

<a href="http://www.neo-geo.com/cgi-local/ultimatebb.cgi?ubb=get_topic&f=5&t=002001" target="_blank">http://www.neo-geo.com/cgi-local/ultimatebb.cgi?ubb=get_topic&f=5&t=002001</a>

Now I've got to see if my buddy can help me with those.

ARgh... I'll see if I can spot the chips at least.

Edit : Nevermind

I wasn't trying to undermine your abilities, it's just that with an MVS the power-supply is off-board, so it's not likely that the board would be able to burn it's self up.

Also, it's hard to tell someone to look for something suspicous when they don't know what they're looking for. I was just suggesting basic debugging technuiqes would be more usefull before having the poor guy start taking it apart.

:-)

Well, I'm going to see if I can get Ray at Arcade to look at it. He's in TO, so it's no big deal to ship it.

I mostly want to make sure that it isn't something that was my fault. I don't want to go off to MD Game Sales and proclaim the board as DOA and want an exchange (2 months after buying it) without making sure that it's nothing easily fixable and wasn't caused by me.

And thanks everyone for your input and insight.

[ August 08, 2002: Message edited by: td741 ]</p>

Oh well, I tried.

The video ram 8000 error means usually a voltage spike took out the two fast video RAMs, the CXK5814s, which can also be TMM2018s. Have sockets put on them for the future. L :o ose pins or cartridges do NOt cause this problem. Welp, loose pins on LSPC-A0 *MIGHT*, but its more likely a voltage spike.

Fixable.

I read your past responses to this NT, but I'm glad to hear you confirm it here.

Does the POST stop at the first failure or come up with others afterwards? If it stops on first failure, do you know what other checks are performed after the video ram check? I don't mind getting the board fixed, but I just don't want it get it fixed and find out that something else if fried.

Thanks.

My two cents, lose the 12+ volts, you don't need it.

The POST I forget the exact order, bnut it does test the following:

SPU2 checksum and routines (can come up with a system ROM error, or some wording like that)
slow video RAM error (000000-something)
fast video RAM error (8000-)
color pallette RAM error (forget where)
sound communications (generic Z80 error)

During the green screen for 2 seconds, it is actually testing the clock calendar, and may come up with a Calendar Error at the time.

The self test will stop at any of those and not continue.

Taking out the 12 volts will only gfive no power to the sound circuits and will let the game play normally, just no sound...

Okay thanks.

So in theory, I'm hoping that the ram change will cure the problem but others might be lurking since the POST might stop at a later test.

*Crossing fingers*

As a rule, multiple failures on the MVS are quite rare.

Also, check for a slight bubble on top of the ROM-L0 chip. If a voltage spike is hot and heavy, that chip is next in line. Its not tested, as its only the sprite scaling table. If that rom is bad, then you will get into game mode with text, but no graphics...

Thanks everyone for your input.

[ August 14, 2002: Message edited by: td741 ]</p>