Backup ram error on a 2 slot mvs please help.

[Ace]

As subject I have a 2 slot mvs motherboard that comes up with error,

Backup Ram Region
Address - 00D00010
WR - 5555
RE - B240

Even using raz's universal bios I am unable to load any games. Now I am pretty sure this due to one of the surface mount rams but which one exactly?. Also I already have some Sony CXK58257 ram's which are surface mount, are these compatible?. Any help is greatly appreciated.

Ace.

 

[channelmaniac]

Yes.

 

[topher]

Try putting all dipswitches in the on position and powering up your board before you replace anything. Sometimes the RAM just gets corrupted.

 

[Ace]

Tried that topher, before I did that all I would get is the green screen that you usually get when you turn a mvs motherboard on but it wouldn't get past it and kept resetting.

channelmaniac: Yes to what?.

 

[channelmaniac]

Also I already have some Sony CXK58257 ram's which are surface mount, are these compatible?
Ace.

Yes to this.

Can you desolder & solder in some surface mount SRAM chips?

 

[Ace]

Yeah that won't be a problem, would help if I knew which was the bad ram though.

 

[Ace]

Ok I replaced the two rams with two known good ones and fixed a trace. Now I get this error message http://www.zen91691.zen.co.uk/mvs/newerror.jpg.

I guess it wasn't the ram so I replaced them for nothing and now have to search for yet more broken traces.

Any suggestions to where the broken trace(s) maybe judging from the error message?.

 

[Ace]

Wow 10 years, I pulled this out to look at it again today. I finally found the broken trace, it was on the top corner near the battery. A trace going from a transistor pin to a pin on the near by 74HC32.

My mistake all those years ago was not using a logic probe, took about 5 minutes to find the broken trace.

 

[CossackWarrior]

Hey Guys, new to this forum. I cant start a thread for some reason yet, so I am hijacking this one........really sorry. Maybe someone can PM me with the technical knowledge I need to fix the issue I have. I have a very nice clean and almost new looking 6-slot pcb that needs a repair. It boots up to a "work ram error" and specifies ADDRESS 00105A80 WRITE 5555 READ 7555

Maybe someone can circle with rams I need to change. Pictures below:

 

[CossackWarrior]

Anyone........

 

[nanash1]

I'm no expert, but according to this page: http://www.arcadecomponents.com/repairlogs.html#88601 your upper work ram is faulty and located at J9. Follow the letters and numbers at the edge of the board to find it.

 

[CossackWarrior]

Sweet, that is perfect. I shall change that ram, and and re-test again. Crossing my fingers Thanks.