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PascalP

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Really, out of all things that can happen when you want to test your MVS Multi...

Board is a MV-1FT which should be similar to a FS.

Any leads on which chip might be bad?

gxhom3O.jpg
 
Jeeezzz.. the devil's taunting us :D
 
The first bank of color RAM is bad - the write/read test has come back mismatched

5555 - expected
DD - RAM bank 0
55- RAM bank 1

Color RAM is a pair of 6264 SRAM, generally Toshiba or Sony slimline in my experience. The bad one IIRC will be the bottom one, not sure where it is on your board but I seem to remember it's usually down near the edge connector

It could also be the associated custom, but I've had colour RAM faults on 3 boards now and on all 3 (all of which had Sony slimline RAM) it was the RAM itself. All Bank 0 too IIRC

Generally the screen goes all 1 colour when these fail too, yours so far just has the big red line at the top
 
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Yeah you tend to get lucky and only need to replace some RAM or mend some rotted traces on MVS. MV1C has a tendency to have bad customs tho. :(
 
The only rotted traces I've ever had are battery damage related, in general I've found MVS boards to be pretty well made.

Just those colour RAMs always die, or the other one I've seen a few times is the Z80, again not a terribly difficult replacement

I've got a 4 slot I attempted to repair but I've pretty much given up on it now which has had battery damage (24 damaged traces all repaired but still won't boot past crosshatch), color RAM replaced, calendar crystal replaced and still doesn't work :P

Which custom dies on the 1C? I have a dead 1 slot 1F and a 4 slot I can harvest the custom from if it helps
 
thanks guys, did check my board and these should be it, will place sockets for both and order 2 new RAMS to be sure.

marking on the chips is Sony CXK5864BSP-12L, which chips would be compatible?
I bought this board a long time ago and this was the first time I tested it, also need to remove the coin button, button 4 wires and replace the battery.
Funny note though by the previous owner that he tested the board as 'good' :(

IMG_2440.jpg

IMG_2441.jpg
 
Unfortunately with old hardware it can be fine one day then dead the next for no apparent reason - just the nature of the hobby :(

Fortunately it's not a difficult fix (hopefully) - you need to use a multimeter to verify the traces coming off the RAM to make sure they're good as that could also be causing the problem - but I believe it's the RAM itself

Cross reference list for that type of SRAM:

http://www.citylan.it/wiki/index.php/SRAM_8k_x_8

Keep in mind not all manufacturers made the slimline type. Toshiba and Sony are the most common but I believe you can get Fujitsu, Cypress and maybe a couple of others
 
I've generally not had the issue of fakes out of China for logic and RAM, more that they arrive and they're also dead. The thing that gets faked is typically they will sell a lower rated part but silkscreen a higher number on it. In saying that their seller rating is good, it's certainly not "new" as it's advertised though, especially at that price.

For the price I'd say go for it.
 
Sounds like a good plan, you can use my desoldering station to get them out quickly and properly, then definitely get them socketed just in case :)

Curious to see if it will boot tonight with the unibios from my MVS board.
 
definitely gonna use you 474+ station :)

yup, I will take my MVS board + multi cart with me tonight so we can try it with your unibios!
 
UniBIOS will boot straight to crosshatch, as it does with errors, then you can bring up the menu and it'll tell you the fault :P

A good desoldering station will have you done in no time
 
Please, don't use Sony RAMs again, they are prone to failure.Choose another brand.
 
Please, don't use Sony RAMs again, they are prone to failure.Choose another brand.
any particular brands/types you recommend?

Can easily swap them around once I have the sockets installed :)
 
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Please, don't use Sony RAMs again, they are prone to failure.Choose another brand.
Please, don't use Sony RAMs again, they are prone to failure.Choose another brand.
any particular brands/types you recommend?
Can easily swap them around once I have the sockets installed :)
Toshiba are just as bad in my experience. I replaced mine with Fujitsu, their logic ICs are generally terrible but RAM is the opposite
 
So after testing with @Sp33dFr34k;s Unibios 3.1, this is the result, everything plays fine except from the colors :)

Waiting for my IC sockets to arrive now...

IMG_2447.jpg

IMG_2455.jpg

IMG_2456.jpg
 
Yep, color RAM is shot, good that it's confirmed now and you can replace it :)
 
Instead of waiting for my parts from China I want to source them locally if possible.
Google didn't give me much...

@Asure would you know where to get these in the Netherlands?
 
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