2 slot video ram error

DuffCon

Kuroko's Training Dummy
Joined
May 9, 2015
Posts
71
Gents,

I have a new to me 2 slot board with the following ram error:



address write read
00000c1d 5555 5455

from reading here I believe this is the cxk5814p chips near LSPC-A0. But I wanted to confirm with experts

thank you!
 

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BIG BEAR

SHOCKbox Developer,
20 Year Member
Joined
Dec 14, 2001
Posts
7,669
Gents,

I have a new to me 2 slot board with the following ram error:



address write read
00000c1d 5555 5455

from reading here I believe this is the cxk5814p chips near LSPC-A0. But I wanted to confirm with experts

thank you!
fast ram.
Yeah, that's correct.Make sure there's no broken tracks.I like to install sockets after they go bad.
BB
 

maki

Kabuki Klasher
Joined
Jan 1, 2022
Posts
125
precision socket 24 pin, if you want to go fancy get the gold plated ones, just check the dimensions

the palette RAM is the fastest RAM on the AES, personally I'd avoid sockets with feather contacts for stuff that fast
 

ack

Galford's Armourer
10 Year Member
Joined
Apr 9, 2009
Posts
454
Slow vram range is 0x0000 to 0x7FFF
Fast vram range is 0x8000 to 0x8FFF


Your error points to the upper slow/32k vram chip.

 

DuffCon

Kuroko's Training Dummy
Joined
May 9, 2015
Posts
71
Ok, thank you for the correction. I’ll source one of these chips:

  • CXK58256MM-12
  • KM62256CLG-7
  • W24258S-70LE
  • CXK58257AM-12LX

I appreciate the amount of community and documentation on the MVS platform, makes repairs possible for mortals like me.
 

BIG BEAR

SHOCKbox Developer,
20 Year Member
Joined
Dec 14, 2001
Posts
7,669
Oh crap. Thought that the 0 was an 8 my bad! Good catch.
BB
 

maki

Kabuki Klasher
Joined
Jan 1, 2022
Posts
125
not a pro, but the Neo Geo Dev Wiki states:
  • CXK58256MM-12
  • KM62256CLG-7
  • W24258S-70LE
  • CXK58257AM-12LX
  • any "43256", "62256", CXK58257
I really don't think its picky, any should do
I was lucky enough to not have to buy any so far, using parts from junk boards.

Its some old JEDEC standard, just the timings are different IMO, don't go above 120ns and you should be fine
 

DuffCon

Kuroko's Training Dummy
Joined
May 9, 2015
Posts
71
I’m mostly asking for a good source because the parts numbers I see are off a bit, like the link I posted above.

how about these?


 

DuffCon

Kuroko's Training Dummy
Joined
May 9, 2015
Posts
71
Many thanks for the help! I was able to source a new chip and replace the offender! We saved this PCB!
 

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