Results 1 to 23 of 23

Thread: MV2F - Video RAM error - address is all p's

  1. #1
    .
    Join Date
    May 2020
    Location
    Michigan, USA

    Posts
    11

    MV2F - Video RAM error - address is all p's

    Hello all,

    I have a MV2F with a weird video RAM error. Normally I'd replace the VRAM but instead of an address, I have all p's. I've recapped the board and I can't see any bad traces.

    https://i.imgur.com/FuiWkTj.png

    Any ideas on where I should start?

  2. #2
    .
    Join Date
    Jan 2020
    Location
    ruanda

    Posts
    122
    replace vrams to start

  3. #3
    Edo Express Delivery Guy
    ack's Avatar
    Join Date
    Apr 2009
    Location
    Seattle, WA

    Posts
    339
    This is the same thing I replied to you on the other forum you asked this on.

    "It looks like bit 5 of your lower 32k/slow vram is stuck high. This is causing drawing of fix tiles to be wrong if the tile being draw doesn't already have that bit set.

    The actual error would be for address 0000000, write 5555, read 5575"

  4. #4
    .
    Join Date
    May 2020
    Location
    Michigan, USA

    Posts
    11
    Quote Originally Posted by ack View Post
    This is the same thing I replied to you on the other forum you asked this on.
    You're right, thanks! I didn't have notifications turned on over there, thanks my dude.

  5. #5
    .
    Join Date
    May 2020
    Location
    Michigan, USA

    Posts
    11
    Okay so I replaced both VRAM chips as well as the fast VRAM because I had extras on hand. Now I'm getting a bootloop after the BIOS:

    https://photos.app.goo.gl/ScU3511dWFXvXpPV9

    I should note that I've checked the all the ICs and reflowed any shitty looking joints.

  6. #6
    Maxima's Barber
    shadowkn55's Avatar
    Join Date
    Dec 2006
    Location
    SoCal

    Posts
    2,366
    What cartridge are you running? Legit carts show the snk logo up top on the unibios splash screen.

  7. #7
    Edo Express Delivery Guy
    ack's Avatar
    Join Date
    Apr 2009
    Location
    Seattle, WA

    Posts
    339
    Something seems off give the wrong color of the unibios logo. I would try using the diag bios and see what it complains about.

  8. #8
    .
    Join Date
    May 2020
    Location
    Michigan, USA

    Posts
    11
    What cartridge are you running? Legit carts show the snk logo up top on the unibios splash screen.
    Fatal Fury 3

    Something seems off give the wrong color of the unibios logo. I would try using the diag bios and see what it complains about.
    Is there someone around here that sells pre-burned eproms? I don't have a burner. I guess I probably should order one
    Last edited by touche112; 06-02-2020 at 12:38 PM.

  9. #9
    Maxima's Barber
    shadowkn55's Avatar
    Join Date
    Dec 2006
    Location
    SoCal

    Posts
    2,366
    What speed ram did you use for both fast and slow vram?

  10. #10
    Edo Express Delivery Guy
    ack's Avatar
    Join Date
    Apr 2009
    Location
    Seattle, WA

    Posts
    339

  11. #11
    Maxima's Barber
    shadowkn55's Avatar
    Join Date
    Dec 2006
    Location
    SoCal

    Posts
    2,366
    If it is, those rams aren't vram.

  12. #12
    .
    Join Date
    May 2020
    Location
    Michigan, USA

    Posts
    11
    Quote Originally Posted by ack View Post
    Something seems off give the wrong color of the unibios logo. I would try using the diag bios and see what it complains about.
    Found that issue, it was a loose green going to the JAMMA harness. Color is fixed now.

    Quote Originally Posted by ack View Post
    Hahaha no, not the same board. That one was fucked a while ago and I was just messing around with it. Some backstory, I got three MV2Fs from a guy on Craigslist. The one with the fucked up backup RAM was/is a POS already, with a bunch of ICs that were bridged and corrosion everywhere. The one in this thread with the video issues is a different board altogether.

    Quote Originally Posted by shadowkn55 View Post
    What speed ram did you use for both fast and slow vram?
    Fast VRAM is 15ns, slow VRAM is 55ns. Just to make it clear the Reddit post I made was a different board - I did replace the right chips on this one
    Last edited by touche112; 06-03-2020 at 01:07 PM.

  13. #13
    .
    Join Date
    May 2020
    Location
    Michigan, USA

    Posts
    11
    Okay I just tested with a second game I just got in. I get the same address range in my exception error for both carts, which makes me think its not a cart problem: 00C11622

    Slots and carts have been cleaned with Deoxit.

  14. #14
    Maxima's Barber
    shadowkn55's Avatar
    Join Date
    Dec 2006
    Location
    SoCal

    Posts
    2,366
    That address corresponds with the bios.

  15. #15
    .
    Join Date
    May 2020
    Location
    Michigan, USA

    Posts
    11
    Quote Originally Posted by shadowkn55 View Post
    That address corresponds with the bios.
    As in, my Unibios flash is corrupt?

  16. #16
    Maxima's Barber
    shadowkn55's Avatar
    Join Date
    Dec 2006
    Location
    SoCal

    Posts
    2,366
    Quote Originally Posted by touche112 View Post
    As in, my Unibios flash is corrupt?
    Probably not. The unibios has it's own crc check and it will throw a separate error if the chip itself was bad.

  17. #17
    .
    Join Date
    May 2020
    Location
    Michigan, USA

    Posts
    11
    Quote Originally Posted by shadowkn55 View Post
    Probably not. The unibios has it's own crc check and it will throw a separate error if the chip itself was bad.
    Have any suggestions for what to check while I'm waiting on the diag bios?

  18. #18
    Maxima's Barber
    shadowkn55's Avatar
    Join Date
    Dec 2006
    Location
    SoCal

    Posts
    2,366
    Did the original vram error go away when you replaced all the vram chips?

  19. #19
    .
    Join Date
    May 2020
    Location
    Michigan, USA

    Posts
    11
    Quote Originally Posted by shadowkn55 View Post
    Did the original vram error go away when you replaced all the vram chips?
    Yessir.

  20. #20
    Maxima's Barber
    shadowkn55's Avatar
    Join Date
    Dec 2006
    Location
    SoCal

    Posts
    2,366
    Throw all the dip switches down and see if any other errors show up.

  21. #21
    .
    Join Date
    May 2020
    Location
    Michigan, USA

    Posts
    11
    Quote Originally Posted by shadowkn55 View Post
    Throw all the dip switches down and see if any other errors show up.
    Ok well, I did that, and the screen flashed, and then went to nothing. Now it's acting like there's no BIOS chip. I reflowed the BIOS socket and I can't see any damaged traces around the BIOS socket... Same behavior with original chip and Unibios.

  22. #22
    .
    Join Date
    May 2020
    Location
    Michigan, USA

    Posts
    11
    Slight update, it's clicking at least so now I'm re-checking all the RAM

  23. #23
    SHOCKbox Developer
    BIG BEAR's Avatar
    Join Date
    Dec 2001
    Location
    Philadelphia,PA
    Posts
    7,163
    you are going to have to check your traces between the LO chip and your 5814's...it look like somethig is going on with that 531000
    BB
    In case of 'PM BOX FULL ANXIETY' , E-MAIL ME

    bigbearatdreamamusement.net replace "at" with an "@"

    I'd like to sincerely THANK everybody that supported SHOCKbox over the (EST 2001) 8 - 9 years I did it.
    http://www.dreamamusement.net/photos/sth.gif is stocking the SHOCKbox right now!! They also have a huge library of SHOCKbox inserts for DL and or printing.
    LE GEEK SHOCKbox inserts

    I'm not protecting myself from you....I'M PROTECTING YOU FROM ME.
    SKYWAY PRO Keep this a secret!

Thread Information

Users Browsing this Thread

There are currently 1 users browsing this thread. (0 members and 1 guests)

Posting Permissions

  • You may not post new threads
  • You may not post replies
  • You may not post attachments
  • You may not edit your posts
  •