Final Fight Graphics Problem

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    • Final Fight Graphics Problem

      Greetings All!

      So, I keep getting a bit over my head with this, but I figure more practice only helps. So, I picked up a final fight board that has a serious graphics problem (I'll post a pic here soon). Upon booting up, the screen is literally covered in a wall of dollar signs ($$$$$$$)? The board sounds great, so no issues with sound. I can send pics of the board itself if needed. I've been reading up a bit and sounds like my next steps are plugging the b and c boards into a known working a board. Just wanted to reach out to see if anyone has seen or heard of any problems like this on other CPS1 boards.

      Thank you so much for your help!
    • Report2Marty wrote:

      Greetings All!

      So, I keep getting a bit over my head with this, but I figure more practice only helps. So, I picked up a final fight board that has a serious graphics problem (I'll post a pic here soon). Upon booting up, the screen is literally covered in a wall of dollar signs ($$$$$$$)? The board sounds great, so no issues with sound. I can send pics of the board itself if needed. I've been reading up a bit and sounds like my next steps are plugging the b and c boards into a known working a board. Just wanted to reach out to see if anyone has seen or heard of any problems like this on other CPS1 boards.

      Thank you so much for your help!
      Here's a pic of it!
      Images
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      • IMG_6417.JPG

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    • Yep, definitely a good idea to swap the A board with a known good one to see if anything changes.

      Other things you can try:

      1) Feel each of the chips on the B and C board with the power plugged in. If any of them are burning hot to the touch, then that chip has probably failed. I've seen this myself with the PAL chips on CPS boards. Also make sure that none of the PAL chips on the B & C boards are missing.

      2) Remove and reinsert each chip on the B board into its socket.

      3) if you have access to another known good B board, swap the ROM chips over to the other B board and try it.

      4) If you have access to an EPROM programmer, read out the contents of each B board ROM chip and check the checksum of the contents against MAME.

      5) Carefully examine the traces on the bottom of each board. Look for corrosion or a broken trace.
    • Also check the pins of connectors when you separate the A, B and C pcbs. Look for bent pins. However, this is a "major" graphics issue, I highly suspect you may have a wrong C board or missing/wrong/malfunctioning PAL on B board. Identify the C board type and read the number on the custom IC on the C board (it'll be on the bottom as far as I remember)

      OR

      A totally busted ASIC on A board. That is easy to identify if you swap it with another one if you have a known working spare.
    • B board PAL failure or missing causes the screen to be broken into 1cm blocks usually, the fact that it's the same thing repeated all over the screen seems like it could be a stuck output? Could potentially be a RAM fault on the A board, A board ASIC failure or definitely possible it's a C board fault.

      Could be a bad trace or connection between the board stack too.
      Namco Cyber Lead and Sega Astro City owner
      My VAPS Profile
    • Ok! So, tested the b and c boards on a known working a board, and no more $$$$'s. There is a remaining little glitch, which takes the form of some vertical stripes, but definitely better than the $$$'s. Guess the next step is to replace some of the ram on the malfunctioning a board, yes?

      Thank you so much for your help and guidance!
    • Cool! I'll check into that! Any chance anyone has the schematic for a CPS 1 A Board?

      Also, and I apologize for my lack of knowledge here, I have an oscilloscope I picked up cheap at a university sale for $20. Is there a good tutorial anywhere? I believe I need the schematic to know how to properly diagnose the signals provided by the oscilloscope, correct?
    • Report2Marty wrote:

      Cool! I'll check into that! Any chance anyone has the schematic for a CPS 1 A Board?

      Also, and I apologize for my lack of knowledge here, I have an oscilloscope I picked up cheap at a university sale for $20. Is there a good tutorial anywhere? I believe I need the schematic to know how to properly diagnose the signals provided by the oscilloscope, correct?
      Schematics are available, just do a google search. Be aware there are two significantly different revisions of the a-board though, the short (lots of SMD stuff) and the long (lots of through-hole parts). IIRC the schematic available is for one revision, but is an update of the old revision so has notes on each on it.

      As usual, I'm going to point the finger at the custom PPU chip - stupid bloody thing.
    • Schematics for both the old-style (rectangular) and new-style (square) CPS1 A boards are here:
      jammarcade.net/schematics/

      The oscilloscope will show you how a signal is pulsing - an active line will pulse low and high, a floating line has no reading and a stuck line will constantly show high or low. You'll use the schematic to determine how the line is supposed to be behaving. There's an excellent thread that goes over arcade PCB troubleshooting in general here:
      forums.arcade-museum.com/showthread.php?t=177192

      My advice: given that CPS1 boards are fairly easy to come by, combined with the high likelihood that your custom PPU has failed, you'd probably save a lot of time and energy on troubleshooting by just picking up a another CPS game instead (like Street Fighter 2 World Warrior) and using its A board on your Final Fight. You should be able to land a SF2WW for under $100. Still doesn't hurt to troubleshoot it anyway if you want to learn.
    • ShootTheCore wrote:

      Schematics for both the old-style (rectangular) and new-style (square) CPS1 A boards are here:
      jammarcade.net/schematics/

      The oscilloscope will show you how a signal is pulsing - an active line will pulse low and high, a floating line has no reading and a stuck line will constantly show high or low. You'll use the schematic to determine how the line is supposed to be behaving. There's an excellent thread that goes over arcade PCB troubleshooting in general here:
      forums.arcade-museum.com/showthread.php?t=177192

      My advice: given that CPS1 boards are fairly easy to come by, combined with the high likelihood that your custom PPU has failed, you'd probably save a lot of time and energy on troubleshooting by just picking up a another CPS game instead (like Street Fighter 2 World Warrior) and using its A board on your Final Fight. You should be able to land a SF2WW for under $100. Still doesn't hurt to troubleshoot it anyway if you want to learn.
      Got a SF II WW board for pretty cheap! Tested the FF board, and still getting the vertical lines. I put the FF board in test mode to see of the ROMs were checking ok, and they are. So, do you think the problem is with the custom chip on the c-board? Is reflowing the legs a possible solution?
    • OK, so your a-board was on the fritz, but you still have another issue.

      Vertical lines can be from:

      *Bad EPROM (or mask rom, depending on your b-board)
      *Trace broken on board
      *Bad c-board PPU
      *Bad connection between a and b boards

      I believe you said you don't have access to a known working c-board? Final Fight and Varth share the same board (for at least some revision, anyway). If you can't rule the c-board out, I'd suggest checking the EPROM/mask roms (you're going to want a programmer, eprom eraser, and some spare eproms anyway to fix any of this stuff).
    • fluxcore wrote:

      OK, so your a-board was on the fritz, but you still have another issue.

      Vertical lines can be from:

      *Bad EPROM (or mask rom, depending on your b-board)
      *Trace broken on board
      *Bad c-board PPU
      *Bad connection between a and b boards

      I believe you said you don't have access to a known working c-board? Final Fight and Varth share the same board (for at least some revision, anyway). If you can't rule the c-board out, I'd suggest checking the EPROM/mask roms (you're going to want a programmer, eprom eraser, and some spare eproms anyway to fix any of this stuff).
      Cool! Got most of that stuff on hand. Any chance you have a link to info regarding what roms handle graphics? I keep reading conflicting info during my google searches :(