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Repair cps1

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ramosribeiro2000

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bought a cps1 on ebay. the roms were corrupted. I changed them and the game still has flaws in the image. testing the problem boards and the motherboard b. does anyone have any idea how to fix it?
 

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board A is working. board C is working. roms set working. the problem is on board B. does anyone have any solution?
 

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It can be a few things, but I'm confused... The B board on the eBay listing is different from the one you used. Did you change the B board?
How did you test the A and C boards?
 
ic3b4ll said:
It can be a few things, but I'm confused... The B board on the eBay listing is different from the one you used. Did you change the B board?
How did you test the A and C boards?
Click to expand...
I did it as follows: the xps1 I bought on ebay was xom graphical problems. then I took the board b from another cps1 that I have working and replaced it on the board I bought on ebay. then the game worked. finally i did the test with the roms replacing them on the board b. the roms are also having a problem. that is, after doing all the tests I saw that the problem is only on the b board, I believe that the roms with problems were swapped. my question is? what problem can board b have?
 
Check underneath the B board and look for broken traces around the graphics ROMs on the lefthand side. Also check inside the pin connectors between the B board to the other boards and make sure that none of the pins are bent or damaged.

You can also use a logic probe to test each pin on each ROM on the B board to look for unresponsive lines. I made a tutorial video for using the logic probe to test ROM lines that you may find helpful:
View: https://www.youtube.com/watch?v=2PAtTIAijeA&t=517s
 
What @ShootTheCore said. I'm guessing it's a bad socket on the B board.

The ROM types are different between the two B boards, despite having 40 pins and being 4 megabit.
If you tested the ROMs by swapping them between boards it will seem they are bad when they are not. They just have different pinouts.
 
ic3b4ll said:
What @ShootTheCore said. I'm guessing it's a bad socket on the B board.

The ROM types are different between the two B boards, despite having 40 pins and being 4 megabit.
If you tested the ROMs by swapping them between boards it will seem they are bad when they are not. They just have different pinouts.
Click to expand...
do not understand. explain better to me. the pinout of both roms is 40 pins. the recorded set works and the original set does not work. explain to me why they might be working
 
ShootTheCore said:
Check underneath the B board and look for broken traces around the graphics ROMs on the lefthand side. Also check inside the pin connectors between the B board to the other boards and make sure that none of the pins are bent or damaged.

You can also use a logic probe to test each pin on each ROM on the B board to look for unresponsive lines. I made a tutorial video for using the logic probe to test ROM lines that you may find helpful:
View: https://www.youtube.com/watch?v=2PAtTIAijeA&t=517s
Click to expand...
I've done it all. u check again. could it not be some problematic component? like ci or capacitors?
 
ShootTheCore said:
You can also try programming a new GAL chip for the socket in the upper-left corner of the B board - it's unique per game, so if the B board is now running a different game than it was before then that could be your culprit.

The list of game files for the B Board PAL are here:
http://wiki.pldarchive.co.uk/index.php?title=CAPCOM_CPS1
Click to expand...
changed all roms. and the same game, street fighter Champion Edition. so that can't be the problem
 
Your B Board is a "MASK ROM TYPE" in the picture, so make sure you're using these types of EPROMs:

27C400 x 12 for the graphics - sockets 1 through 8 and 10 through 13
27C4096 x 3 for the program - sockets 21 through 23
27C010 x 2 for the audio samples - sockets 18 & 19
27C512 x 1 for the audio program - socket 9

If the graphics show up, but partly scrambled, swap around ROM 2 & 3, and 6 & 7.
 
ShootTheCore said:
Your B Board is a "MASK ROM TYPE" in the picture, so make sure you're using these types of EPROMs:

27C400 x 12 for the graphics - sockets 1 through 8 and 10 through 13
27C4096 x 3 for the program - sockets 21 through 23
27C010 x 2 for the audio samples - sockets 18 & 19
27C512 x 1 for the audio program - socket 9

If the graphics show up, but partly scrambled, swap around ROM 2 & 3, and 6 & 7.
Click to expand...
I put the original roms in the frame and the image looks like this
 

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Can you dump the original ROMs and compare their checksums against MAME?

From what I'm seeing in your screenshots, I still suspect one of the PAL chips has gone bad.
 
ShootTheCore said:
Can you dump the original ROMs and compare their checksums against MAME?

From what I'm seeing in your screenshots, I still suspect one of the PAL chips has gone bad.
Click to expand...
can i use the pal chips on this card?
 

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