Troubleshooting Crime Fighters Board with Sound and Sprite Issues

fleetwood472

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Troubleshooting Crime Fighters Board with Sound and Sprite Issues

Hey guys,

I picked up a Crime Fighters board as is a while back and now that I have gotten around to testing it I have found some issues with it. There are both graphics and sound problems with it. When I turn the machine on there is a high pitch static sound the whole time the game is running. There is no sound or sound effects. There is also a graphics problem. When the game boots up the name crime fighters is basically all blocks or verticle lines. During game play the characters also display as blocks. I ran a self test on the game and at the first self test screen it is just full of blocks. When I skip to the ROM test screen it only tests 2 roms and they both display as bad. These are the ROMS that are failing: 821K04, and 821K05. In the sound menu some of the sounds work. I have attached some pictures showing the issue. I have removed and reseated both socketed chips and have also cleaned them before putting them back in but this does not resolve the issue. I am thinking about getting in touch with hobbyroms to see if they have replacements for ROMS 821K04 and 821K05. Anybody have thoughts or ideas on this? Or any advice on any other possible issues? I'm assuming that these roms have the character sprites in them but would that also affect the sound? Thanks - Justin
 

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The first 3 pics look like there is an issue with the clock to the ram chips. That would cause the issues with the missing vertical lines like that and I would get that going first. Then I would bet that some of the sounds may work.

In this pic of that board I would look at the crystals and it can be a marginal z80 cpu chip (right next to the Crime Fighters chip). Some of the sound is processed by the ym2151 chip right below the Crime Fighters chip pictured.

be very careful of the thin black tall chips the sip (single inline package). They are fairly frail. Many times sound problem are just bad caps and if you can test them do so or just replace them as they don't usually cost much.

http://www.ebay.com/itm/ws/eBayISAPI.dll?ViewItem&item=110954231875&item=110954231875
 
Thanks for the info. Can that also cause the ROMS to false register as bad? I just did the sound check on it in the test menu and everything works for the sound test. It just does not work in the game. I spoke with Hobbyroms and they have replacement roms. I just want to make sure these roms are actually bad. Could bad RAM chips cause them to register as false? I would like to bring this board back to life but also don't want to get too deep into it either. Hopefully this board isn't too badly damaged. Let me know what you think.
 
Thanks for the info. Can that also cause the ROMS to false register as bad? I just did the sound check on it in the test menu and everything works for the sound test. It just does not work in the game. I spoke with Hobbyroms and they have replacement roms. I just want to make sure these roms are actually bad. Could bad RAM chips cause them to register as false? I would like to bring this board back to life but also don't want to get too deep into it either. Hopefully this board isn't too badly damaged. Let me know what you think.

It is very difficult to get a board working epically if you don't know that the program is good and correct. The roms should be verified and if you don't have a way to do that then I would get a replacement set.

Once you get a working set of roms then you can tackle other problems with that board. If there are proms on that board get them also from steph (Hobbyroms) be sure to let him know you are having issues with sound so he will include the proper chips. I would hate for you to get the roms and then have to order proms at a latter date.

Bad ram or even good ram with incorrect speeds can do all kinds of things.

It sounds to me like you just want to get this board working and don't really want to get into the pcb repair too much. If this is the case then get the roms and proms and we can go from there. I suspect the issue will still be there but that is just a guess and you really need a working program before you start to fix hardware.
 
Thanks. Good point I will order both the roms and proms. I looked at the board some more and found some scratches on the back of the board. Looks like there may be some possible damaged traces. I have a friend that has a lot of experience repairing circuit boards so I will have him take a look and see if he can repair the traces. I'll then see if that resolves anything and will report back to you guys on the results. I'll also order the roms and proms after the traces have been repaired. I've taken some pictures of the baord. Do these scratches look pretty bad? The traces don't look broken but i'm sure they are very fragile and some of these scratches have caused some damage i'm sure. Let me know what you think.
 

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They don't look too bad but the ones in the 2nd pic could be a problem. You can't go by looks and they need to be metered.

I hope to help you get this board working.
 
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