Need cap value from Midway Wolf unit (NBA Hangtime, MK3, etc)

shess

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Need cap value from Midway Wolf unit (NBA Hangtime, MK3, etc)

I've got an NBA Hangtime that had some physical damage to it. I resoldered one of the ram chips but I just noticed that a capacitor was also knocked off because I can see where the solder points look broken. The cap is C194 as seen in the link. If anyone has this type of board and can tell me what value the cap is, I'd appreciate it.

http://www.flickr.com/photos/7205976@N06/6128613049/sizes/l/in/photostream/

The problem I'm having and maybe it's unrelated to the cap, is that when I boot up the board, it will go through the diagnostics, fail one back of ROMs and then go to a black screen. At that point I can actually coin it up, hit start, and it will play blind. I know the monitor is fine because it works with other games. I wouldn't have thought a small capacitor could do that but who knows. Can I just bridge the solder points as a temporary fix to see if I get the picture back?

Incidentally, the rom banks that fail are the ones attached to the ram chip that I had to resolder back on. I did make sure that I had continuity between every pin though.

Scott
 
Check where the points are connected with buzzer?, if they are gnd and 5 volt, installing a new capacitor will no modify your problem, but if not, you will need to place a new cap to test if this solve the blind issue. The problem is, usually that Caps don´t have the value printed in it, so you have 2 options, 1- Get the circuit diagram or 2- Ask somebody to remove it and measure the value with capacitance meter.
 
Yea, the cap goes to +5 and GND. So I guess it just smooths out the +5V line? It's probably not a coincidence that the ROM bank that shows up red is attached to the RAM chip that got knocked off and resoldered. I checked continuity and it was ok, maybe I should break out the logic probe. I've been unable to find a schematic for this game or any of the Midway Wolf games.
 
I would test and see carefully with a magnifier for any broken trace in pcb, as that is what commonly happens when pcb has been exposed to physical damage. Check specially if data lines of the RAM you resoldered goes to any Custom and compare if you have the chance with other working pcb. Hope you can solve it, regards
 
I would also try putting pressure on the top of that "5410-12862-00" chip and seeing if things show back up on the screen properly.

It's a DMA controller chip and if there are soldering problems with the pins you'll get graphic corruption issues.
 
Thanks I'll give that a try. The chip that was knocked off and resoldered was U29, right next to the big chip. I want to try using my logic probe, but I'm afraid I'll bridge two lines together because they're so small.
 
Well I pressed on that chip that I resoldered and the video started to come back. So it looks like I need to get back on it with the soldering iron. Hopefully this board can be saved!
 
I would also try putting pressure on the top of that "5410-12862-00" chip and seeing if things show back up on the screen properly.

It's a DMA controller chip and if there are soldering problems with the pins you'll get graphic corruption issues.



any sources for one of those DMA chips? :) I'd like one for a revolution x board......
 
it's the Williams Custom Chip. from T-unit (NBA Jam, Mortal Kombat 2) onward it was changed to a surface mounted part, and I'm fairly certain they're all the exact same.

you're local to me, I have a Revolution X board at work that's dead you could probably scavenge that part off of.
 
it's the Williams Custom Chip. from T-unit (NBA Jam, Mortal Kombat 2) onward it was changed to a surface mounted part, and I'm fairly certain they're all the exact same.

you're local to me, I have a Revolution X board at work that's dead you could probably scavenge that part off of.

That'd be great! Can I just paypal ya some money to send it to me? I'm almost never East of Randall.
 
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