MK4 PCB problems- Help!

khabbi

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Just purchased a MK4 PCB, revison 3, and the board appeared to be in mint condition..

Fire it up, and everything check out.. then as I start to play, I notice a slight lag at the end of the screen before it goes to the next round, and a few other ever so slight lags in the video.. then once it got warmed up, it started to reset randomly... then as it stayed on, continuous.

When warmed up, it threw this code on boot up: Wave ram bank 0 error F9

The machine would then loop into a green screen, etc, then to the initial test.. and now it would not show the error... but would reset again to green screen, blue screen, etc.

I turned the machine off and let it sit for 15 minutes.. then it worked fine again until it got warmed up.. then it would randomly reset.

Here's a youtube vid of the screen and the board :

http://www.youtube.com/watch?v=hzQ4C12GecE

board installed in a z-cab that had a different MK4 board in it that worked fine, except that the color red as not present.. was determined to be in the board, the new board showed the red on the screen perfectly. A Ms. Pac man board installed into the cab worked fine (turned sideways though :)

Any ideas how to progress from here? Being new to collecting games, I must say this has been frustrating!

thanks for any help in advance!!
 
Well, I just plugged the old board back in, and that is doing the same thing now. I think I may need a new power supply, does anyone know where I can get one that will match right up? Its an exactron as pictured below.

Also, how would I test the amt of voltage going to the board, from the pics below? Or should I just load the machine up and take it to my repair guy, lol..

I must say, this has been frustrating!! At least before I could play it.. I installed the new board, then everything went crazy!! UGH!!

img2218b.jpg


img2220in.jpg


img2221r.jpg
 
there's a multitude of places to get it. there's always Happ, www.happcontrols.com or the KLOV community's favorite, www.therealbobroberts.net.

either one's got a catch though... non-account holders with Happ have a minimum order to make (so if you need T-mold or buttons or switches or something, might as well get those too) and with Bob he doesn't accept credit or paypal, he only takes checks, and first-time customers have to clear their check before he sends out the goods.

there's the big XT style power supplies that have molex harnessing on them, but for this I'd prefer you go the screw terminal route like your existing power supply. if your cab's wired up for a screw terminal kind, you're gonna be going batshit stripping and splicing wires with the molex variety. :)

Happ has a cross-reference sheet in their catalog, but for the most part I don't think it matters for a regular JAMMA game like MK4 versus say a big goliath like Daytona USA that requires a lot of juice and amperage.

if you have any questions feel free to PM me.

the other option is to peruse the For Sale section on here to see if anyone's got power supplies for sale.
 
Have you tried turning the +5 voltage up on your power supply just a bit? It's the white stick right next to the green light. Just turn it a little bit and it may fix your problem without having to replace the whole power supply.
 
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