Emergency board repairs

[supertakumar]

Bought a few cheap boot boards recently but 3 of them seem to have graphical problems.

It seems a bit strange as the seller said they were all working, so perhaps it's a simple fix. I don't have time to go into a dispute with him at the moment, so i would just like to get them fixed this week in time for an upcoming event.

I've tried them on two or three different machines but no luck so far.

So looking for people based in London who might be able to have a look at them for me?

Thanks.

Here's a couple of pics:

SF2'



Dynablaster

[RMRM]

You are aware that it's a bootleg, right?
Might be harder to repair.

[supertakumar]

Of course, as i said, cheap boots.

If i can't fix them that's cool, i'll send them back, but for now would be good to see if they're repairable as would be nice to have them up and running for the weekend.

[thomj]

I suppose you have metered the voltages already?

[supertakumar]

No i don't have the time or expertise to do that at the moment. Got a lot of other stuff to look at in time for the weekend.

I have a friend who is capable of doing that who will have a look on Tues if i haven't found anyone else by then.

Quick question though...if i've tried it on 3 different cabs and the result is the same, could that still be a voltage issue?

[thomj]

Yes, it could easily be the problem. That first screen is really common as a hang screen when the voltage is off. Normally too low but DON'T JUST BLINDLY TURN IT UP. You really can't get away with not owning a multimeter in this hobby. A cheap made in China job off ebay would be totally fine and it's super simple to use one. I suspect that these boots are just a touch power hungry and probably will work fine once you tweak the 5V.

If you search on here (and probably the wiki) you will find several guides on how to measure the voltages. Do that and I suspect you'll 'repair' them yourself.

[supertakumar]

That's brilliant, thank you so much.

Yeah, i didn't really have any doubts in the seller, i imagined it was either a transit problem or something i was doing wrong. Would be too weird for 3 boards to go like that. I just got a bit stumped when it happened on various different machines.

I do have a multimeter myself, but i want to make sure in this case that i get someone competent to use it. Will check on that Tues eve, and see how it goes.

Thanks again

[rugdoctor]

the board you are showing is missing a capacitor near the jamma edge as well...same specs as the other caps on the board close to the sound section.

[muddymusic]

Dynablaster looks like the h sync needs adjusting on your monitor.

[ninn]

... and the SF2 has its kickharness cut.

[Asayuki]

... and the SF2 has its kickharness cut.

True. Actually those cut wires look soldered directly on the pins instead of using a proper connector...
Anyway they are just for the added buttons; no way they can cause the garbage that is seen on the photo.

I would try to carefully reseat the cpu and its four roms. And while there check that no pin is bent. If that does not help then chances are that the board got broken. Maybe the crystal got shocked during transport. It looks to me like the cpu is not even trying to boot.