Weird MK3 PCB problem.

[Savannan]

This has happened since I owed the PCB.

When the PCB is cold (haven't been running for a day or so)..when I turn it on..the graphics are all messed up...but when I leave it on..it progressively gets better.  About 30 mins with the PCB turned ON the graphics are fine...but once the PCB gets cold it acts up again....

The only thing I can think of is that there might be a bad solder point, and once it warms up it makes the necessary contact??

Just wondering if anyone has seen this problem before with this game or similar.

Thanks
Sav

PS.  During ROM check all the roms test GREEN

[ctozzi]

could be a bad power supply in the cabinet as well, 90% of all cabinet issues stem from a bad power supply

[Savannan]

Thanks for trying to help out but, I don't think its that.  I have MK1, MK2 and MK4 using the same power supply and they all work FLAWLESSly....

Maybe this Sunday I'll take it to work and use a magnifying glass to see about solder points.   I even took out the roms and re-inserted them ... 

[boardjunkie]

You use freeze spray to localize the problem area.

[MonMotha]

Reseat all the socketed chips, not just the ROMs, while you're at it.  Somewhere, there's probably a bum joint that works when things are warm as stuff expands.

Other possibility is power.  Just because it works on many boards doesn't mean it'll work on them all.  Check that it's right at 5.0V (4.9-5.1).  If still in doubt, just replace the sucker; there are faults that can't easily be diagnosed with a typical meter.  Quality replacements are like $25-35.

I'm not a fan of the freeze spray except as a last resort.  That much thermal shock can easily cause additional problems by cracking joints.

[Savannan]

What is freeze spray and how does it work?

Just currious...

[MonMotha]

It's basically a canned air duster turned upside-down (and you can in fact do just that).  Basically, it's a liquid spray that rapidly evaporates (often before it even hits what you're pointing it at), and, in the process of doing so, gets REALLY cold.  "Freeze spray" is an accurate term; it will easily cause frost.

Spraying stuff with it causes a very rapid change in temperature, which can cause cracks due to uneven thermal contraction.  However, it can also be quite effective in locating problems due to thermal issues like you appear to be having for the same reason.

[AlienInferno]

Dang it!  MonMotha beat me too it by a couple of minutes.   

I'm not sure what the freeze spray would be.  I'm guessing something like the wart freezing remover stuff or maybe even a can of compressed air turned upside down.

Also I'm assuming it works by spraying particular areas/components after everything has been turned on/warmed up to see if you can replicate the problem.  Since everything expands when warm (and your issue goes away) the freeze spray would cause it to shrink back down and cause the issues to reappear as if the machine was cold still.  Might be usefull to pinpoint the damaged areas.

I would let someone more knowledgable to chime in though before trying it as I'm probably 100% wrong.

[mgb]

If you choose to use freeze spray, its available at Radio Shack.

[lilshawn]

... yah, anyway, enough theory...

 what you want to do is get your board warmed up, and running. then, using one of those duster cans turned upside down, spray small bursts at various components until the game fails, freezes, displays garbage, etc... then you have where to start looking.

[Savannan]

I'm heading to work now..Goin to take that PCB with me and remove/label all chips...then see if I can find something obvious.  Just the simple stuff 1st 

My only question about doing that is....Once I get the PCB warmed up and is working properly, I spray the can upside down to freeze a area of the pcb.  Look to see if I see problems...then move onto another section.....all while the PCB is connected and turned on....

but is that freeze spray conductive? should I be worried about it shorting out something?

[lilshawn]

I'm heading to work now..Goin to take that PCB with me and remove/label all chips...then see if I can find something obvious.  Just the simple stuff 1st 

My only question about doing that is....Once I get the PCB warmed up and is working properly, I spray the can upside down to freeze a area of the pcb.  Look to see if I see problems...then move onto another section.....all while the PCB is connected and turned on....

but is that freeze spray conductive? should I be worried about it shorting out something?

Just don't go crazy. You just want to cool it, not freeze it so frost forms. Frost AKA frozen water, when it melts, IS conductive.

But that is the general idea.

[Savannan]

Well I took my PCB to work and I did find a solder point cracked,  re-soldered it, powered it on and same thing.

I think I'll head to Radio Shack today and see if they have that freeze spray.  The game looks/plays great after 30 mins of it being cold, but its kind of a pain.

Sav

**EDIT** Just looked on Radio Shacks web site and no freeze spray.  Is it under another name?

[Malenko]

try it the other way, push on chips while its cold and see if the issue goes away