Odd TriSync Monitor Behaviour: Display shift in VGA mode (31K)

[lowlight]

Hey everybody,

This is an intermittent annoyance that I've noticed for a while now (couple of years) with my AtomisWave SD Cabinet's stock TriSync monitor. I'm curious to know if anyone else here has had this happen before, what causes it, and if there is a permanent fix-action for this behaviour.

Occasionally, for what seems to be no discernable reason, the monitor's display will completely shift to the left-hand side by about 1/3 of the entire display. This ONLY ever happens when a direct VGA game is hooked into the cabinet (Sega Naomi, Sammy AW, etc). This behaviour to date has never happened with standard or medium resolution games hooked into the cabinet. What's confusing about the display shift is that it seems to happen randomly; I can't seem to replicate the problem on a consistent basis. What's more, is that it will every so often come/go after long periods of idle uptime (days to weeks), and when it does occur can last from a few minutes up to a day or so until it seems to go away on its own.

Sometimes this odd shift of the screen can be "cleared" by manually unplugging the monitor from the cabinet's internal outlet, waiting for 5-10 seconds (a completely arbitrary time), and then plugging it back in. At first I thought it might be some odd form of EMI in the cabinet or the other surrounding arcade equipment, but the occurrence of the shift doesn't change regardless of where I relocate the VGA cable run within the cabinet. Additionally, I ruled out the additional SUN Power supply as the contributor (Sega Naomi), as this problem occured when I was still using the cabinet's in-built JVS harness.

Any ideas/suggestion/solutions are welcome. As I mentioned in the beginning, this is more of a mild annoyance than anything, and I really want to know more about why it happens than anything else, as I've never seen it before in any of my other VGA arcade equipment (Crazy Taxi Sit Down, Gauntlet Dark Legacy, etc).

 

[PascalP]

What chassis is in your AWSD?
The stock Wie-Ya C3129D? I would point my finger towards that piece of Chinese excellence as the culprit, no offense...

I know @Sp33dFr34k had some issues with image shifting as well which where fixed by unplugging the VGA and plugging it back in with his Taito Type X2, but we didn't find a fix as it stopped doing this at some point...

 

[lowlight]

What chassis is in your AWSD?
The stock Wie-Ya C3129D? I would point my finger towards that piece of Chinese excellence as the culprit, no offense...

None taken whatsoever; I'm always learning something new! Yes, that would be the right chassis on the rig (same maker goes for the Power supply to the cab itself). As for plugging and unplugging the actual VGA terminal from the end equipment while the cab is still powered on, there was a brief period where I tried to do that (Sammy AW, in particular), but that seemed to cause more shifting problems than solve them.

Interestingly, and perhaps this is common knowledge to everyone else here, but mucking about with the I/O for independently powered equipment (Sega Naomi, Ultracade, etc) results in unwanted behaviour for probably very obvious reasons. Any type of system sync/timing is lost when I/O communication is interrupted. So, simply toggling on/off the power switch on the cab with independently powered equipment, in my experience, is just as bad (if not worse, maybe) for this problem.

At least it's good to know it has a strong possible link back to a FRU that can at least be replaced. On that point, what other chassis are compatible with NANAO monitors of this type (assuming that's the cause of the problem)?

 

[vaughan14]

I have the same chassis and the picture is beautiful , I have never seen the problem you're talking about the only time the picture moves is if i touch the adjustments board is yours secure?

I'm about to get another one too but the flat screen version.

I just had mine serviced from a guy in Australia, he only deals with Australians though.

http://wiki.arcadeotaku.com/w/Rodotron_666

That page has some good info, maybe shoot that guy an email from jomac.

 

[lowlight]

I have the same chassis and the picture is beautiful , I have never seen the problem you're talking about the only time the picture moves is if i touch the adjustments board is yours secure?

I'm about to get another one too but the flat screen version.

I just had mine serviced from a guy in Australia, he only deals with Australians though.

http://wiki.arcadeotaku.com/w/Rodotron_666

That page has some good info, maybe shoot that guy an email from jomac.

Hrmm...I don't understand what you mean by "secure", as I would presume I'd have issues on the other resolution bands (Low and Medium) as well, which I do not. Could you clarify that question, please?

Additionally, I never said that my monitor's picture, irrespective of this phenomenon happening, isn't lovely as well, it is. To be clear, this only happens when going into 31Khz and very rarely at that (maybe once or twice a month on its own). Since this is a "monitor" related sub-forum, I thought I would punt the question here to see how common (or uncommon) the issue is with this cabinet/chassis.

 

[gunblade]

there is a small daughter board behind the flyback with 31khz horizontal hold pot-if this pot is on the edge of adjustment then that would give you the results you are seeing

 

[lowlight]

there is a small daughter board behind the flyback with 31khz horizontal hold pot-if this pot is on the edge of adjustment then that would give you the results you are seeing

Fascinating! I'll see if I can check the current status of this board this weekend; thanks for the insight on this!