continued monitor sadness (D9200)

[jerryp]

After several full chassis swaps (all boards and cables) including a supposedly new chassis from WG - my D9200 still exhibits the same problem as I started with a few months back.  A pulsing/flickering contrast - all the time - even without any input device. 

All that's left is the tube (I think)!   Anybody have any ideas what might cause this contrast pulsing/flickering problem that persists through multiple chassis swaps.  I don't think there's that much electronics between the tube and the chassis (maybe I'm wrong) but I've had my original chassis 'repaired', swapped in a 'refurbished one', and now a 'brand new' chassis and still have same issue...  I'm at the end of my rope here.

Any suggestions (other than call WG tech support, I think I'm done with that)?

[Ken Layton]

Cabinet/power grounding?

Cabinet power supply good?

Have you tried a different monitor in this cabinet?

Is there a problem in the cabinet wiring harness? Like AC power wires bundled next to video signal wires.

[jerryp]

Thanks Ken... one of my first suspicions was power/grounding (and I haven't totally ruled it out).

This monitor was originally plugged into a 'smart' power strip when it started happening - but some of the things I've tried are:

1) plugging monitor direct into a wall socket independent of cabinet
2) plugging direct into a UPS to isolate the circuit
3) plugging into an extension cord and running out to a different circuit in the house altogether...

So basically, regardless of what type of power input I give it I get the same results out.  At this point I also don't have any video input going to it and I see the issue (contrast pulsing) with the stock "No Input" display that comes up when you have no signal.  This rules out anything but the monitor/power being the issue to me.

I noticed that the main board from my original chassis had a separate nut on the side with a ground connector (and "ground" symbol).  It was never hooked up to anything but the new chassis main board that I have does not even have this ground connector option - the metal base that holds the mainboard in place is wider than the original and the screw holes no longer line up to the original frame that this was in.  Not sure if that's interesting or not but I thought it was worth mentioning, as maybe the ground is an issue.

Any idea if there could be something power/ground-wise and if so how could I verify it?

I have no other full monitors to test with - I've rotated 3 sets of boards through the same frame though so obviously that was not the issue, but I only have one cabinet and one full monitor.

Thanks,
Jerry

[jerryp]

I wanted to add some more info that might trigger someone to offer some suggestions on this.

First a correction, I stated previously that the contrast pulses, when in fact its actually the brightness, not contrast.

Secondly, I can make this go away *completely* if I turn the center knob on the flyback clockwise, *however* the problem becomes that my focus gets blurry to the point of being unusable.  So that is the tradeoff - blurry but stable, or sharp but brightness flickers...

I'm open to any suggestions - but things already done are:

1) cap kit
2) sent chassis into WG for repair
3) brand new chassis
4) isolate power (used UPS, different power circuits)
5) no input to monitor (just plug straight into power outlet, no PC input)

The only thing that remains the same is that I have the original non-chassis parts (basically tube).  Chassis modified and swapped out a couple times with no positive effect.

This problem all started when the cabinet was moved a few feet from its original location (inside the living room in my house) but I can't seem to correlate the cause and effect.

Anyone..?

Thanks,
Jerry

[miles2912]

Did you verify if it was power or not?  You are going to have to take it somewhere else and plug it in to verify.  Maybe a neighbor? 

D-

[jerryp]

I've manged to have some success with one of the chassis sets...  they key is in tweaking the flyback focus knob to the exact point where the problem stops and right before the focus gets blurry.  On my original chassis I could never reach this nirvana but with the new chassis I have been able to get it looking pretty good.  I'm a little hesitant to declare it fixed until I can put some hours in it and verify it.