CurtPalme.com Home Theater Forum

[dturco]

Before I turn GOZER on I have removed the Focus board entirely, the ribbon cable to the convergence board CVA? is off also. The power cord is a standard IEC correct? I could use the one from my spare computer to power on. The power socket on the LVPS I don't think so, because it did not have a problem at Mike's place.

[Nashou66]

Yes to all, except the plug I mean the outlet at the wall its plugged into. Is the ground there ok? Do you have a three pronged outlet tester? it will let you know if the ground is bad or the polarity is off, that too can cause some issue but not sure to what extent.

Athansios

[dturco]

[J Kildare]

I still say you have a ground issue and would not trust a plug checker.
If you can, I would take an extension cord to the neighbours house and plug in there. Better yet take the projector to the neighbours house. Then try and get it back

Is the seperate circuit running from a sub panel?

Jim

[dturco]

[garyfritz]

[Nashou66]

[dturco]

[Nashou66]

On older sets there is ground cable from the vdm to a scew
on the mother board . It's a white cable.

But if the ribon cable is disconnected the should be no power
to those two boards . So I have a feeling possibly an amp on the
vdm may be arcing to the cva and swa boards . If you can remove
the clips from all amps and look for any shorts to the heat sink.
the clips could be carrying the short throug the clips.

Nashou

[dturco]

White wire is in place. i will remove the clips a look for the arc/ scorch.

Removed all clips, stig board moved freely and easy, deflection board same thing, the convergence board was stuck in place and needed a good amount off force to move it. All boards are now moving freely. Where the were clipped into place there are dark markings but no burn throughs apparent. Both gray strips on the heatsink are intact.

[emdawgz1]

[Nashou66]

ok make sure the VDM ribbon cable is connected and does not have any kinks or worn/split insulation. There has to be an arc/short somewhere on that board I would assume since there is no power from the mother board tot he CVA which in turn feeds the SAB. Turn it on and look closely for where an arc or short occurs. There has to be one somewhere .

Or there is an HV leak that somehow is making its way through the VDM cables to the rear boards sice you removed all the convergence cables and Astig cables and the one ribbon cable, you did remove the convergence cables also correct?

Athanasios

[dturco]

[Nashou66]

yes

Nashou

[dturco]

[Nashou66]

[bbfarmht]

[dturco]

Ok I put back the convergence cables 1 at a time, blue first 3 cycles on off it sparked once. Then I removed the blue and put on the green 3 cycles sparked 2 times. Red same as green. Put all cables on it sparks every time on an doff. Did not do the coil looking yet>

[Nashou66]

So when no cables are connected to the CVA there is no sparking, correct? We need to be able to see if there is any HV leaks/arcs to the CVA connectors. I can't see it being a bad CVA since you saw sparks on it with out the Ribbon cable which feeds it power connected, and there is no other way for power to get to that board with out it. And since the convergence cables were connected when you saw the sparks it would lead me to believe there is power traveling along your convergence cables to the CVA.

Just to be sure its not the CVA reconnect the Ribbon cable but not the convergence yoke cables and see what happens spark wise on those boards.

Athanasios

[Curt Palme]

I thought you were onto something with the arcing, I should have posted earlier, but no, that's normal, here's why:

There's a huge voltage potential beween the inside and outside of the tube, 34,000 volts to be exact (give or take a volt or two. )

When the set powers down, the 34Kb drops to 0, and the coils on the necks of the tubes pick up this discharge in the windings, and a voltage potential is created at the yoke connectors. That's all yoke connectors, convergence, astig, and focus, etc.

So, when you disconnect the convergence ribbon cable, you now effectively disconnect the yokes from the circuit and ground. THe voltage that the yokes pick up have nowhere to discharge to, so they do so through whatever convenient point they can find, and you see that with the arcing as the voltage discharges.

So sorry, that's the wrong path to chase down.

Wanna do something fun, and maybe get a tingle at the same time?

Power down the set, and immediately unplug one of the main H yoke wires at the big white connector. Hold the yoke connector end to the metal casing of the H board housing, and watch the discharge of the main yokes as the HV goes to 0.

Hold the yoke wires well away from the connector.. or it will discharge to the closest ground point... YOU!

[Curt Palme]

I thought you were onto something with the arcing, I should have posted earlier, but no, that's normal, here's why:

There's a huge voltage potential beween the inside and outside of the tube, 34,000 volts to be exact (give or take a volt or two. )

When the set powers down, the 34Kb drops to 0, and the coils on the necks of the tubes pick up this discharge in the windings, and a voltage potential is created at the yoke connectors. That's all yoke connectors, convergence, astig, and focus, etc.

So, when you disconnect the convergence ribbon cable, you now effectively disconnect the yokes from the circuit and ground. THe voltage that the yokes pick up have nowhere to discharge to, so they do so through whatever convenient point they can find, and you see that with the arcing as the voltage discharges.

So sorry, that's the wrong path to chase down.

Wanna do something fun, and maybe get a tingle at the same time?

Power down the set, and immediately unplug one of the main H yoke wires at the big white connector. Hold the yoke connector end to the metal casing of the H board housing, and watch the discharge of the main yokes as the HV goes to 0.

Hold the yoke wires well away from the connector.. or it will discharge to the closest ground point... YOU!