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MIPS 06-22-2017 11:47 PM

Nec PX-42VM5A Dead from Standby
I picked this panel up in early February from a local recycler. It worked there. It worked when I got it home. It worked when I built the HTPC for it and it ran fine for the two months I used it on and off. It was flawless.

For April, May and most of June though as things warmed up outside I've been so busy that I have not used it for anything. Tonight I finally had a chance to sit down and watch a movie while the freezing from some dental work wore off.
Turn it on from the remote, LED goes from RED to GREEN and you get the relay click. The screen briefly flickers so the high voltage comes up.
Then after about three seconds the relay clicks again, the green light goes out for about three seconds and then comes back but audibly there is no high voltage. No other indications of a fault. Not even a blinking LED. It's as if the display drivers have shutdown but the digital portion isn't aware of it.
I have left the TV in standby all this time and there was at least two power interruptions in the meantime but I have not found anything in the house that was damaged by those. I have already tried the google suggestions to unplug all the inputs and outputs to no avail and also completely unplugged the set for ten minutes but again with no luck. Its as if it died just sitting there on my bookshelf.
I would blame a capacitor or three somewhere if it saw more use but its just so odd to see a TV die like this.

Electronic M 06-23-2017 10:48 AM

I've had caps die from months standby in VCRs...I've also had LCD sets where a cap died and it would get half way through displayin the startup animation and fall flat on their face and not boot again till an extended unplug....

Caps can be spooky in that they can be j-u-s-t mediocre enough to sorta work a bit, and come back to life under odd say plugging it in after a week or three.

MIPS 06-23-2017 03:21 PM

I'm gonna lean towards that as well.
At work I unearthed another NEC panel of the same make and model (we use them a lot...or we used to) that came in for recycling and behold, exact same fault. The good news is that I got a second machine I can salvage a power supply and driver boards from, assuming it is only a capacitor swap that is needed.

Eric H 06-23-2017 07:36 PM

The power supply in these sets is running all the time whether it's on or not.

I fixed a 32" 2007 Samsung back in 2011 by replacing one swollen cap in the PS, it's still working.

When it's off I can hear the PS singing (it's mounted at ear level), it sounds a bit like the Flyback whine in a CRT set.

MIPS 06-27-2017 08:31 PM

Salvaged the power supply, driver and digital boards from a machine at the office. The salvaged power supply clearly had three failed capacitors so I knew where to check first on mine.
As it turns out like with previous flat panels I've had to work on I have a different revision display because the driver board interfaces with the panel differently, so if that is the problem I'll have to wait for another panel to surface.

I also found that my power supply was in better condition than the salvaged one, so for now I cannot make any better assumptions as to where the fault may lie until I recap at least one of the power supplies.

Also, what is this madness? This is an NEC product but the plasma panel and the power supply are clearly branded by Pioneer.

MIPS 06-21-2018 08:35 PM

Another panel with an identical interior chassis finally surfaced that I was able to verify was fully functional aside from extremely bad burn-in.
Replacing the sustain and the power supply (it probably wasn't the problem but at least I knew this one worked) got me up and going again, though before I put it immediately back into use I will recap the boards as to not have this happen immediately again. :scratch2:

mr_rye89 06-21-2018 11:46 PM

I had a Vizio plasma that I sold a friend do the exact same thing. Replacing the bulgy 'lytics in the PSU fix'd her right up.:thmbsp:

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