NEC 42" Plasma shuts off with input signal, stays on without


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NEC 42" Plasma shuts off with input signal, stays on without

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ejm91206
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Oct 25, 2006, 4:30 AM

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NEC 42" Plasma shuts off with input signal, stays on without	Can't Post

My NEC 42VP4 series plasma tv is on the fritz- started shutting itself off yesterday intermittently.
Was ok for a few hours then last night started showing strange coloration, like a reddish tone to the screen. Then it shut down again. Next it showed a dimming screen, gray to black, and shut off. This morning it won't stay on at all. I did discover if I remove any input signal, it will stay on, or if I switch input source to something not hooked up it will stay on. Add input- bam, it shuts off.

Thanks for any help/suggestions.

Ed

(This post was edited by ejm91206 on Oct 25, 2006, 4:33 AM)

denonjapan
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Oct 29, 2006, 3:17 PM

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Re: [ejm91206] NEC 42" Plasma shuts off with input signal, stays on without [In reply to]	Can't Post

It may work for a while now but it's GRADUAL end of it!...One day! when it exibits a quick sparks as you turned on, and displays nothing but dark is when it's officially dead......There's no cure for this! it's assymptomatic effect of any displays. some will reach longer than the predicted life but if yours experiencing this early and the way you explained the dimming, gray to black and shuts of is the obvious electronical problem from the beginning....There is a chance however, it could be your video cards ( inputs you're using) may need re-soldering. Im not sure if NEC 42VP4 equipped with removable slot or permanent. if it won't work either way! don't pursue any further. get another one from matsushita (panasonic) this time!
denonjapan
made in japan

ejm91206
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Oct 29, 2006, 3:26 PM

Post #3 of 17 (6678 views)
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Re: [denonjapan] NEC 42" Plasma shuts off with input signal, stays on without [In reply to]	Can't Post

that's reassuring. NOT.
There is no spark when it turns on. It will stay on indefinitely without any input signals. As soon as the input signal is sent it shuts down without any spark.
The green light turns to solid red.
Is there a diagnostic mode on this thing I can access?

Thanks for your reply(ies).

Ed

denonjapan
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Oct 30, 2006, 2:42 AM

Post #4 of 17 (6673 views)
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Re: [ejm91206] NEC 42" Plasma shuts off with input signal, stays on without [In reply to]	Can't Post

The accurate method to diagnose is if it would be done by OSCILOSCOPE!, NEC service center abroad may not even have it cause it cost 20 plasma displays to have those machine. who would risk to repair a plasma in order to loose more money? NOBODY! know what Im saying?......No manufacturers suggest to take back and repair any problem. (Warranty can be applied redeemable for exchange only. within the given period and that is 90 days the most.)
The symtoms you told, I would definitely fault the video card ( component or DVI?) Nothing else! Try what I told you! what you got to loose?

denonjapan
made in japan

(This post was edited by denonjapan on Nov 4, 2006, 3:15 PM)

ejm91206
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Oct 30, 2006, 2:47 AM

Post #5 of 17 (6672 views)
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Re: [denonjapan] NEC 42" Plasma shuts off with input signal, stays on without [In reply to]	Can't Post

cool! thanks! Just resolder the video card...or replace it outright? To replace it can you, or someone, point me to the NEC plasma TV video card store??? Thanks very much for your help!

rptvbuyer
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Oct 30, 2006, 4:23 AM

Post #6 of 17 (6665 views)
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Re: [ejm91206] NEC 42" Plasma shuts off with input signal, stays on without [In reply to]	Can't Post

I will ask this, when the screen goes black from the video content. Do you loose sound or does sound get distorted?
When you say it shuts down, do you have to power it off or unplug it to get it to repower up?
rptv

rptvbuyer
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Oct 30, 2006, 4:30 AM

Post #7 of 17 (6663 views)
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Re: [rptvbuyer] NEC 42" Plasma shuts off with input signal, stays on without [In reply to]	Can't Post

OK, I reread your post again. Your explanation is, it is shutting down then. I am not a display expert, but would say it could be the power supply, it is the part that typically has the function to shutdown the set if a voltage level is wrong. If you are interested in parting with set, let me know. It might be the high voiltage section of supply that excites the display. May be needing more current from the supply when video is present and the supply maybe ailing in that it cannot supply enough current for the high voltage so the voltage drops and the supply detects it and shuts down the set. I am assuming you may have to unplug and replug in to get it to power up again?
R.

ejm91206
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Oct 30, 2006, 4:31 AM

Post #8 of 17 (6661 views)
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Re: [rptvbuyer] NEC 42" Plasma shuts off with input signal, stays on without [In reply to]	Can't Post

when it was in the "still working phase" sound would be fine all the way to the point the unit shut down. The coloration on the screen seemed a bit reddish tone though, like not all the greens were firing (but not evenly ...splotchy pink-ish tones).

It will restart with the power button just fine.

rptvbuyer
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Oct 30, 2006, 12:53 PM

Post #9 of 17 (6655 views)
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Re: [ejm91206] NEC 42" Plasma shuts off with input signal, stays on without [In reply to]	Can't Post

What is odd is that it appears from your discussion to all of sudden started to do this. Either way if you do not know how to work on will need to have some look at it. Sorry cannot be more help than this. MY first instinct is probably the power supply since it is shutting down, I would expect a video card to not shut down the set by itself.
R.

ejm91206
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Oct 30, 2006, 5:22 PM

Post #10 of 17 (6650 views)
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Re: [rptvbuyer] NEC 42" Plasma shuts off with input signal, stays on without [In reply to]	Can't Post

Yes, this all happened within 24 hours- auto shut off, weird colors, fade to black, and nonop.

I took the back off, saw nothing obviously burned. I can solder but that's about it.

Thanks for your help fellas. How much are video cards and power supplies for these things?

denonjapan
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Oct 31, 2006, 7:45 AM

Post #11 of 17 (6645 views)
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Re: [ejm91206] NEC 42" Plasma shuts off with input signal, stays on without [In reply to]	Can't Post

power supply has nothing to do of the shutting down, if signals only coming through, triggers the display off, then I am convinced the video card is inferior from the incoming signal of the distribution of primary red, blue green colors. (Possible that causes this was, you may have at one time changing connections while the tv was on + a source player running. where you're not aware those cable was not properly grounded.) People do this everytime....The entire video cards which NEC has in their displays will run you more than $500.00 the most/ if you pursue this experiment, I suggest to look for someone who sells broken displays same model to yours....Doing this is very risky, do not touch those micro chips out of curiousity. ground your fingers (touch something metal, keys ) before proceeding. have fun by the way!
denonjapan
made in japan.

(This post was edited by denonjapan on Nov 2, 2006, 6:44 AM)

ejm91206
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Oct 31, 2006, 4:38 PM

Post #12 of 17 (6639 views)
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Re: [denonjapan] NEC 42" Plasma shuts off with input signal, stays on without [In reply to]	Can't Post

thanks for the tips! I can't afford 500.00 experiments so it looks like I'll take in to a shop and let them do it. :)

denonjapan
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Nov 4, 2006, 6:47 AM

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Re: [ejm91206] NEC 42" Plasma shuts off with input signal, stays on without [In reply to]	Can't Post

Ed, Even if I said that, I want you to understand one thing! I still believe plasma tv malfunctions of any kind still clings the problem after. NO guarantee, it's not going to be successful any work or repair done by technicians. Some maybe able to pinpoint the exact location of the problem but defective parts not subject to be replace.Like I said before, there are no second chances of plasma lifespan. some will last, some exceeds, some won't or even under the predicted 30,000 to 60,000 hours. it can happen in 500 to 1000 hours it doesn't matter........I'm not about to subject you into spending more, thats why i took the risk by telling you to experiment on your own pace, without putting any more money.

Not just you but anybody who will be reading this: Due to high volume of plasma models nowadays, I may not familiar with the year and make but they still share same nature, failing status, nothing has changed on phosphor-based displays. I am sorry if Most of my responses do not include any part nos and ICs, transistors, power supply or direct suggestions to anyone as I have guidelines and ethics in this regard. (Simply, Doctors can't prescribe medication to a patient upon his/her request over the phone unless fully examined, so do I.) Some people take my answers rather insulting if not demeaning, upon hearing the truth (listen! gearguy/ rrobor) but no intention of any kind. I JUST WISHED EVERYONE CAN READ BACKWARDS LIKE WE DO, TO BETTER UNDERSTAND PLASMA TVs/ LCDs AS WE SPEAK.

denonjapan
made in japan

ejm91206
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Nov 8, 2006, 4:14 AM

Post #14 of 17 (6601 views)
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Re: [denonjapan] NEC 42" Plasma shuts off with input signal, stays on without [In reply to]	Can't Post

Denon I think this is a great reply and well thought out. I didn't see the notification in my email and I had actually come back here just now to ask what this thing is worth parting out vs. selling the unit as a whole?
I played with it again the other day, and same thing (but this time it stayed on a little longer, maybe 1 minute with signal input). It would not recognize input from the vcr this time but did see input from the dvd player. Then it shut off again- and when I say shut off, I mean go to standby.

denonjapan
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Nov 8, 2006, 7:18 AM

Post #15 of 17 (6598 views)
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Re: [ejm91206] NEC 42" Plasma shuts off with input signal, stays on without [In reply to]	Can't Post

That's the underlying problem incur to your display. It wouldn't make any difference whether a minute or two. if the problems persisted one from the other source, one has priority. However when signal is detected, it will shuts off one way or the other.

Also your question, if this is worth parting vs. selling the unit as a whole?>>> knowing this won't worth to anybody, I don't see in anybody's conscience will take that chance even if timing allows you so. I wouldn't believe you will pass this along to anyone in order to solve our own, nevertheless leave it to the potential buyer and to their ignorance and by letting them find their own answers somewhere, isn't JUST right. know what I mean?...But! if someone insist of buying this off from you after telling them the consequences, would be fully on their own, then I will have no right to intrude of the deal. Just let the buyer know to stay away from forums. take care!

denonjapan
made in japan

MOtvGuy
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Nov 8, 2006, 12:49 PM

Post #16 of 17 (6595 views)
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Re: [ejm91206] NEC 42" Plasma shuts off with input signal, stays on without [In reply to]	Can't Post

There's far more shutdown circuitry in a Plasma than just in the power supply and there is no "video card" per se.

Most Plasma's have a board that contains the tuner, microprocessor circuitry, audio and analog video circuitry. I can't say that that's what's causing the problem here. Apparently when the panel is forced to fire when a video signal of anytype is injected it's forcing the set into shutdown.

The possibilities include either the X or Y sustain boards going into current overdraw causing the protection micro to detect that and shut the set down. A faulty power supply. or, worse, a bad PDP panel. None of this will be cheap to repair and if it's a panel I'm afraid your set is toast.

denon is right BTW about troubleshooting over the phone or the internet. Unless a problem is common to a specific chassis I see way too many easy answers given out as fixes on this board. The hardest part about troubleshooting consumer electronic equipment is diagnosing the symptom to the circuit involved. Without actually seeing a problem a tech over the internet is likely to send an unknowing non-tech on a wild goose chase.

Good luck with your Plasma.

ejm91206
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Nov 8, 2006, 4:55 PM

Post #17 of 17 (6588 views)
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Re: [MOtvGuy] NEC 42" Plasma shuts off with input signal, stays on without [In reply to]	Can't Post

thanks guys. the question about selling it is I've noticed several people buying plasma units I assume to use as parts for piecing together other units. Is that unethical on some level? I hope not. I think tossing it out if it can be used somehow is a waste.

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