TV Woes

[Ramjo]

Came back home this evening to a non functioning tv. We had a storm and there was reportedly one loud pop of lightening close by. Everything is plugged into one of these fancy $100 power strips, and everything else seems to work fine. The tv will turn on with the remote, but just sits on a black screen. It won't respond to any other buttons on it or the remote. Hitting the power button results in the thing turning off and then back on after a delay. No blinking lights of death.

It's a panasonic viera plasma tv.

 

The internet says it could be fried capacitors, but these usually require having some form of blinking light or weird noises coming from the tv.

Any ideas?

[Sam1]

almost impossible to troubleshoot tv electronics unless you've got experience + the equipment.

[JGunner]

My Vizio screen started flickering across the entire screen, and my research turned up that it could be blown capacitors. Sometimes (I'm not sure if always) a blown capacitor will be poofed up on the top. This allowed me to find 3 capacitors next to each other that were blown. I replaced these 3 capacitors with parts from the local electronics store (Shields off Hwy153 in chattanooga) and that fixed the problem.

My overall point is sometimes you can visually see a blown capacitor. If you have the soldering skills you can then replace said capacitors. Good luck!!!

[Sam1]

That's called "distended" basically the top of almost all capacitors will extend out when they blow.  The other thing is when a circuit shorts out, it will smell like band-aids so you could smell around too, but honestly unless you are risking damaging it more by messing with the stuff.

 

Have to ask yourself, is it worth the $50 or $60 to have someone diagnose it, or worth risking your tv to save that $50.  

[Ramjo]

Hmmmm  :-\

[Guest TankerHC]

Depending on brand and if you have a receipt all good surge protectors come with a guarantee. If you blow electronics through a lightning strike or some other surge the manufacturer will pay for the blown electronics. Many do not even require a receipt. Most guarantee at least 50,000. Couple of mine are 100,000 and my BackUPS is 250,000. For a 100 dollar protector they should easily cover the TV. But you do have to send it in, in most cases to be tested.

[NoBanStan]

Surge protectors are for protection against surges and brownouts, not so much lightning strikes. I would advise unplugging any valued electronics during lightning storms. This includes not only the power but other connections such as telephone modems and coaxial. People often forget those.

[Jonnin]

you do not have a lot you can do at home.   Thankfully expensive power strips replace items lost, hopefully yours has the $10k replacement value clause?  Take a look!  They are supposed to have a fuse or breaker type thingy that you can manually reset which is supposed to trip on a big hit. 

 

I would try at total unplug, then turn it on with the remote. Wait 1 min and plug it back in.  Try it again. 

 

Capacitors are the current weak link in modern cheap electronics (or even sometimes in expensive stuff).   They are poorly made (cheap!) and you are lucky to get 5 years out of something.  Naturally spikes and surges can shorten this...  

Edited June 3, 2013 by Jonnin

[viscero]

Home owner's insurance will usually cover a lightning strike in my experience.  Just depends on how bad your deductible is and the overall cost of a replacement unit.

[Guest Lester Weevils]

Are the caps subject to blowout in TV's nowadays to be found in the switching power supply or somewhere else? IOW, do these tend to be high voltage caps?

 

Just curious, as in the old days ordinary old low voltage or medium voltage caps didn't seem any more likely to fail than any other category of part. Sometimes tantalums seemed a little more likely to go bad.

[Ramjo]

Well, I have had the TV for quite some time now...come to think of it, it may be going on 4 or 5 years old. I had read the life expectancy of plasmas was 10-15 years. Obviously, lightening can greatly shorten that.

[mikegideon]

Caps usually fail over time by drying out. They never fail due to a surge. It's possible the brains in the TV got scrambled. I would unplug it and let it sit for a few minutes, then plug it back in. More likely than not, you have damaged semiconductors. In this day of disposable electronics, it may not be worth fixing unless you have the skills to do it yourself.

[Jonnin]

Are the caps subject to blowout in TV's nowadays to be found in the switching power supply or somewhere else? IOW, do these tend to be high voltage caps?

 

Just curious, as in the old days ordinary old low voltage or medium voltage caps didn't seem any more likely to fail than any other category of part. Sometimes tantalums seemed a little more likely to go bad.

 

Its not the ones in the TV, its the cheapos that are put on printed circuit boards.  That is, its not the "big" capacitors that work on direct AC or whatever, its the little ones on the PCB that have gone to being junk in the last decade or so.  As said, they dry out and then short out or fail some other way (?).   I have seen them double in size when they fail, or burst.    Ive seen it happen from simply turning something old off and back on, and can only assume that a power surge *could* do something.   It may not be the capacitors anyway, those are just one very common point of failure of some 20 contenders.  

 

It could be the power supply, any of the electronics (chips, memory, etc) or the screen itself. 

[Ramjo]

Unplugging it and powering off/on does nothing different. It has been turning itself off and on tho when I left it on...

[mikegideon]

Unplugging it and powering off/on does nothing different. It has been turning itself off and on tho when I left it on...

 

http://www.bestbuy.com/site/Electronics/TV-Video/abcat0100000.c?id=abcat0100000

[Guest Lester Weevils]

Its not the ones in the TV, its the cheapos that are put on printed circuit boards.  That is, its not the "big" capacitors that work on direct AC or whatever, its the little ones on the PCB that have gone to being junk in the last decade or so.  As said, they dry out and then short out or fail some other way (?).   I have seen them double in size when they fail, or burst.    Ive seen it happen from simply turning something old off and back on, and can only assume that a power surge *could* do something.   It may not be the capacitors anyway, those are just one very common point of failure of some 20 contenders.  

 

It could be the power supply, any of the electronics (chips, memory, etc) or the screen itself. 

 

Thanks. Thats a shame if such old tech has gone sour. Back when I did hardware hacking one could buy big baggies of such as moderate-voltage small-to-medium ufd panasonic electrolytics CHEAP from such as DigiKey. They were very long-lived and reliable as far as I could tell. Also used to stock baggies of polystyrenes and mylars for filter circuits, and mica and ceramics for bypass caps and such. And good old sprague orange drops. Well actually, still got a bunch of em somewhere or t'other in cardboard boxes. Can't get around to giving them away because you never know, one of these days a feller might need a few caps. :)

[Ramjo]

http://www.bestbuy.com/site/Electronics/TV-Video/abcat0100000.c?id=abcat0100000

MIKE! I don't wanna spend money! lol