• New Sponsor: ShipNerd, Ship Your Gear with Us... for less! Click Here.

My TV needs a cap job

RussB

low rent hobbyist
Messages
11,157
My Magnavox (Phillips) 37" flat screen LCD TV up and dies the other day. Of course I opened it up and found 2 caps on the power supply board had popped. I ordered few caps from Mouser for $7. It's worth a shot, right? :)






The 2 caps with the black goo coming out the centers are the culprits. The fuse is still meters good...What's up with that?
 

RussB

low rent hobbyist
Messages
11,157
117 to 120 ish


I remember reading about a large lot of caps that were manufactured improperly and these bogus caps found their way into millions of consumer electronics...makes me wonder if these could be part of that debacle?
 

Ronsonic

Member
Messages
3,302
I don't do TVs but there are guys in the shop who do, and this is a very likely fix. You can also google around. TV guys see a lot of the same stuff and share tips.

The bad cap in a switcher thing ---- high probability that will fix it.
 

teemuk

Member
Messages
3,307
Totally worth a shot. Of course I would actually measure if the power supply board is outputting proper voltage outputs before making hasty conclusions, could be something entirely else than just dead caps too.

I don't usually bother to point out about the high / potentially lethal voltages / circuits inside things but in case of TVs and SMPS I feel a fair warning is on place: I don't know about the LCDs but older tube televisions can pack voltage charges of several kilovolts! SMPS filtering caps don't usually have drain resistors, can hold a charge for days and they usually have quite high voltage potential! (Some are filters for rectified mains voltage). Also, the SMPS is most likely in direct connection with the mains, no isolation transformers are used! Due to that, depending on design, "ground" reference may actually carry a high voltage potential.
 

guitarcapo

Senior Member
Messages
2,326
I have a Samsung that blew its mercury lamp. While researching how to fix it I was amazed at how many failed cap incidents were out there. I assumed it was just a vintage tube electronics problem with their high voltages. But that gets reported often.
 

myfoot

Member
Messages
61
I actually just had my 46 inch Sharp fixed and found out it was a bad cap in the power supply. It was taking longer and longer to turn on.
 

RussB

low rent hobbyist
Messages
11,157
I actually just had my 46 inch Sharp fixed and found out it was a bad cap in the power supply. It was taking longer and longer to turn on.
Bada Bing

This is the symptom my TV had been experiencing before it simply wouldn't turn on anymore
 

Trout

Member
Messages
7,549
I would not worry about line voltage to much on TV's as they were built for the US market anyway.

There has been a huge number of instances of bogus caps in TV's the past 5-8 years. They even resulted in a few recalls.

Check out info over at Badcaps.net
http://badcaps.net/

They are a great resource for cap kits made for consumer electronics. They also have decent forum and loads of info on what to look for and replacement tips.

Cheers
 

ClinchFX

Platinum Supporting Member
Messages
878
I remember reading about a large lot of caps that were manufactured improperly and these bogus caps found their way into millions of consumer electronics...makes me wonder if these could be part of that debacle?
Russ, the story as we knew it is that the electrolyte was corrosive and ate its way through the seals. It was particularly bad in SMD caps in items such as video cameras that are often left in the extreme heat of a car.

My wife, Mandy, is a hot shot camera tech who has done hundreds of complete SMD capacitor replacements in cameras. This includes cleaning all the leaked electrolyte from the PCB. Many cameras were written off because the electrolyte had severely corroded the multi-layer PCB.

The cap failures in your TV may be, more likely, the result of inadequate specification by the manufacturer combined with heat build-up in the power supply area of the PCB. You should be replacing them with 105 Degree (celsius) caps that have low ESR and a high ripple current spec.

SMPS filtering caps don't usually have drain resistors, can hold a charge for days and they usually have quite high voltage potential! (Some are filters for rectified mains voltage). Also, the SMPS is most likely in direct connection with the mains, no isolation transformers are used! Due to that, depending on design, "ground" reference may actually carry a high voltage potential.
I suggest that you heed this warning from teemuk.

Peter.
 

RussB

low rent hobbyist
Messages
11,157
I would not worry about line voltage to much on TV's as they were built for the US market anyway.

There has been a huge number of instances of bogus caps in TV's the past 5-8 years. They even resulted in a few recalls.

Check out info over at Badcaps.net
http://badcaps.net/

They are a great resource for cap kits made for consumer electronics. They also have decent forum and loads of info on what to look for and replacement tips.

Cheers

I got this pic from the badcaps website, Note that the black/gold caps that failed here are the same brand as the one's that failed in my TV


 

Trout

Member
Messages
7,549
I got this pic from the badcaps website, Note that the black/gold caps that failed here are the same brand as the one's that failed in my TV


Been there myself, I recapped several motherboards over the past few years. Same thing, they were obviously either generic junk or fakes that made their way into mass production.

This has actually been a rampant problem in all consumer electronics and even made its way into military gear as well.

Remember a while back Weber had been hit with bad caps as well.

Some are not even the correct value inside,


 

RussB

low rent hobbyist
Messages
11,157
Yeah, I remember the "Great Weber Cap Debacle" I also had several Weber-supplied caps fail in short order
 

XSSIVE

D'Avanzo Guitars
Silver Supporting Member
Messages
1,606
I've saved two PC monitors and a TV due to bad caps. All had the same longer and longer turn on time problems yours did 'til they wouldn't turn on at all. Makes me glad I learned to solder all those years ago working on R/C cars and slot cars then taking that to pedal building and guitar building.
 

jamison162

Member
Messages
7,750
Same here, I've repaired two Acer 19" LCD monitors and a huge LCD TV someone threw away by replacing a couple of caps on the PSB. < $5
 

RussB

low rent hobbyist
Messages
11,157
The parts came in today. I installed 4 caps and a diode...plugged it in an voila!

It only takes a few seconds to come on now. I deserve a cookie



 

Trout

Member
Messages
7,549
Excellent, 15 bucks + your time = a $600.00 or more TV. Just like the good old days!

Well Done!
 






Trending Topics

Top Bottom