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any electriction/hobbyists out there help??

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NHdave

New Member
Joined
Aug 4, 2010
Messages
16
Location
New Hampshire
I was a bar I frequent today and the owner was throwing a 42" samsung plasma tv out into the dumpster... I asked if it was broke and he said "well the thing keeps clicking and trying to "turn on and off.. so I said ***it and got a new one..." I asked if i could have it and he said sure. So I got it home, plugged it in and turned it on... came on perfect picture and sound for about 10 minutes.. then it turned off and did the thing he was talking about..
from the research I've done online it seems to be a problem with some capacitors not having a high enough voltage rating for the power they recieve??? I am VERY VERY unknowledgeable when it comes to electronics, but this 'sounds' like it could be a DIY, inexpensive fix... am I wrong? I obviously don't want to pay a tech 3-6 bills for a whole new board (if required I will just craigslist the thing) if it is something I could do with some simple soldering and 10-20$ worth of parts... ANY advice is appreciated, IE: what to look for, where to look, is this what it wrong etc... Thanks!!
 
I would start by removing the circuit board, taking a magnifying glass and looking for cold solder joints underneath. They will look like a microscopic crack that runs completely around the solder joint of the component and the board. This is by far the easiest fix. Heat as well as cold can cause a cold solder joint to separate, breaking the component connection.

Outside of that, I know enough about electronics to know that either you pay to have it repaired, or you donate it and take the tax write-off, which in some states can be very lucrative...

You might want to try getting a hold of the field repair manual that has all the T-shooting and component values for testing.
 
I would look for electrolytic capacitors that are bulging or leaking. I know there was a bad batch that made it into computers some time ago. Most electrolytic capacitors look like a can with a stripe with "+" marks going down one side to indicate the positive lead.

-- Tom
 
I had a Toshiba 42" rear projection that had lost a color (red). I Googled the issue and there was lots on information on a $25 capacitor usually being the culprit that would need replacement. It gave me the part # and showed where it was located. Try Googling your problem also and it may be a common fix.
 
Write down the uF and voltages of all electrolytic caps, and order them from PartExpress. If the voltage isnt available, order the next highest value.

If you need any order supplies such as a solder sucker etc it would also be a good time to get it.

When the parts arrive, mark the + location of each cap and desolder the caps ONE at a time and clean, resolder, making note of the polarity as you do.

When you've inspected your work and your happy with the results, re assemble and test the plasma.

Good luck!
 
ok... so I just took off the back of tv, and tried looking for obvious signs of blown caps (I went on google and youtube and found tons (hundreds) of people with the same problem talking about this being the culpurit, and expected to see the bulging or oozing caps.... however... I checked all of them (visually) and couldn't see anything wrong with them, Damn!

I am also a little bit sketched about touching stuff because I have read varying stories about how long the caps can hold juice, some say after a day it is ok to touch stuff, others said that the power can stay in there indefinitely, I
don't feel like getting jolted over something stupid. saw something about using screwdriver to uncharge them, etc.. any actual answers on this?

I feel I might be in over my head, but as it was a free tv, I kinda want to use it as a learning experience....

Also: how do I tell difference between electrolytic caps and *non*electrolytic?? are all electrolytic the ones with the silver "x" on top to allow gas to escape if overloaded? also... there are varying sizes IE: some are tiny, some are 10v, some are 35v or something, and obviously there are the big 350v or whatever(guessing I shouldn't mess with those ones)
 
If you think caps hold juice, some picture tubes can hold 25,000 volts. A picture tube has to be discharged. Not sure what kind of tv you have but be careful. Here is something you might find interesting http://books.google.com/books?id=tt...nepage&q=picture tube holding voltage&f=false Check out page 296

Just reread your post and noticed you said it was a plasma tv, sorry about the mix up on my part thinking it was an older picture tube model :doah:
 
just to clarify, the problem with this tv is something to do with internal components, I am guessing somewhere between the power supply and whatever comes after that lol to the tv, because after it has been sitting for a few hours, I can plug in turn on and it works perfect (for about 3-5 minutes) then shuts off and does the "clicking on off" thing, where I can hear the thing 'trying to turn on' etc..
 
NHdave said:
just to clarify, the problem with this tv is something to do with internal components, I am guessing somewhere between the power supply and whatever comes after that lol to the tv, because after it has been sitting for a few hours, I can plug in turn on and it works perfect (for about 3-5 minutes) then shuts off and does the "clicking on off" thing, where I can hear the thing 'trying to turn on' etc..
Click to expand...
I don't know much about plasma tv but I wonder if it could be a thermal thing.

You probably already seen this but if not here you go http://www.consumeraffairs.com/home_electronics/samsung_tv.html
 
yeah definitely not going to buy a samsung, crazy that they didn't recall all these tvs.... My westinghouse lcd has been going strong for 5 year w/out a problem (i even dropped it moving into our new house last year lol)

I wish I knew someone locally that was just a hobbyist could come check it out and give me some pointers...
 
NHdave said:
yeah definitely not going to buy a samsung, crazy that they didn't recall all these tvs.... My westinghouse lcd has been going strong for 5 year w/out a problem (i even dropped it moving into our new house last year lol)

I wish I knew someone locally that was just a hobbyist could come check it out and give me some pointers...
Click to expand...

I know a few people with samsung sets and so far no problems. Every company is going to have a bad run with a tv.

Sony had those old trinitron sets that the picture would blink after you turn it on.

Anyway, not a electronics expert, but it sounds like a bad soldering problem.

Sounds like a component is not firmly soldered to the board, and when it warms up, it expands and looses contact. When it shuts off, it cools enough it makes contact, turns on, the heats up, and loose contact. Cycle repeats.

I would take a wooden dowel rod, and when it starts doing it, press on components in the power suppl, if something causes it to work, then you know what needs to be re-soldered. It's not very hard to do.
 
Hey a 42" Samsung Plasma:D Thats my TV. Its an HP-S 4253 model that just clicked and never came on. It was the power supply but looking on the board I found no bulging capacitors or signs of overheating.
I took it to a repair shop and it cost 270 dollars to fix. The guy said it was a common problem and said in the future to buy an LCD or LED because the power supply is less expensive and the plasma reqires a larger juice hungry power supply. I did find a power supply on line using the number on the circut board it was I think 125 dollars but I didnt want to spend money without knowing for sure so I let a pro do it.
 
Hi NHdave,

All electrolytic caps are barrel shaped. They are usually in a blue wrapper with a silver colored flat top. If you would go to PartsExpress and type "capacitor" you would see what the electrolytic look like. Just because you can't see them leaking or bulging doesn't mean they aren't bad.


Write down the ratings that you see on the board,

1 x 15v 270u
2 x 35v 4700u

etc

Secondly, I had a 42" Samsung, and had to threated to sue them to get my repair done. When the guy changed the board I asked him to replace the caps and he had a whole bag of them, as this is such a common problem for Samsungs.

This is not a few bad sets, it's enough to have a class action law suit. However, it was the manufacturer of the caps that is the root problem, and Samsung's treatment of their customers that is secondary.

NHdave - don't worry about the voltages on the board etc, I wouldn't have given you those instructions if this was an issue. If you still think it has magic dust in it and you can't trust my decades of experience, then turn the set on and while it is still running, pull the pwr cord. This will deplete the charges in the power supply circuits reasonably enough.

For less than $20 and 30 minutes of your time, you maybe can have this fixed. If this doesnt fix it, then you had fun in the process.


.
 
NHdave said:
I was a bar I frequent today and the owner was throwing a 42" samsung plasma tv out into the dumpster... I asked if it was broke and he said "well the thing keeps clicking and trying to "turn on and off.. so I said ***it and got a new one..." I asked if i could have it and he said sure. So I got it home, plugged it in and turned it on... came on perfect picture and sound for about 10 minutes.. then it turned off and did the thing he was talking about..
from the research I've done online it seems to be a problem with some capacitors not having a high enough voltage rating for the power they recieve??? I am VERY VERY unknowledgeable when it comes to electronics, but this 'sounds' like it could be a DIY, inexpensive fix... am I wrong? I obviously don't want to pay a tech 3-6 bills for a whole new board (if required I will just craigslist the thing) if it is something I could do with some simple soldering and 10-20$ worth of parts... ANY advice is appreciated, IE: what to look for, where to look, is this what it wrong etc... Thanks!!
Click to expand...

Sounds like a power supply problem. What I usually do with TVs/Monitors is throw them on Ebay and start he Auction for $99.99, let them know that the item does not work 100% and what the symptoms are, then I find someone who buys it because either they are in the business or they k now someone who is, I get between $100-$200 for each broken item, then I pocket the cash. Case closed! I don't even try and fix Flat Panel anymore.
 
FL-Hunter said:
Sounds like a power supply problem. What I usually do with TVs/Monitors is throw them on Ebay and start he Auction for $99.99, let them know that the item does not work 100% and what the symptoms are, then I find someone who buys it because either they are in the business or they k now someone who is, I get between $100-$200 for each broken item, then I pocket the cash. Case closed! I don't even try and fix Flat Panel anymore.
Click to expand...

When they are charging you $270 to fix a TV set it's not worth fixing. Your approach is an excellent idea. When my 42" HD Toshiba rear projection had it's issues, even though I knew the capacitor replacement was cheap, I didn't have the electronics skill to do it nor did I want to spend hours taking a TV apart. I donated it to my Scouts who are going to use it as part of an Eagle project. My new awesome 42" off brand HD LCD cost $400.
 
thanks for the replies guys... honestly since this tv was free, I'm really more interested in trying to fix it, and I don't believe it is going to be something 'out of my realm' as do know how to solder, I just don't have any experience with electrical stuff, I want to use this as a project, and if it works great...

captain morgan, how do I know which capacitors to replace.. there is everything from little guys up to 450v or something
 
plasma tv's are junk!!!!!!!!!!!!! plasma burns up in about 5 years... waist of hard earned money. the manufactures new this when they made them so you keep buying a tv. the plasma will also freeze on you if below a certain temp. DO YOURSELF A FAVOR AND DO WHAT THE GUY DID BEFORER YOU AND BUY A HIGH DEF L.E.D TV OR L.C.D. . THAT IS LIGHT EMMITTING DIODE OR LIQUID CRYSTAL DISPLAY. THE LCD ALSO HAS A FREEZING ISSUE BUT TO BLOW $3000.00 dollars on a plasma to buying a nice HIGH DEFINITION l.e.d or l.c.d for around a $1000.00 is a big difference and with less head aches. just MY OWN OPINION. ;)
 
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