Need some expert advice

[kllttfam]

I have an Samsung LCD TV that I need to replace a 470uf 10v 105 degree centigrade electrolytic capacitor on the power supply.
I ran out to Radio Shack today since they were the only place open and the closest thing they had to what I needed was a 470uf 35v 85 degree centigrade electrolytic capacitor that is a little larger than the on there now but it looks like it would physically fit.
My question is with the temperature rating being so much lower do you think it is a good idea to put it into my power supply?
The 35v being higher is a little concern also but I was planning on going up to a 16v, not necessarily as high as 35v but I guess that is a good question to add in also.
Any advice given would be gladly appreciated

[paulstef]

Re: Need some expert advice

Voltage rating can always be higher but not lower. Although other parameters may change too at the same time.

As for the temperature rating: If it runs in a higher temperature range it will probably last less longer than one for 105C.

I would mainly look out for ripple current, voltage and ESR specs.

I don't think there will be any problem using the one 85C. If you want to be sure you post both model numbers here and we can check their datasheets. Or better post pictures that show their number (not value or voltage rating) and manufacturer name or logo.

[mariushm]

Re: Need some expert advice

Radioshack doesn't stock good quality capacitors generally.

LCD TVs, monitors etc use switching power supplies, which need capacitors that have certain characteristics such as low esr and high current ripple, something that those 85c Radioshack capacitors don't have.

The TV may work if you use that capacitor, but not for a long time.

The voltage on a capacitor is the maximum voltage that the capacitor can handle. You can use capacitors with higher voltage than the voltage written on the faulty capacitors, provided the technical specifications are very close or exceed the specs of the old capacitor.

I would not recommend using that capacitor because it's not suitable for switching power supplies and the back of your TV will be hot so it won't last a long time. As a temporary fix (a few days) it may be OK to solder in place.

You can order good capacitors from this site ( https://www.badcaps.net/store/produc...roducts_id=119 or https://www.badcaps.net/store/produc...roducts_id=148 are good choices ) or you can get them from an authorized distributor of quality capacitors such as http://www.digikey.com or http://www.mouser.com ( I would recommend Panasonic FM or Panasonic FR from these two sites)

[kllttfam]

Re: Need some expert advice

Wow, Thanks great advice from both. I can see what you saying. I am attaching photos just for poops and giggles but I think that I agree that I should be looking for higher quality than the Radio Shack parts.
I think, however, that I am going to go ahead and pop this one in just to see if it does indeed correct the issue that I was having with the TV while I am waiting on the new one to arrive and to possibly eliminate any additional issues I may have including needing to replace the entire power supply itself.
They only go for $50.00-$60.00 these days and it doesn't seem like a whole lot to spend just to drop in a complete new one instead of continually trying to take apart the TV to trouble shoot the issue if just replacing this 1 CAP doesn't fix it.
However if this is it and I can order a better quality one for a few bucks and do that just 1 more time then it was time well spent and I thank you both for your help.

[paulstef]

Re: Need some expert advice

Well, IMO the original caps weren't THAT good if they already need to be replaced. Either that or they were used near or above their maximum ripple current rating. I say you should give the ones from RS a go. Sure you can always better ones if you really want to.

I do not agree with replacing a whole board, especially not a single layer PSU PCB. If you can afford the time I recommend troubleshooting until finding THE components which are damaged. You learn really a lot doing it the hard way.

[clearchris]

Re: Need some expert advice

If you are ordering parts, Id replace all those caps. Caps have a lifespan to them, and the same types generally go around the same time.

[kllttfam]

Re: Need some expert advice

Thanks. I am trying it tonight and let's see what happens. I'll keep you posted. I ordered a couple of CAPs from Mouser just in case. I was looking at the specs the ripple currents on the RS CAPs are not even half what those on the Panasonic's are from Mouser so for the .61 I figure why not? If this one blows I will pop in the Panasonic and see how it does.
I was just thinking about how I threw away my last surround sound and I just know it had to be the same thing.
Wish me luck, now I am off to give it a try.
There's a noob with a soldering iron and a whole lot of praying going on over here.

[kllttfam]

Re: Need some expert advice

just wanted to thank you guys for your help. Ever since I put in the new CAP the TV is working just fine even though I did install the RS CAP.
I did receive my new Panasonic CAPs the other day and am debating whether I should even bother to put them in now or wait to see if the RS one goes bad (will it even go bad or if it does will it do any damage?) or just see what go ahead and be proactive? My soldering skills are definitely not all that and I hate just taking things apart for the fear that I may wind up damaging something else unintentionally. The Panasonic CAPs are definitely rated better and have the higher ripple current rating and temp tolerance. Do you think it would make any kind of performance difference in the TV set at all. Nothing looks any different to me right now. Other than the set is working of course

[germaldish]

Re: Need some expert advice

If it ain't broke, don't fix it! That's my two cents!

[Agent24]

Re: Need some expert advice

just wanted to thank you guys for your help. Ever since I put in the new CAP the TV is working just fine even though I did install the RS CAP.

That's good, it proves that the capacitor was the problem.

I did receive my new Panasonic CAPs the other day and am debating whether I should even bother to put them in now or wait to see if the RS one goes bad (will it even go bad or if it does will it do any damage?) or just see what go ahead and be proactive?

Yes you should install the high quality ones. The one you got from RS will not last very long here, since it is a general purpose capacitor. The other original ones are likely on their way out too. Proactive replacement of crap caps is a good idea. When bad caps die they can cause damage to other things too.

My soldering skills are definitely not all that and I hate just taking things apart for the fear that I may wind up damaging something else unintentionally.

For soldering, try this: https://www.youtube.com/watch?v=I_NU2ruzyc4

For taking apart - you already took it apart before, so you know how Just go slowly and carefully.

[kllttfam]

Re: Need some expert advice

You know, I going to have to agree. Going ahead and replacing all of them (there are only 5 anyway) with the good Panasonic's will probably keep the TV running longer. I do not think it was all just caused by the CAPs themselves anyway. We have a pretty inconsistant power service here and even though we have not lost power recently we do get pretty good fluctuations in current. We blow out incandescent light bulbs like they are going out of style! Oh wait....
anyway it probably can't hurt and the set was not cheap so I would rather have the better ones installed than to have to replace something more expensive then a couple of dollars worth of CAPs even though the whole power supply is only about $60.00 these days.
Thanks for the tip on soldering. I am going to give it another try with some practicing. I also found a good tip on refurbishing some rechargeable Black & Decker 18V batteries which normally cost $40 to replace but if you buy a low cost brand that is similar you can do some modifications with some soldering and redo 3-4 of them for the price of 1! so that should give me some practice. Thanks again!

[cheapie]

Re: Need some expert advice

We have a pretty inconsistant power service here and even though we have not lost power recently we do get pretty good fluctuations in current. We blow out incandescent light bulbs like they are going out of style! Oh wait....

It sounds like you could benefit from a good UPS with AVR. They can correct power fluctuations, in addition to having a battery backup. There are also standalone AVRs, but they're harder to find.

[Agent24]

Re: Need some expert advice

Power fluctuations are unlikely to blow the output capacitors. Maybe the primary one(s) (or more likely the switching transistors), but not the others unless you get some cascade failure of the whole PSU, I think.