Official Westinghouse TX Series ( TX-42F430S, TX-47F430S ) Owner's Thread - Page 202

Thanks CD, one more question. What temp did you use when you desoldered the caps?

My previous post identifying the bad cap..."That capacitor should remain a 470uF but the voltage can be higher...the other guy put in a 25V...I'd prefer to stay at 16V but make sure it's one designed for switching power supplies...not general purpose because it gets a lot of pulsing from the LC circuit it's in...I think they're called low ESR caps. Be careful when de-soldering the leads that you don't over heat the PC board...follow my instructions and use a solder sucker as an iron by surrounding the leads and tilting the cap back and forth from one lead to the other until it is loose - then suck out the solder or stick a needle through the hole from the component side so the replacement cap can be inserted. Re-solder the connections using that same iron so it heats it up thoroughly to get solder to surround the lead into the hole. Good luck! Dave"

I use a Radio Shack dual heat 15/30wt bulb type solder sucker on the high setting! Again, ease the cap out by heating one lead, then the other while rocking it up and out of the holes gently one "tilt" at a time. I was determined to find out which component was going bad and it looks like all you other guys verified that the worst of the "bad" caps is that 470uF 16V...what a shame to cause a really good set with lots of features to fail because of a 50 cent part!!!! Mine only lasted 4 years before going bad. Also, I've noticed on some caps on the laptop main boards that I repair that some have a suffix of "A" while others have a suffix of "E" - I assume A means audio since they're in the audio output section of a laptop and the E are in switching power rail circuits so I believe they are the low ESR type! Pretty intuitive but it took me a few looks before I noticed that difference. Thanks to all for sending in your own experiences.

To squirrellydw:
I put the soldering iron all the way up to 420C.
The hotter, the better. The idea is to melt the solder as fast as possible, before the heat can dissipate through the board and damage other things.
I have had problems when I have kept the soldering iron tip on the board for too long. This can happen if your tip is not hot enough, if the solder melt temp is too high, of if the board is too thick and the heat dissipates sideways before the entire column of solder can melt.
I suggest that first you apply a little liquid flux compound to the old solder, this will make the solder flow better.
Then you should melt a little new solder on to the old solder. That will increase the surface contact area between the iron and the old solder and increase the rate of heat transfer.
As orgwood has stated in his post, you melt one terminal and rock the capacitor a little and then melt the other terminal and rock the other way. Back and forth until it is free.
The last part is to get all to old solder out of the hole so you can slide in the new cap. That is where the solder sucker is used.
Electrolytic caps are polarized, the side stripe indicates the negative terminal. So be sure the stripe is on the correct side when you insert the new cap.