Need advice for power problem

[lucyboop]

Hi, I have a 37 in Philips LCD HDTV it's almost 5 years old. About 3 weeks ago it turned off unexpectedly. It did it more frequently and I had to constantly hit the power button until it would turn back on and once it was warmed up it stayed on without a problem. Just this week it got decidedly worse. It was taking upward of a half an hour of constantly hitting the power button on the remote or the actual TV and then it would stay on maybe a minute, 10 minutes or so and then pop it would go off. Now here's the BIG problem. I had a TV repairman come to my house yesterday and he changed all sorts of things on the power supply. The first thing he noticed was the set of three capacitors that were bulged out and had a black dot on the top. They were CapXon 1000uf 35v He put in Nichicon 2200uf 25v. The other bad one was a CapXon 2200uf 16v. Now I'm a single mom and don't know shit about voltages and the uf stuff and he said he was giving me more filtering blah blah. I thought he knew what he was doing. So he replaced them, the TV worked fine and he left. About 10-15 minutes later or so I heard a big POP. I thought should I call him? Is this normal or is it just breaking in, I don't know. Well I called him and he said that's not good and he would come back tomorrow and replace it. Then another POP happened and about 5 minutes after the second POP I lost the picture and the TV started chirping like a bird. I called him and he came back. He changed I don't know how many things and nothing would change, no picture and the chirping. Did he mess up my TV beyond repair? Would a whole new power supply board fix it? I watched him and I could put in a new board no problem but I don't want to buy one if he messed it up beyond repair. I am so mad!! I never had the chirping noise or no picture before, just the turning on and staying on problem. I can take pictures if needed of what he did back there but I thought I would start here first with the story. Any advice would be appreciated! I'm now watching a tiny 19 inch in my large living room and I can barely see it! Thanks!

[retiredcaps]

Re: Need advice for power problem

Hi, I have a 37 in Philips LCD HDTV it's almost 5 years old.

Some housekeeping items first.

1) It would help if you posted the model number. There is also a subforum here titled "Troubleshooting TVs and Video Sources" for future reference.

2) A few paragraphs would also make your post more readable and thus more likely to get help.

They were CapXon 1000uf 35v He put in Nichicon 2200uf 25v.

3) There are a lot of Philips LCD TVs that have capacitor problems. If it is the one I'm thinking about, the 1000uF 35V caps are REQUIRED because they are part of the 24V rail.

4) By putting in a 25V replacement capacitor, the margin for safety is a scant 4.166% ((25-24)/24). So if the voltage creeps up just even a little over 25V, the caps go POP.

5) The power board should be clearly marked with the voltages next to all the cable connectors. If one of the connector legend says 24V, then putting in a 25V cap is asking for trouble. If the legends says 12V or 19V, then putting in a 25V cap is okay. Changing it from 1000uF to 2200uF is another explanation.

6) The POP could also be because he put the capacitors in backwards. Capacitors have polarity, positive and negative. We can tell if you provide a picture.

Would a whole new power supply board fix it?

7) Yes, but a brand new board is likely to have the low quality Capxon brand caps.

I never had the chirping noise or no picture before, just the turning on and staying on problem.

8) A chirping noise indicates the power supply is trying to start, but failing. It could be the new caps he put are totally blown. At worse case, the caps could have damaged other components like a diode.

I can take pictures if needed of what he did back there but I thought I would start here first with the story.

9) Post clear focused top down view pictures of your power board following the instructions in my sig file below EXACTLY.

10) The replacement caps MUST BE low ESR capacitors. These are very specialized capacitors and are REQUIRED for the proper operation of an SMPS.

11) My standard answer for capacitor replacement (regulars may skip).

https://www.badcaps.net/forum/showpo...84&postcount=3

[kaboom]

Re: Need advice for power problem

They were CapXon 1000uf 35v He put in Nichicon 2200uf 25v. the TV worked fine and he left.

That's all you needed to know. You NEVER go lower in voltage. This is not a case of going from a 16V cap to a 10V cap on a 5V motherboard circuit.

About 10-15 minutes later or so I heard a big POP.

Cap blew.

I thought should I call him?

No. Call someone who knows what they're doing.

Well I called him and he said that's not good

Really? Should be working for dork squad.

Then another POP happened and about 5 minutes after the second POP I lost the picture and the TV started chirping like a bird. I called him and he came back. He changed I don't know how many things and nothing would change, no picture and the chirping.

Another cap, and now the PS is overloading. Shorted diodes probably, although it could be the caps pulling it down. Parts monkeys do not even know how to check fuses, much less semis. You won't even need diode check on a DMM, just use "beep" to check them. At least one is shorted. He "went through the motions" of changing things to "pull the wool over your eyes" and make it seem justified to charge you again. I hope you stood your ground and didn't pay again, for his mistake no less.

Did he mess up my TV beyond repair? Would a whole new power supply board fix it? I watched him and I could put in a new board no problem but I don't want to buy one if he messed it up beyond repair. I am so mad!! I never had the chirping noise or no picture before, just the turning on and staying on problem. I can take pictures if needed of what he did back there but I thought I would start here first with the story. Any advice would be appreciated! I'm now watching a tiny 19 inch in my large living room and I can barely see it! Thanks!

I'm sorry you've gone through this. It seems like people who want to have their stuff fixed and would appreciate it only end up with hacks, and those who do know what they're doing get blown off by people who'd rather "throw out and buy new."

New, quality caps of the correct value/voltage and ESR will take care of the "cap problem." Then a few minutes checking the semis and noting what's bad. Some new ultrafasts maybe. Don't forget the "small caps" in the aux circuit of the UC3842.

[lucyboop]

Re: Need advice for power problem

To be honest, that's one of the disadvantages of being a single woman. It's the old stereotype of "let's take advantage because she doesn't know diddly." He didn't charge me for coming back and I did get my money back that I paid him the next day minus the trip charge. In all honesty he should of paid me everything back but I'm not going to argue all day when I did pay him to diagnose it.

Thanks Kaboom for taking the time and not talking down to me. I trusted that what he was telling me about the voltage was true. I'll know better next time. By the way the model is 37PFL5322D. I guess I should feel lucky that I got almost 5 years out of it with the CapXon capacitors. I have the TV on a lot so that's pretty good I guess.

I wouldn't know who to take the board to fix it. There aren't a lot of repairman around here. Hell, if I had a soldering gun I'd do it myself. Thanks again!

[shovenose]

Re: Need advice for power problem

Well, it sucks that a simple problem due tocaps turned into something complex due to that idiot of a "repairman"...
You could start by opening the TV and seeing if the Nichicon caps he put in were the cause of the POP noise... you'll be able to tell quite obviously...
Hopefully you have the original CRAPXons still?
If indeed you do, if you post the specs on them and the series of them, we can advise suitable replacements. Then, you can get an inexpensive soldering iron and some solder, order the replacement caps we've advised, and see if that fixes the problem.

I don't recommend just buying a new power supply because there's a huge chance it will have the junky CRAPXon capacitors on it, which will just die again further down the road.

[lucyboop]

Re: Need advice for power problem

I didn't take a picture of the originals but this is what they say:
1000uf 35V GF 105 degrees C P709 vent (those three were glued together on the original power supply. Then the other single one says: 2200uf 16V GF 105 degrees C P727 vent.

He also put in a part # NTE6083 a Schottky Barrier Rectifier?

Hope these pics help.

[Agent24]

Re: Need advice for power problem

I don't recommend just buying a new power supply because there's a huge chance it will have the junky CRAPXon capacitors on it, which will just die again further down the road.

If the original 'repair' did cause major damage to the first PSU then that might not be a bad idea though - save a lot of time.

Then replace the capacitors on the new board after you verify everything still works.

I didn't take a picture of the originals but this is what they say:
1000uf 35V GF 105 degrees C P709 vent (those three were glued together on the original power supply. Then the other single one says: 2200uf 16V GF 105 degrees C P727 vent.

He also put in a part # NTE6083 a Schottky Barrier Rectifier?

Hope these pics help.

Ugh, clearly he doesn't know how to use flux cleaner either!

It looks like the new capacitors are fine. Which is unfortunate because something else has likely blown.

Perhaps the new rectifier he put in couldn't handle the load and blew up?


Edit: Why does the device on the smaller heatsink have 3 legs sticking up in the air??

[kaboom]

Re: Need advice for power problem

This is all I have to say.



What a HACK.



Those caps got hot- see how the sleeve has 'reshrunk' on some of them?

Did they blow out the seal on the bottom or did he put them in crooked? I'm thinking the former, since I see what looks like foil underneath one of 'em.

What the hell are those? Two schottkeys piggybacked? I love the "put the leads into the nearest holes" trick. Also looks like the pinning/polarity is wrong.

I'll bet he thought, "No need to replace those Lelons."

Looking at the back, I see at least one diode with no solder on it.

"Lamont, you BIG DUMMY." This guy shouldn't be changing light bulbs.

If you see genius again, show him these two images.

[shovenose]

Re: Need advice for power problem

Either he did a really crap job installing those caps, or the bungs burst!

[lucyboop]

Re: Need advice for power problem

"Edit: Why does the device on the smaller heatsink have 3 legs sticking up in the air??"

Yes, he used the original to piggy back the new one. I've been taken many times in my life but this one really pisses me off!

He also changed some little diode too. No matter what he did it still has no picture and chirps like a bird.

[shovenose]

Re: Need advice for power problem

"Edit: Why does the device on the smaller heatsink have 3 legs sticking up in the air??"

Yes, he used the original to piggy back the new one. I've been taken many times in my life but this one really pisses me off!

Could we please have a better picture of that device and how he rigged it up?

[kaboom]

Re: Need advice for power problem

No matter what he did it still has no picture and chirps like a bird.

Because the shorted caps are still in there.

There are plenty of joints that need to be resoldered.

Shovey, the new diode is a single unit, the old one was a dual common cathode. I've traced it and it looks like it's the right way around.

It's also got a PFC booster. Two main supplies, one with the big transformer. The second (small transformer) is either standby and/or minor rails.

[lucyboop]

Re: Need advice for power problem

thanks for all of the advice guys! After a couple of weeks of searching the Internet and having orders cancelled on me, I finally found a company who had a power supply. It actually had Nichicon capacitors in it. I installed it and it works like a charm. In the meantime I bought a brand new HDTV and I'm happy with it.