Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

[retiredcaps]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

did you mean the two little brown caps near the one big brown cap?

Those and the ones underneath that big heat shield.

If they are Capxon, replace them all. The main filter capacitor (biggest one) rarely, but not never, fails.

[Boregy]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

Thanks for the input!

did you mean the two little brown caps near the one big brown cap?

image 73 is of one of the smaller browns, image 74 is of one of the medium browns under the heatsink.

[retiredcaps]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

here's the rest. I suspect 2 caps are bad, maybe more.

You definitely have at least 2 caps. The Capxon cap just right of the fuse KOAC and Capxon underneath the heatsink.

Capxon has a poor reputation here so most will automatically replace any Capxon cap.

What brand is the brown caps?

Replace all the Capxon capacitors with high quality low ESR caps from this list.

https://www.badcaps.net/forum/showthread.php?t=2280

Members here like digikey.com and order Pansonic FM caps for replacements. You can also support this site by choosing Rubycon and/or Samxon caps.

[Boregy]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

here's the rest. I suspect 2 caps are bad, maybe more.

[Boregy]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

Here's some pics, more to come.

[Boregy]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

Nevermind, I got it off finally. It was the 2 screwed on the VGA plug that I didn't realize I needed to get off.

Pictures to follow.

[Boregy]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

Guys I think I have the same problem.

I want to take a look inside, but I'm having some trouble getting the metal cage surrounding the electronics off. Any tips?

Thank you.

[jetadm123]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

I noticed that cap prices have increased quite a bit in the last month. Also, I noticed digikey and mouser dropped their discount price for qty=> 10. The new threshold is 50 caps.

Yes, Digikey has dropped their qty=10 discount. And it was a great discount while it lasted. Unfortunately, I don't do enough repairs to justify a purchase of 50 caps per value at once. However, I started to look at the UCC KY series caps at digikey and they still offer the qty=10 discount. The specs aren't as good as the Pany FM series, but still acceptable. Digikey is still hard to beat if you're just buying a few caps and use the USPS first class shipping option.

[retiredcaps]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

If you order Panasonic FM/FC series caps from digikey.com, it should run you $11-$12, including shipping.

I noticed that cap prices have increased quite a bit in the last month. Also, I noticed digikey and mouser dropped their discount price for qty=> 10. The new threshold is 50 caps.

[jetadm123]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

I have had the monitor in an upright position since I took the back off. I still have not had the flicker occur again. I did try to briefly hit the power supply with a hair dryer, but did have any luck reproducing the flicker. I'll try again later with a more powerful hair dryer.

Another thing that leads me to believe the problem is related to the capacitors is that there is a loud, high pitched whine when the power is plugged in, but when the monitor is off. It sounds like a capacitor continuously charging. When the monitor is on, it's still there, but at a much lower volume.

Thank you all for helping!

Looks like they're using some good quality caps. Even good quality caps can go bad working under adverse conditions. They look like UCC KY series caps. Yes, bad caps can cause a whine. Minus the large 450V cap I count something like 9 smaller caps. If you order Panasonic FM/FC series caps from digikey.com, it should run you $11-$12, including shipping.

[retiredcaps]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

I'm beginning to think that the 1000uF cap near the wiring harnesses is the culprit. It's not bulging in the center like you would normally see, but it appears to be bulging around the edges ever so slightly. I'm not sure if you can tell in the picture, but in person the top is not flat like the rest of the caps.

Bad caps can cause flicker. I can't tell in the pictures, but caps do not have to be bulging to be bad. They can be out of uF tolerance and/or have high ESR (ohms).

[Minathevi]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

Without the backing on the monitor, I still get the same amount of flicker so it's not a heat issue for me. I'm beginning to think that the 1000uF cap near the wiring harnesses is the culprit. It's not bulging in the center like you would normally see, but it appears to be bulging around the edges ever so slightly. I'm not sure if you can tell in the picture, but in person the top is not flat like the rest of the caps.

In regards to JoseJX's monitor, is it possible that there is some sort of intermittent grounding going on when the backing is in place? Just a thought because there are several points in which the backing comes close to all of the boards.

[JoseJX]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

Something to try,
With the monitor apart try to position the LCD as it would normally be positioned. I have found problems with ccfl wiring may take much longer to present with the panel laying flat.In its normal position heat will rise and cause a problem to occur much quicker.
Al.

I have had the monitor in an upright position since I took the back off. I still have not had the flicker occur again. I did try to briefly hit the power supply with a hair dryer, but did have any luck reproducing the flicker. I'll try again later with a more powerful hair dryer.

Another thing that leads me to believe the problem is related to the capacitors is that there is a loud, high pitched whine when the power is plugged in, but when the monitor is off. It sounds like a capacitor continuously charging. When the monitor is on, it's still there, but at a much lower volume.

Thank you all for helping!

[jetadm123]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

On my board the fuses are also intact. The PWM you mentioned is P/N 4419 BA6116 and it also appears to be an Alpha Omega Semiconductor chip. The solder joints on the Power Supply board look good. I just cleaned up the residual flux. As far as the wiring harness is concerned, I wouldn't have the slightest clue where to begin. When I get a chance I'll just take readings on all of them in sequence.

Unfortunately, this is one of those power supplies they don't want you to work on as evident by the riveted heatsink covers and that the wiring harness has no silkscreened listing of what each wire does.

More importantly, in post #55, JoseJX reports that since removing the cover, he has not experienced any flicker. Are you encountering the same results?

[Minathevi]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

On my board the fuses are also intact. The PWM you mentioned is P/N 4419 BA6116 and it also appears to be an Alpha Omega Semiconductor chip. The solder joints on the Power Supply board look good. I just cleaned up the residual flux. As far as the wiring harness is concerned, I wouldn't have the slightest clue where to begin. When I get a chance I'll just take readings on all of them in sequence.

[jetadm123]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

Another member, Minathevi, also entered this thread with the same model model monitor. Therefore, this can add some confusion because members are not sure who's talking to who and may wind up perfoming unnecessay tests.

AP4419 spec found here:

http://www.alldatasheet.com/view.jsp?Searchword=AP4419

Definitely sounds like a heat related problem, since taking off the cover allows more air flow past the board and reduces heat build up.

The fuse and harness measurement tests were really meant more for Minathevi, since it looks like you're getting an image without flicker, which means the voltages are probably ok.

Possible problem could be bad caps because those heatsink covers really contain the heat and basically "cook" the caps along with the other components.

Another problem could be a bad solder joint. As the the board heats up, it will flex a little and that could cause the joint to open up. Try looking for bad joints, especially around the transformers and touch them up with your soldering iron and fresh solder.

Also, I've seen flickering caused by bad caps on the the logic board. Because of the smaller footprint on the logic board, the manufacturer will "shove" large cap values into a physically small can, which over time dries out. Try heating up the logic board with your blow dryer to see if you can recreate the flickering problem.

I reread your initial description of the symptoms and please disregard my last suggestion concerning the logic card.

[jetadm123]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

On my monitor, the fuses are all intact. That chip is marked with "4419 BA6515" and a logo that could be "Alpha and Omega Semiconductor", but it's hard to make out on my chip. A&O does have a part with a 4419 marking, it's a P-FET and it's in an 8 pin package like this part. I haven't been able to find out more.

What do you want us to measure exactly on the wiring harness?

As an aside, I haven't had any flicker since I pulled the monitor apart. I did also pull and re-plug the CFL wiring and made sure that all of the wiring harnesses were solidly connected.

Another member, Minathevi, also entered this thread with the same model model monitor. Therefore, this can add some confusion because members are not sure who's talking to who and may wind up perfoming unnecessay tests.

AP4419 spec found here:

http://www.alldatasheet.com/view.jsp?Searchword=AP4419

Definitely sounds like a heat related problem, since taking off the cover allows more air flow past the board and reduces heat build up.

The fuse and harness measurement tests were really meant more for Minathevi, since it looks like you're getting an image without flicker, which means the voltages are probably ok.

Possible problem could be bad caps because those heatsink covers really contain the heat and basically "cook" the caps along with the other components.

Another problem could be a bad solder joint. As the the board heats up, it will flex a little and that could cause the joint to open up. Try looking for bad joints, especially around the transformers and touch them up with your soldering iron and fresh solder.

Also, I've seen flickering caused by bad caps on the the logic board. Because of the smaller footprint on the logic board, the manufacturer will "shove" large cap values into a physically small can, which over time dries out. Try heating up the logic board with your blow dryer to see if you can recreate the flickering problem.

[alexanna]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

As an aside, I haven't had any flicker since I pulled the monitor apart. I did also pull and re-plug the CFL wiring and made sure that all of the wiring harnesses were solidly connected.

Something to try,
With the monitor apart try to position the LCD as it would normally be positioned. I have found problems with ccfl wiring may take much longer to present with the panel laying flat.In its normal position heat will rise and cause a problem to occur much quicker.
Al.

[JoseJX]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

On my monitor, the fuses are all intact. That chip is marked with "4419 BA6515" and a logo that could be "Alpha and Omega Semiconductor", but it's hard to make out on my chip. A&O does have a part with a 4419 marking, it's a P-FET and it's in an 8 pin package like this part. I haven't been able to find out more.

What do you want us to measure exactly on the wiring harness?

As an aside, I haven't had any flicker since I pulled the monitor apart. I did also pull and re-plug the CFL wiring and made sure that all of the wiring harnesses were solidly connected.

[jetadm123]

Re: Westinghouse L2410NM 24" LCD power goes on and off, blue light flickers

Delivered

I've marked in red what look to be 3 fuses, marked FZX? Can you check those for continuity? If they check out ok, have you tried measuring the voltages at the two wiring harnesses? It doesn't look like any of the wiring is labled with what each wire is for.

I also marked in yellow a 8-pin PWM chip. Can you read off the part number?

Flickering does sound like a bad cap problem and a cap doesn't have to bulge to be bad. Also a bad CCFL lamp/wiring can cause that problem.