Another TX-42F430S fixed by replacing the 470uf cap, thanks all! To try and give back a bit I'll tell my story for any who care to read it.
The trouble started one night when the screen went crazy and showed what looked like a messed up version of the menu on the screen. Like I'd done many times before I pulled the power cord from the TV and waited a few seconds after the power light on the front went out before plugging it back on. This time the screen never came on and the LED on the front stayed orange instead of turning blue. I checked online to see if there was anything I could do and I found my way to this thread.
The first thing I tried was the firmware replacement. I'm not sure if it ever took, but I was at least able to get the USB drive to light up a couple times by following these steps:
- plug in the power
- press the power button once
- hold the power button again for 15 seconds (I'm assuming this triggered a reset of some sort
- wait a few seconds and watch the drive like up a few times
This never seemed to have any impact with any of the firmware versions posted here, even when I left it sitting for a long time before restarting. This left more complicated solutions which I wasn't comfortable tackling on my own, so I called a local TV repair shop. The repairman said he thought it was the power supply and would come out the next morning. Still suspecting the capacitor, I decided to try out the blow dryer capacitor test before he showed up. I tried pointing the blow dryer at the capacitor shown in the pictures from this thread from about 6 inches away and plugged it in with a video source plugged into the HDMI 1 port, but nothing happened. I'm not sure if I didn't get it hot enough, but I was worried I'd fry the electronics if that wasn't the problem so I gave up.
When the repairman showed up he checked the power source and said it was perfect. He was surprised to learn that the set was about 7 years old. He said there wasn't much else he could do beyond replacing the motherboard, which would have been too expensive, so I asked him if he could try replacing the capacitor discussed on here. He said he had time and I figured I had nothing to loose so we proceeded. He tried touching the capacitor I pointed out and said it was hot, which he said was a sign it had gone bad. He said sometimes they'll bulge too when they go bad, but that they might do neither if they're bad. He checked some of the other capacitors too (mentioned in other posts) but said they all felt fine. I believe he replaced it with a 25V or 35V, since I told him people recommended increasing the voltage to avoid it failing again. It took him a couple minutes, but once he was done we plugged it up and within a few seconds we could see a white glow through the back (it was set facing down on a bed). We put it all back together again and plugged up the video source and sure enough it worked like a charm.
The TV's been going strong for the last week, as if nothing ever happened. It ended up costing me $150 (maybe a bit high for some, but in LA I figured it was fair), but saved me much more, and it looks like the TV should keep on going strong.
On a bit of an aside, the repairman said he'd be in the business for 30 years and that he wouldn't be surprised if it was his last year with how the market was moving. I guess cheaper TVs with expensive circuit boards which people don't see as economical to replace have been taking over and making it harder to keep a repair business going. I know many people here are just fixing it themselves, but I appreciate the information in this thread making it possible for me to support the dying art of TV repair. Thanks!