Home Theater Forum and Systems banner

PT-53WX54J convergence repair botched, help?

1383 Views 2 Replies 3 Participants Last post by  Lumen
Hello my new friends! I was wondering if any of you could be of assistance. There hasn't been a thread about one of these ancient TV's in a while so I figured I may as well start my own. I did some research beforehand which is what led me to using information on this forum to attempt this repair myself. I'm only 23 but have been a techie my whole life and have a fair amount of sense and some experience with electronics so I figured I was up to it. I know it's probably time for this TV to bite the dust anyway but we can't afford a replacement right now, and after replacing some bad caps on a LCD monitor I found on the side of the road I was in the mood for more soldering practice anyway.

My moms Panasonic has messed up convergence. Looks like it's just the green that's out of wack - warped up from the bottom, but there's kind of a horizontal line across the middle too. Whatever it was I didn't take a picture and now it's too late. But I'll get to that in a second. After reading about all the different types of symptoms I'm pretty sure it's a typical burned out convergence chip/resistors.

Against the recommendation of people here, I ordered new IC's off ebay, from a US vendor with very good feedback on the item and in general. The set originally had STK-392-110's but I keep reading that 150's are better so that's what I got. The seller claimed they were real Sanyos. I don't think this was where I went wrong though. You see I haven't ordered any resistors yet. I was going to wait until I got the board out and checked up close to see which ones were burnt out.

While searching for more info today, I found some blog with a guy doing the same repair, and he couldn't get the HV cables disconnected, so he just left them connected and flipped the whole board assembly on it's side inside the TV and did the soldering on a vertical surface. I was nervous about disconnecting the flyback anyway even though I bought a used high voltage probe/meter specifically to make sure it was safe (and left the set unplugged for 2 days). I stupidly followed this persons advice and did it his way. (It turns out this persons blog is actually posted on this site as an example of BAD advice... lol). The TV is on the floor, so I was laying on my side, making the work kind of tricky and uncomfortable. I wish I would have realize I could just twist the connectors to pull them out, then remove the board fully and work on it horizontally in a more comfortable position, but oh well. Furthermore this fellow did not find any burned out resistors on his set, so he only replaced the IC's. I didn't find any burned out resistors either, so I went ahead and replaced the IC's only, even though I read here that they usually burn out together. I hooked all the cables back up and as soon as I turned it on, resistor R7012 burned out, and no image came on the screen.

I had a feeling this might happen, so I wasn't too upset. But I do have a few questions. Should I only replace just the resistor that burned out, or should I replace all of them? Also, did I ruin the new IC's by putting them in with bad (but not visibly bad until now apparently) resistors? Also, I did kind of a rough job desoldering the first IC, I burned the board a little bit, and some of the pads looked kind of rough and although I didn't think I cracked any traces, I left some scratches around the area. Does the current symptom of the screen not lighting up at all sound consistent with bad resistors, or did I ruin it some other way? Even though I tried to check for damage with a magnifying glass when I was done, I will search again tomorrow when I desolder the bad resistor/s.

Any advice I can get will be appreciated!
See less See more
1 - 3 of 3 Posts
I would only replace the bad resistors. No reason to do more. You very well could have blown the ICs with bad resistors, but there is no way to know. I would take the chips out and fire it up and it should run with no convergence correction just to see if you damaged something else. Check all of the power supplies to be sure that they are running.
Reworking surface-mount ICs can be tricky, especially when pin pitch drops below 0.65mm. Too much heat, and the pads lift off the PCB substrate. Physical stress such as bending can break delicate junctures between pads and traces. To be sure, ring these out with an ohmmeter rather than relying on visual inspection with a magnifying glass. A special microscope made for this purpose is best but can be cost-prohibitive for casual use.

Sent from my iPad using HTShack
1 - 3 of 3 Posts
This is an older thread, you may not receive a response, and could be reviving an old thread. Please consider creating a new thread.