Based on the experiences of the valiant pioneers, I finally decided to try to service my 42PF7320A which had the, all too common, half black screen problem.
My 42PF7320A was purchased new at Sams club in November of 2005 for $1900 + tax = $2150. Final assembly was done in Mexico. I believe the manufacturing date was some time in the spring of 2005. The first time I ever saw a half black screen was in August of 2007, so the warranty was expired. The problem would generally clear on its own, and was fairly rare. Lately, it has been somewhat more common, but I could still pretty much live with it. As a rule, the TV is only used a couple of hours a day. It would typically be OK for at least an hour. Then the bottom half might flash black or rainbow. I could get the full picture back by tapping on the right rear of the case, which would almost always buy me at least a half hour. Since its just the wife and me, the situation was almost bearable. I was not willing to spend a lot of money on service, or to have it in a shop for weeks since I can get a new 47" LCD for 1/2 of what I had payed for this. However, I was also reluctant to do anything drastic and create an 85 lb paperweight that I had payed over $2000 for.
The reports of successful, no cost service, over the last few month got me to the point where I took a crack at it on Thursday.
I used the following tools:
T-10 Torx bit
T-25 Torx bit
Fully charged drill driver that could be set for a very low torque.
Philips screw drivers 1-3
1/4" flat blade screw driver.
Rigid blocks(4" minimum thickness) to support the TV face down.
ESD wrist strap.
My set used the Philips stand, as opposed to a wall-mount.
I moved the set onto a sturdy table with the outside edges of the frame setting on the blocks and rotated it down so that the center and top of the outside edges were also resting on the blocks.
I used a #3 Philips to remove the (2) screws that locked the stand to the back of the set. Then I removed the caps from the tops of the stand, and slid the stand off of the studs. Then I used the T-25 Torx bit to remove all 4 studs. The lower pair had supported the stand. The upper pair were not in use. I presume they are used my some wall-mount hardware.
Then I started removing the screws that secure the main back panel using the T-10 Torx bit in my drill driver. I had some cups out to keep the hardware organized. I believe there were 30 longer screws on the perimeter of the panel. I believe there were about 17 slightly shorter sheet metal screws in the field of the panel. Note: 2 of the screws were pointed up on the indented section of the panel. The panel was finally free, and I gently removed it, taking care not to touch anything inside the TV during the process.
You don't want any power on the set while you are working on it, but you still want it grounded. I don't have an ESD safe workstation that could accommodate the TV, so I plugged the TV power cord into a switched power strip plugged into a wall outlet with the power strip switched off when working inside the TV. That way the chassis and neutral were both grounded, but there was no power to the TV. Warning: Even if the TV is turned off, there will be power to some of the standby circuitry, if it is plugged into a live outlet. Then I connected my ESD wrist strap clip to the chassis to keep me discharged.
Unlike Croaker_f2 who worked on this problem, there was no padding under the boards in my TV.
Sorry! I forgot to break out the camera.
I checked out the 2 Video drive cards that are on the left side when viewed from the rear, They are essentially mirror images. They each had 2 connectors which connected them to the mother board and one connector that joined them. I had to remove 2 screws that locked down a metal frame that ran along the top of the unit, since it blocked the screw on the upper card. Once the screws were out, I could slide the frame up a little and its tabs came out of chassis. I moved it as little as possible to avoid strain on the cables attached to it.
Then I removed the single screw from each of the drive cards using a #1 or #2 Philips screw driver. On my set, each drive card had a larger black connector with a latch that had to be lifted up to release it, and a smaller white connector that also connected it to the mother board. I tried to avoid placing any unnecessary strain on the connectors joining the drive cards or on the cables and connectors that connect the drivers to the plasma screen. With the latch held up, I used the 1/4" flat blade screw driver to VERY GENTLY nudge the black connectors apart. I worked the 2 boards in very small increments so that I could keep the boards in line and not place any unnecessary strain on the connector between them. I got the drive cards fully unplugged from the mother board. Then I pushed them back onto the mother board keeping the pressure as even as possible on the 2 boards until they were firmly seated. Then I reinstalled the screws that locked the driver cards to the chassis studs.
Again, being as gentle as possible, I slid the tabs on the upper frame back into the chassis and installed the 2 screws that held it in place.
Now I could remove the power plug and my ESD strap clip, and reinstall the back panel. Then it was just a mater of reinstalling all the panel screws and all the other hardware.
I stood the unit back up on its stand and placed it back on the cabinet it normally sits on. I reconnected the antenna and power cord and plugged the power cord directly into a wall outlet.
Next came the moment of truth. I turned on the TV. The full screen displayed an image! Then I tried a tap test. The image was stable!
The TV has only been on for few hours since I did the work, but I am quite optimistic. Before I did the work, the bottom half would would go on and off with very gentle tapping. Now it seems stable.
This may not be permanent, but maybe I have bought myself a few years. Here's hoping. All I have invested is a little time.
I do like the set. It is a good size for the room, and it has something most new sets don't have - Video outout. The Stereo Audio out it provides works with my old receiver to provide reasonable surround sound. If I got a new TV, I might have to get a new receiver. That would create another problem since new receivers don't have an input compatible with my turntable. No laughing please! My audio gear is long in the tooth, but sounds fine to me. For the record, I do have a CD player (holds 5 CDs), but I have some old classic records I want to be able play. I'm in my early 60s, so my hearing is not as demanding as that of the younger crowd.
Anyway, I thought I would share my experience. Again my thanks to the pioneers who shared their experiences and gave me the courage to give this a try.