Philips Plasma TV - Half Black Screen - Page 3

Nothing to see here, head to my next next post for pic!

Okay, so I opened up the TV (tip--I used an ice cube tray to keep the screws straight. Also, before removing any screws, there were some unused screw holes for mounting brackets etc, so I put tape over those so I wouldn't be tempted to fill them later.)

I should now have bypassed the spam url filter, so I can post the pic next!

I followed the advice in this thread and fixed the half black screen problem! Here's a pic of the open TV for others since that's the only thing missing from this thread. I put a red and orange screwdriver in the photo for reference points. The top of this picture is the left side of the tv as you look into the back of it, glass side down.

The orange screwdriver handle is pointing to the black connector where the lower Y board connects to the main board, and the red handle is pointing to the upper Y board connection. Additionally the upper and lower boards connect to each other with a small white clip between them (it's above and between the black bar connectors.) To avoid breaking it, we disconnected the white connector that joins the top & lower boards before disconnecting them from the motherboard. There is a tiny tab that you grab to flip the white connector open like a little treasure chest.

Across the top of the picture are 6 brown hinged connectors, or 3 per board. Just pop those up. In between each of those there's a screw to remove, so 5 screws. The rubber padding under the boards is pretty sticky, so before you try to separate the boards from the black connectors gently separate the boards from the padding underneath. Then use a very thin flat screwdriver to wiggle the black connectors apart, & pulling the board gently. There is not a clasp to lock those black connectors together, but there are 3 tiny bumps that prevent it from coming apart. You do need to make sure the board is not stuck on that stick rubber underneath or it can't slide at all.

After removing the boards, at the suggestion of others ITT, I peeled off one layer of the padding leaving several still behind. Only my upper board had been a problem but I figured I might as well do both now rather than do this all again. When reconnecting the boards into the motherboard, make sure it's a tight connection as you replace the 5 screws.

Need clearer picture -- and what exactly FIXED the problem ??

I reported a successful repair of my 42PF732A on 8-29-2009 in my post http://www.avsforum.com/avs-vb/showt...0#post17083910
The problem started to re-appear in June or July of this year. At first it was very rare and would just flash for a few seconds. It gradually became worse. Lately, sometimes the bottom would go black, occasionally the top would go black, and even more rarely it would go completely black. Tapping on the right side, as viewed form the front would cause the problem to come and go.
I finally broke down and repeated the re-seating of the 2 driver cards. I used the same procedure I did before.

In my case, a Mexico assembled 42PF7320A dated September 2005, there is no packing material behind the 2 drive cards. There is a connector between them, and each is connected to the main board by 2 connectors, a black one with a lift up latch and a white one with no latch. I did not separate the 2 cards. I carefully worked them out together, and re-seated them. Actually I did that twice.

When I got it set back up, tapping had no effect. The picture was solid. It looks like I have bought myself some more time.
If I can continue to get a couple of years out of a re-seating, I guess I'll keep on doing it. However, I will not spend any money on the set. I just cannot justify that to myself, considering the current cost of a unit of similar size and features.

If these units did not use matched connector parts, I would almost suspect metal migration. I used to work as a test engineer for Western Electric. The Bell Labs metallurgists who supported our Bell Labs designers were always worried about components getting inserted in sockets with different plating. We were required to only put Gold leaded parts in Gold plated sockets and Tin leaded parts in Tin plated sockets. When they got mixed, there was fear of metal migration, when low currents passed through the connections for a long time. Eventually, the quality of the connection would deteriorate. The contamination layer was extremely thin, and re-seating would temporarily solve it, but that was not an acceptable repair. The factory was required to replace both the socket and the component with parts that had the same finish.
I do suspect that the plating on one of the connector sets is of poor quality. Since the connectors seem to be used in multiple versions of the set, that would explain why the problem seems to exist in different versions of the Philips TVs that were probably assembled in different countries. I believe Sam's Club had units from Mexico and Europe when I got mine. Actually, the final assembly point may not be relevant since all of the modules may have been assembled in the same plant and both of the connector types probably came from single suppliers.

FOLLOW-UP
It has been a few days, and all is well.
I am optimistic that I have bought myself a year+ of freedom from the 1/2 black screen. It took about 2 years for the problem to originally show itself on extremely rare occasions. I had the set for almost 4 years when it got bad enough that I did the first re-seat of the drive cards. That got me well over a year without any problems, and 2 years until it got bad enough that I did the second re-seat. I guess I can live with re-seating the drive boards at one year plus intervals until the set actally dies.

I just picked up this set from someone throwing it out. I took it home and it has the 1/2 dark problem, but the bottom half is not completely black. It has some pixels at the bottom, like a sound spectrum. I opened it and and tried to reseat the bottom Y board, but the pic is still the same. I took out the lower board and saw the bottom midde pin is short. Is tis supposed to be this way? If trying to decide if I am going to replace the board or not since the tv was free.

I have never taken a look at the length of the connector pins, but I cannot think of any reason why one would be shorter than the rest for a connector that should only be plugged and unplugged when there is no power on the TV. Short pins are normally only on a connector that is plugged in LIVE, when it is important that the short pins signal be the last one to get connected.
I would suspect that the pin is pushed back in the connector, but should not be. There should be an identical connector on the upper board. If that pin is not also SHORT, I would say that you have evidence that there is a problem with the connector on the lower board.