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#1
02-02-2012, 01:58 AM
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Panasonic with barcode picture
Older plasma TH50PHD3 set internally, sold as a Toshiba 50HP81. About 8 years old I think. Got it on a trade in for a new bigger set. It used to start up with a multi colored barcode picture for a few minutes, then slowly the picture would come in as the bars got fewer and be fine until the next time it started up cold. See enclosed picture. After a few months it got progressively worse until that's all it did, steady barcode picture. After leaving it on for an hour, it finally went into shutdown. Replaced the D logic board. Fires up again, but the barcode picture is steady now, normal picture never comes back. Hate to spend much more on it, but it made a great picture when it worked. First time it had any problems. Any ideas on what other panel it might be?
Thanks Dan 
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#3
02-02-2012, 09:45 PM
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Wow, that's interesting. I assume you mean in the power supply. Haven't worked on any of the flat panel sets, so not familiar with that cause/effect. From my old NTSC days, bad caps would cause hum bars or wavy video, or just flat shut down the power supply. I'll have to check that out. Thanks! Dan
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#4
02-03-2012, 10:08 AM
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I would check the processing/video input board. This could also be a software problem. Westinghouse sets and Phillips sets tend to do this when their software crashes.
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#5
02-03-2012, 10:49 AM
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Doubtful if it's power supply. Main board or driver(digital) board. Sounds like a bad solder joint. Take the butt end of a screwdriver and gently push on the boards while its having the issue and see if anything improves or changes. Please be careful around the power supply and y and z boards. nasty shock hazard.
__________________
"It's a mad mad mad mad world" !! http://www.youtube.com/user/mwstaton64?feature=mhee
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#6
02-03-2012, 10:29 PM
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Thanks for all the suggestions. Grew up in my dad's TV shop, learned about getting zapped the hard way! I did the wiggle poke around a bit once before to see if there was a loose connector or wire, but I'll give it a more thorough check. Found the factory service manual for it on line, had a lot of detail on the theory, but was missing the pages for the skiz and block diagrams. Kind of hard to figure out which boards actually sync up all the timing, which was what I figured was a logical starting point. Agree about the cold solder joints. Reminds me of the cold spots on the little PC boards they used to use on the CRT's. The heater pins would go cold over the years. Set would come on, warm up, heaters would go off, after 5 minutes or so they would cool down and reconnect, picture would slowly come back. Old RCA and Magnavox sets from the mid 60's were famous for the video output tube sockets doing that, too. In any case, having fun figuring it all out! Thanks again. Dan
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#7
02-07-2012, 04:18 PM
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another thing to look for (and push on) is a large chip with what appears to have no solder pins. This is a ball grid array chip and loose connections under them is a BIG problem. If you lightly push on it and it works while pushing, there are suggestions on the internet on how to reppair them (baking them in a oven for a given length of time to reflow the solder). I've never done this but a friend of mine repairs HP printers and has done a few that were repaired that way. I know, it sounds CRAZY!
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#8
02-08-2012, 12:20 AM
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Interesting. Never heard of the ball grid until I looked it up. Really like the possible repair solution. My wife would say they named it after me and my projects, half baked ! Remember seeing those big chips in there. It would make sense, too. Acted very much like cold solder joints of old. I'll give that a go this weekend. Great suggestion. Thanks again. Dan
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#9
02-09-2012, 08:49 AM
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#10
02-09-2012, 11:07 AM
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In my experience there is no substitute for having a BGA chip resoldered with the appropriate equipment.
I have an HP TX1000 laptop which had a flaky NVidia GPU (common problem on those and other laptops including other HPs and some Toshibas). It started blacking out the video and losing network connectivity, then eventually got to the point that it would not even show the startup splash screen. The GPU is a BGA chip. I tried a recommendation of cutting out a piece of cardboard to mask the GPU, covering the cardboard in foil and hitting it with a heat gun. The laptop started booting again, but it only lasted about a week before it died again. I sent the motherboard off to a shop in Miami that has the proper BGA resoldering gear (including x-ray to check the soldered connections). It cost $100 plus shipping to have a new GPU soldered in properly. Since I got it back from them in 2010, the laptop has not given me a bit of trouble. The shop I used will only work on specific model laptops.
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#11
02-14-2012, 05:53 PM
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 .... I know it sounds crazy , , BUT , , The "Reflowing" of the solder trick actually saved a PS3 that was destined for the trash heap . It got the "YLOD" , which to gamers of that system is the Yellow Led Of Death , and was well out of warrenty . I went on the net , found a video from someone that had like 5000 people respond back saying it worked for them , so I tried it as a "what have I got to loose" option , and it worked !!!! The "process" was to take out the main board , use a heat gun for a specified amount of time on the offending chip , and then reassemble . The machine ran for 6 or 7 more months of daily use , and was finally replaced with a newer one . Everything ive ever been taught about electronics says that it shouldnt have worked , , massive heat and Chips being a big NO NO , , but , darn it all , it surely did work ! ....... Before I threw anything similar away , I'd at least give that fix a try , if it IS reccomended by those in the know with that particular item ......
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#12
02-16-2012, 05:05 PM
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Ive seen this. Video input (scaler board)
Bad lytics. Small SMD silver can types. Most likely around the processor with the heat sync are the ones bad. Take a can of freeze spray and hit them when warmed up, or a hair dryyer when started up cold. Watch the pic come in clear in all its glory. Panasonic scalers are known for this problem, especially in the Maxent models. Good luck
__________________
Honey, turn on the tv.. I'm cold!
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#13
02-17-2012, 10:15 AM
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Oh yeah, also on the processor reflow the pins. these come loose causing this.
__________________
Honey, turn on the tv.. I'm cold!
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#14
02-18-2012, 12:15 AM
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Of course, because each model laptop requires a special placement and anchor jig so it doesnt warp or bend during a reflow/remount. You only have a certain jigs, and each jig fits its own board. Same deal with xbox360 and PS3s. for PS3, there are 3 known different board mounting configurations so there are 3 different jigs. Gets expensive. I think the standard is 0.14mm of give in any direction. any warp greater than this, the BGA balls will refuse to sit right. I do the reflow thing with an IR rework station now, so I kinda know how this goes. lol. the game systems though are starting to become a major thorn in my side because no matter how much you try those peices of crap keep coming back with the RROD. Hell I even went out of the way and completely replaced the entire GPU on a few, and still got them back within a day or so.
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