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Electronics Repair (sci.electronics.repair) Discussion of repairing electronic equipment. Topics include requests for assistance, where to obtain servicing information and parts, techniques for diagnosis and repair, and annecdotes about success, failures and problems. |
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Mitsubishi TV PIP question
I have a Mitsu CK-35702...probably 10-12 years old. In the last two
weeks the set has started showing signs of what appears to be the classic PIP failure (vertical flicker that subsides after running the set a couple of hours and a darkening screen). My question is whether this set would have the 930B522 PIP board....and secondly, if so, is it particularly difficult to get it out? Living in the woods of southern Vermont, I guess it would be possible to ship the board somewhere for repair (while doing a temporary bypass), but the chance of getting a qualified tech in this area would be quite slim. The size of the TV precludes my sending it out for repair. If, in fact, the PIP board is a 930B522, I'd prefer to order parts prior to pulling things apart. Thanks for any insights. Alan |
#2
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Mitsubishi TV PIP question
My question is whether this set would have the 930B522 PIP
board....and secondly, if so, is it particularly difficult to get it out? It's got the 930B552 PIP board which is the same used on the smaller models and is the one that causes trouble. It unplugs easily from the main board. If you want to replace the surface mount caps it takes about 13 and a good amount of soldering skill to avoid damaging the board. Good luck. Ron |
#3
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Mitsubishi TV PIP question
Thanks alot for the info, Ron.
My main efforts will be to construct a temporary bypass while I decide whether to find someplace outside to rebuild the board or tackle it myself. There used to be places that did this sort of thing. As long as I know the board type, I'm sure I can handle the bypass OK. I appreciate your help. Alan On 12 Jun 2004 15:56:16 GMT, ospam (RonKZ650) wrote: My question is whether this set would have the 930B522 PIP board....and secondly, if so, is it particularly difficult to get it out? It's got the 930B552 PIP board which is the same used on the smaller models and is the one that causes trouble. It unplugs easily from the main board. If you want to replace the surface mount caps it takes about 13 and a good amount of soldering skill to avoid damaging the board. Good luck. Ron |
#4
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Mitsubishi TV PIP question
If you intend to contruct the bypass yourself, why not just fix it instead.
While I'd do it for you I would have to charge you. If you can solder it's an option, and anyhting is better than what they charge for a new one.If you think you want to do it, I'll give ya a couple pointers. Twist or cut the old caps off, do not attempt to unsolder them, do them value by value. Just in case "**** happens" I'd recommend you scan it if you have a flatbed before removing any caps. If you get interrupted and lose track, or if the polarity markings are gone or obscured on the board, having am image, even on the computer screen can save your butt. Once a cap is out, remove all solder and the old leads with solder wick, then let the wick and your iron land for a second on the board, it'll heat it up and you'll smell that crap evaporating out of it. This stuff is corrosive so the less of it in there the better. Don't stay there too long or you'll damage the board. Wipe it off with a Qtip dipped in acetone. Then apply new solder to the pads. Don't bother using surface mount replacements, it's simply not nessecary nor is it a good idea. If you wanted me to do it I'd have to charge you about $60. If there is something that makes the board unrepairable I'd probably send you a good one for $100, but if you wanted yours rebuilt with SMD caps I'd have to charge about twice the $60. SMDs are simply not worth it when you have that much room, also they are pretty crappy caps to start with, regular lytics out perform them, and if you really wanted to get fancy you could use tantalums. I wonder if anyone out there has done this and maybe can actually say there is a picture improvement of any kind with tantalums. No matter what kind you want you should take inventory and order them all in advance. Just put the module back in (tape up the ground wire), put all but four of the screws in a baggie and you won't need the bypass. Wait until you have everything you need right there, until then watch it the way it is. Put the back on for now. Don't run a TV in your home with the back off. Anyway, I know you didn't really say you wanted to do it yourself, but you did say that you would do the bypass, that leads me to believe you can at least solder. That's why I figured I'd throw this at you. Basically you could "bypass" it with a fixed module. JURB |
#5
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Mitsubishi TV PIP question
Also, when inspecting the PIP PCB make sure that the material from the caps
did not eat thru some of the very thin traces on the surface of the board. This is a very common occurrence and can be aggravating to repair. Also, while in the set you may want to ESR the rest of the caps in the set and replace any that are questionable. "JURB6006" wrote in message ... If you intend to contruct the bypass yourself, why not just fix it instead. While I'd do it for you I would have to charge you. If you can solder it's an option, and anyhting is better than what they charge for a new one.If you think you want to do it, I'll give ya a couple pointers. Twist or cut the old caps off, do not attempt to unsolder them, do them value by value. Just in case "**** happens" I'd recommend you scan it if you have a flatbed before removing any caps. If you get interrupted and lose track, or if the polarity markings are gone or obscured on the board, having am image, even on the computer screen can save your butt. Once a cap is out, remove all solder and the old leads with solder wick, then let the wick and your iron land for a second on the board, it'll heat it up and you'll smell that crap evaporating out of it. This stuff is corrosive so the less of it in there the better. Don't stay there too long or you'll damage the board. Wipe it off with a Qtip dipped in acetone. Then apply new solder to the pads. Don't bother using surface mount replacements, it's simply not nessecary nor is it a good idea. If you wanted me to do it I'd have to charge you about $60. If there is something that makes the board unrepairable I'd probably send you a good one for $100, but if you wanted yours rebuilt with SMD caps I'd have to charge about twice the $60. SMDs are simply not worth it when you have that much room, also they are pretty crappy caps to start with, regular lytics out perform them, and if you really wanted to get fancy you could use tantalums. I wonder if anyone out there has done this and maybe can actually say there is a picture improvement of any kind with tantalums. No matter what kind you want you should take inventory and order them all in advance. Just put the module back in (tape up the ground wire), put all but four of the screws in a baggie and you won't need the bypass. Wait until you have everything you need right there, until then watch it the way it is. Put the back on for now. Don't run a TV in your home with the back off. Anyway, I know you didn't really say you wanted to do it yourself, but you did say that you would do the bypass, that leads me to believe you can at least solder. That's why I figured I'd throw this at you. Basically you could "bypass" it with a fixed module. JURB |
#6
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Mitsubishi TV PIP question
"Art" wrote in message ... Also, when inspecting the PIP PCB make sure that the material from the caps did not eat thru some of the very thin traces on the surface of the board. This is a very common occurrence and can be aggravating to repair. Also, while in the set you may want to ESR the rest of the caps in the set and replace any that are questionable. I used to always repair these boards, though lately I've come across a couple which had much worse trace rot, those I just bypassed, too much work when there's electrolyte under SMD IC's and such. |
#7
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Mitsubishi TV PIP question
We repair lots of these sets. The rule of thumb we use is if any of the
electrolyte has reached the IC, ditch the board. If it is limited to just around the caps, clean the traces completely, tin the areas that you have to scrape clean, and replace all of the SM caps with radials. Keep in mind that not all of the boards can be easily bypassed. The later versions of that board had a higher input level on the luma line and it has to be adjusted for. The NESDA Ohio site has some useful notes that include the numbers of the boards. FWIW, recently in Florida, most of the boards that we have been seeing recently have been so badly corroded that they are not worth attempting repair. Leonard "James Sweet" wrote in message news:EIRyc.91789$Ly.1916@attbi_s01... "Art" wrote in message ... Also, when inspecting the PIP PCB make sure that the material from the caps did not eat thru some of the very thin traces on the surface of the board. This is a very common occurrence and can be aggravating to repair. Also, while in the set you may want to ESR the rest of the caps in the set and replace any that are questionable. I used to always repair these boards, though lately I've come across a couple which had much worse trace rot, those I just bypassed, too much work when there's electrolyte under SMD IC's and such. |
#9
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Mitsubishi TV PIP question
Do I understand correctly that once the old caps are removed from the
board, it can be inserted and used as a temporary bypass? The set won't get a picture at all if you remove the caps and reinstall the board. You either need to repair the board or do the bypass of the board. Mitubishi at one time I believe had a plug in bypass board available to eliminate the entire PIP board. I always just repair the board. At least in your case, since you still have a picture, the chances of electrolyte out of the caps doing major damage to the board is slim. Ron |
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