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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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Hitachi Ultravision Model 50UX26B Intermittent Power Shut Down
We have a Hitachi Ultravision Model 50UX26B projection TV that was
made in July 1996. Lately it has been shutting itself off at random times. Hitting the power button on the remote usually turns it back on again (you actually need to hit the power button twice; the first time you hear the TV click and the second time it comes on). I don't think it is heat related because it's done it shortly after turning it on sometimes. Other times it will run for a long time without problem. The frequency of the intermittent shut downs has progressively increased from infrequent to several times an hour. Now, we can't power the TV on except occasionally and then it doesn't stay on for long. When we hit the power button the TV would click and the power light would flash on briefly but wouldn't stay on. Does anyone have any ideas what is wrong with our TV and how it can be fixed? We'ev found several other posts to Usenet where people have had the same problem, however, we haven't seen a definitive fix, and no one has followed up to say whether the advised fixes actually worked. Of course, we are hesitant to call a repair service and spend a pile of money only to have the problem continue... Thanks for you help. Angela D'Andrea Austin, Texas |
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Hitachi Ultravision Model 50UX26B Intermittent Power Shut Down
"Angela D'Andrea" wrote in message om... We have a Hitachi Ultravision Model 50UX26B projection TV that was made in July 1996. Lately it has been shutting itself off at random times. Hitting the power button on the remote usually turns it back on again (you actually need to hit the power button twice; the first time you hear the TV click and the second time it comes on). I don't think it is heat related because it's done it shortly after turning it on sometimes. Other times it will run for a long time without problem. The frequency of the intermittent shut downs has progressively increased from infrequent to several times an hour. Now, we can't power the TV on except occasionally and then it doesn't stay on for long. When we hit the power button the TV would click and the power light would flash on briefly but wouldn't stay on. Does anyone have any ideas what is wrong with our TV and how it can be fixed? We'ev found several other posts to Usenet where people have had the same problem, however, we haven't seen a definitive fix, and no one has followed up to say whether the advised fixes actually worked. Of course, we are hesitant to call a repair service and spend a pile of money only to have the problem continue... Thanks for you help. Angela D'Andrea Austin, Texas It's probably just a cracked solder joint in the power supply or horizontal deflection system, if the picture is good I suggest calling a pro unless you have good soldering skills and are able to identify subsystems by looking at the boards to know where to look for the bad joints. The repair should be fairly straightforward for an experienced tech though. |
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Hitachi Ultravision Model 50UX26B Intermittent Power Shut Down
AP63 Chassis
Inspect all electrolytic capacitors for leakage and ESR, resolder the common areas that are problems. Check for defective components and bad solder connections: I601 D936 Q003 I901 I907 R913 I401 T701 T901 L708 and a few dozen more parts. Troubleshooting would narrow it down to the problem area more effectively. Or call a tech that has some experience with these sets. Leonard Caillouet "James Sweet" wrote in message news:JbQtb.169237$ao4.547152@attbi_s51... "Angela D'Andrea" wrote in message om... We have a Hitachi Ultravision Model 50UX26B projection TV that was made in July 1996. Lately it has been shutting itself off at random times. Hitting the power button on the remote usually turns it back on again (you actually need to hit the power button twice; the first time you hear the TV click and the second time it comes on). I don't think it is heat related because it's done it shortly after turning it on sometimes. Other times it will run for a long time without problem. The frequency of the intermittent shut downs has progressively increased from infrequent to several times an hour. Now, we can't power the TV on except occasionally and then it doesn't stay on for long. When we hit the power button the TV would click and the power light would flash on briefly but wouldn't stay on. Does anyone have any ideas what is wrong with our TV and how it can be fixed? We'ev found several other posts to Usenet where people have had the same problem, however, we haven't seen a definitive fix, and no one has followed up to say whether the advised fixes actually worked. Of course, we are hesitant to call a repair service and spend a pile of money only to have the problem continue... Thanks for you help. Angela D'Andrea Austin, Texas It's probably just a cracked solder joint in the power supply or horizontal deflection system, if the picture is good I suggest calling a pro unless you have good soldering skills and are able to identify subsystems by looking at the boards to know where to look for the bad joints. The repair should be fairly straightforward for an experienced tech though. |
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Hitachi Ultravision Model 50UX26B Intermittent Power Shut Down
Angela,
I have the same model manufactured at approximately the same time frame. We have not experienced the problem you describe, but I did have the main power on/off relay go bad so it had to be replaced. I only mention this since it was a pretty easy fix and if you can't find any cold solder joints on the main power board you may want to check the resistance of the relay contacts themselves (mine would stick closed after the set was turned off, but I could imagine that they could just as easily become resistive and have the potential to fail in the manner you describe as well). After dismissing cold solder and checking the other components Leonard cited, I'd look at the relay. Hope you can get this fixed. We still love our set. If you need a schematic, let me know as I think I have the service manual somewhere. Bob "Angela D'Andrea" wrote in message om... We have a Hitachi Ultravision Model 50UX26B projection TV that was made in July 1996. Lately it has been shutting itself off at random times. Hitting the power button on the remote usually turns it back on again (you actually need to hit the power button twice; the first time you hear the TV click and the second time it comes on). Thanks for you help. Angela D'Andrea Austin, Texas |
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I too have the same model television. It seems this is the most common problem for these units. On mine however, you can hear the tv click when you press the power button. I have removed the back and the fuse is still good. In fact the red indicator light (on the circuit board inside tv) comes on when you turn the tv on. Neither the outside indicator light or the screen however come on. Its as if the tv is turning partially on, but not all the way. Any advice would be helpful. I just dont see the reason to take it to a repair shop. I'd rather see if I can get it fixed myself. And if anyone has the service manual for it... I would appreciate that too. Thanks
Matt Walker ), Lubbock TX Quote:
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