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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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Widescreen Blue Blooming TV ! 1yr later goes flashes Green and shuts down ...nice
Hi
TV has started flashing green and shutting down. Did this once a month or so now every few hours. Sometimes, TV steadies after green flash and recovers only to shut down later. Suggestions for a fix include: 1. Intermittent H-K carbon particle short - 1kV - 2amp diode on CRT board may fix gun short 2. Common particle green cathode to heater short ? Any ideas or advice appreciated Thanks JM PS Details of previous problem with same set a year inlcudes that ended in a CRT replacement. JVC AV-32WP2EK 32" All 6 messages in topic - view as tree From: JM - view profile Date: Thurs, Feb 17 2005 2:44 pm Email: "JM" Groups: sci.electronics.repair Not yet ratedRating: show options Reply to Author | Forward | Print | Individual Message | Show original | Remove | Report Abuse | Find messages by this author Hi I have the above model 32" widescreen TV that intially starts up OK for first 30secs but then blooms into blue with thin horozontal sloped lines in blue. Blueness gradually fades over the next 10-20minutes to a perfect picture which lasts without further problem. Checking the web a positor preventing degaussing appears a possibility. Though switching on/off doesn't help much and no speakers are near by and TV has been unplugged and started repeatly. Any other suggestions / theories ? Can using service mode help further ? Thanks JM From: b - view profile Date: Fri, Feb 18 2005 1:10 am Email: (b) Groups: sci.electronics.repair Not yet ratedRating: show options Reply to Author | Forward | Print | Individual Message | Show original | Report Abuse | Find messages by this author - Hide quoted text - - Show quoted text - "JM" wrote in message ... Hi I have the above model 32" widescreen TV that intially starts up OK for first 30secs but then blooms into blue with thin horozontal sloped lines in blue. Blueness gradually fades over the next 10-20minutes to a perfect picture which lasts without further problem. Checking the web a positor preventing degaussing appears a possibility. Though switching on/off doesn't help much and no speakers are near by and TV has been unplugged and started repeatly. Any other suggestions / theories ? Can using service mode help further ? Thanks JM Are you talking about retrace lines? this is almost certainly not a degauss problem. dont touch the service mode, this sounds like component failure. check: components on crt neck board, video drivers, possibly crt socket? - B Rate this post: Text for clearing space From: Phil Bowser - view profile Date: Fri, Feb 18 2005 5:35 am Email: "Phil Bowser" Groups: sci.electronics.repair Not yet ratedRating: show options Reply to Author | Forward | Print | Individual Message | Show original | Report Abuse | Find messages by this author I agree with "b" - it certainly does not sound degaussing related, based on your description of the problem. The only thing that "puzzles" me about the situation is your description of "gradually" returning to normal. In the event of either solder connections, or a H-K short I would expect the screen to abruptly change from normal to blue (or green) (or red), but not gradually... If it were in front of me, I would be using the old beat-on-it routine to try and decide if you're dealing with solder connections or a tube. If minor bumps to the cabinet or movement of the set corrects it, it is probably solder connections. If it requires a really hard slap to the face of the tube with the palm of your hand, I would say you've got an intermittent H-K short in the CRT (Picture tube). If it doesn't respond at all to this tormenting, you're probably looking at some solid state failure / electrically leaky component like a video drive transistor, or AKB feedback component (You'll need a schematic & parts list.) Due to the fact that the symptom CHANGES, - leave the service menus ALONE! - You'll only create for yourself another problem you'll have to go back and correct once you fix the real problem. "JM" wrote in message ... - Hide quoted text - - Show quoted text - Hi I have the above model 32" widescreen TV that intially starts up OK for first 30secs but then blooms into blue with thin horozontal sloped lines in blue. Blueness gradually fades over the next 10-20minutes to a perfect picture which lasts without further problem. Checking the web a positor preventing degaussing appears a possibility. Though switching on/off doesn't help much and no speakers are near by and TV has been unplugged and started repeatly. Any other suggestions / theories ? Can using service mode help further ? Thanks JM Rate this post: Text for clearing space From: JM - view profile Date: Fri, Feb 18 2005 11:32 am Email: "JM" Groups: sci.electronics.repair Not yet ratedRating: show options Reply to Author | Forward | Print | Individual Message | Show original | Remove | Report Abuse | Find messages by this author Phil Phil I like your style...slap the TV about a bit, make it talk Jack Bauer style. Few more details: Picture always starts good 30sec-1mins ish. Blueness appears and intensifies until picture is bleached out completely but then gradually the picture reappears and the blueness fades. Sometimes the blueness fades quickly 5mins, picture can then flicks from perfect to over colored (usually yellowy) I mean deeper tonal/contrast for a split second then flicks back less than a second to normal. TV has then run for 5mins but then apparently shorts out and shuts down - but its only done this 2/3 times. Usually, the picture stabilises and set will run fine for hrs on end. However, restarting the TV when warm doesn't prevent problem, just starts over again, stabilises and then OK. A TV tech friend is coming round Sat, he thought "CRT short" but expected set to short out everytime after a few minutes. I'll give it a good seeing to tonight :-).and see what happens. Thanks JM "Phil Bowser" wrote in message ... - Hide quoted text - - Show quoted text - I agree with "b" - it certainly does not sound degaussing related, based on your description of the problem. The only thing that "puzzles" me about the situation is your description of "gradually" returning to normal. In the event of either solder connections, or a H-K short I would expect the screen to abruptly change from normal to blue (or green) (or red), but not gradually... If it were in front of me, I would be using the old beat-on-it routine to try and decide if you're dealing with solder connections or a tube. If minor bumps to the cabinet or movement of the set corrects it, it is probably solder connections. If it requires a really hard slap to the face of the tube with the palm of your hand, I would say you've got an intermittent H-K short in the CRT (Picture tube). If it doesn't respond at all to this tormenting, you're probably looking at some solid state failure / electrically leaky component like a video drive transistor, or AKB feedback component (You'll need a schematic & parts list.) Due to the fact that the symptom CHANGES, - leave the service menus ALONE! - You'll only create for yourself another problem you'll have to go back and correct once you fix the real problem. "JM" wrote in message ... Hi I have the above model 32" widescreen TV that intially starts up OK for first 30secs but then blooms into blue with thin horozontal sloped lines in blue. Blueness gradually fades over the next 10-20minutes to a perfect picture which lasts without further problem. Checking the web a positor preventing degaussing appears a possibility. Though switching on/off doesn't help much and no speakers are near by and TV has been unplugged and started repeatly. Any other suggestions / theories ? Can using service mode help further ? Thanks JM From: JVC Dude - view profile Date: Fri, Feb 18 2005 8:10 pm Email: "JVC Dude" Groups: sci.electronics.repair Not yet ratedRating: show options Reply to Author | Forward | Print | Individual Message | Show original | Report Abuse | Find messages by this author Certainly sounds like the tube to me... The Philips 32" tubes used in these sets have been much more reliable than the 28" wide and 29" 4:3 ones from the late 90s, but the change of colour cast is a similar tell tale sign... gentle!! tapping on the tube neck might cause flashes or casts to change, confirming the diagnosis. Sometimes you can clean them up with a tube rejuvenator but these tubes have a very low heater tolerance to the increased voltage used in the boost/clean process- The heater for one colour can easily fail !! AW "JM" wrote in message ... - Hide quoted text - - Show quoted text - Phil Phil I like your style...slap the TV about a bit, make it talk Jack Bauer style. Few more details: Picture always starts good 30sec-1mins ish. Blueness appears and intensifies until picture is bleached out completely but then gradually the picture reappears and the blueness fades. Sometimes the blueness fades quickly 5mins, picture can then flicks from perfect to over colored (usually yellowy) I mean deeper tonal/contrast for a split second then flicks back less than a second to normal. TV has then run for 5mins but then apparently shorts out and shuts down - but its only done this 2/3 times. Usually, the picture stabilises and set will run fine for hrs on end. However, restarting the TV when warm doesn't prevent problem, just starts over again, stabilises and then OK. A TV tech friend is coming round Sat, he thought "CRT short" but expected set to short out everytime after a few minutes. I'll give it a good seeing to tonight :-).and see what happens. Thanks JM "Phil Bowser" wrote in message ... I agree with "b" - it certainly does not sound degaussing related, based on your description of the problem. The only thing that "puzzles" me about the situation is your description of "gradually" returning to normal. In the event of either solder connections, or a H-K short I would expect the screen to abruptly change from normal to blue (or green) (or red), but not gradually... If it were in front of me, I would be using the old beat-on-it routine to try and decide if you're dealing with solder connections or a tube. If minor bumps to the cabinet or movement of the set corrects it, it is probably solder connections. If it requires a really hard slap to the face of the tube with the palm of your hand, I would say you've got an intermittent H-K short in the CRT (Picture tube). If it doesn't respond at all to this tormenting, you're probably looking at some solid state failure / electrically leaky component like a video drive transistor, or AKB feedback component (You'll need a schematic & parts list.) Due to the fact that the symptom CHANGES, - leave the service menus ALONE! - You'll only create for yourself another problem you'll have to go back and correct once you fix the real problem. "JM" wrote in message ... Hi I have the above model 32" widescreen TV that intially starts up OK for first 30secs but then blooms into blue with thin horozontal sloped lines in blue. Blueness gradually fades over the next 10-20minutes to a perfect picture which lasts without further problem. Checking the web a positor preventing degaussing appears a possibility. Though switching on/off doesn't help much and no speakers are near by and TV has been unplugged and started repeatly. Any other suggestions / theories ? Can using service mode help further ? Thanks JM Rate this post: Text for clearing space From: John Mercer - view profile Date: Sun, Feb 20 2005 4:42 pm Email: "John Mercer" Groups: sci.electronics.repair Not yet ratedRating: show options Reply to Author | Forward | Print | Individual Message | Show original | Report Abuse | Find messages by this author Confirmed as tube......replacement with a 2yr one is going to be £100inc P&L so probably try that! Thanks JM |
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