Mulja tv repair portal
Equipment Repairs => LCD TV forum => Topic started by: Turnip on October 31, 2019,10:33:15
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Hi folks,
Have had several in, where initially I replaced the duff 6v Leds, then had issues with the lenses. Just had one back where I replaced a Led in January 2019, to find another 6 Leds had gone S/C. Suspecting an issue, noted that a firmware update is suggested, which might, or might not, be useful.
Thought best to replace the three strips - Bit expensive at 30 Quid, but noticed when they arrived, they are now aluminium rather than original glass fibre which showed burn marks when removed.
Sadly, most folks just want a cheap job - Has an up-side on the sales side, as such sets can be re-sold with a new Led every year, then resold 'till they become unfashionable. Seems most folks don't care, as a hundred quid a year appears reasonable for folks who want instant gratification. We know them as 'Dorks' but who are we - Chris.
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I thought it was just me sticking a couple of lamps in and the others to go..... to be honest it's not worth the gamble especially on a 'paid job', OK for a temporary job to get someone by until they can afford a new set.
In this day and age you'd think there would be a system with trap door's or removable panels, that would be too easy wouldn't it?
I bet these mod con telly's just gets clobbered like the old valve telly's that was always left on til well after shut down.... been in many a house telly's been on and no ones watching.
Dave
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Hi Davy,
Guess after experience, you do the best for income and customers, Amazed as have had several crap UMC sets in for duff Leds, where I didn't expect them to last past guarantee due to Eeprom/M-Proc issues where the screen goes on and off repeatedly, where Eeproms don't suss the issue.
Surprisingly have replaced the odd Led, and the crap still works, as maybe only 3v Leds.
Tend to suspect LG 6v Leds a bit serious, especially using glass fibre strips.
Here's one for you, it's Panasonic and tubed - Admit hate it as needed charge my modern oscilloscope to find why the brightness control doesn't work, as seems it's done with pulses.
Hate pulses and oscilloscopes, as seems most stuff requires a panel change. Have to admit that back in the 60's, got a minor certificate in Black and White.
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Will be a pulse width modulator I guess.... I built one for someone using a 555 timer for controlling a 12V hefty lamp from a car battery, I had it driving a FET acting as a switch... worked like a charm from dim to full on, all I did was vary the off/on rate, not exactly pulse width though.
Built a uV light box some 315 LED's in three's, I has a 24V 5amp brick from something I clodded out yonks ago..... I needed appx. 10.7V or so at about 2.5A so I built a dc-dc converter using a LM2575-adj, careful with these because some are fixed voltages.... note: -ADJ. I can now set whatever brightness I want up to a limit. Quite surprised how much heat is generated, mind you I'm using SMD dropper resistors on each group.
Dave
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Hi Davy,
Admit a bit confused as dealing with a crap Panasonic tubed monitor.
Bit impressed though, how folks sort stuff - Chris.