Mulja tv repair portal
Equipment Repairs => DVD/VIDEO/Home Cinemas/Hi-Fi/Mp3/Camcorder => Topic started by: Turnip on June 28, 2018,13:07:06
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Hi folks,
Have this sound bar - OK apart from the Sub Woofer which doesn't function. Had a look where F931(2.5AT) was O/C.
Replaced but no secondary voltages. Might be STR Y6766B but unsure as it hasn't popped anything.
Found schematic so attach - Chris.
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Hi Chris, could well be the STR - they're known to lie doggo, especially when first powered on.
Some heat on the device often brings them back to life.
Bruce
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Thanks Bruce,
Was dubious as have lots of chips on the shelf, even coherers where the filings don't get it together.
Gave it a blast of heat, then a freeze - Nothing of course.
Think wait 'till the second one appears as seems the latest sets have a modicum of bass where sound bars maybe a thing of the past - Hope so, as even Sony sound bars appear to be rubbish - Chris.
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Thanks Bruce,
Replaced the STR and the PS was OK 'till I plugged it into the amp, where fuses popped. Had checked for shorts but found none. New STR is now duff as they don't like issues up them.
Thought to check the TAS5614LA audio chip noting no shorts - Seems incredible one might get 250 watts out of something the size of an SMD flattened Pea, even with 90% efficiency.
Gather chip cheap from China but currently unsure whether can sort all those pins, out and in - Chris.
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Hi Chris,
I've never had the courage to attempt replacing the SOP chips on home theatres and such, but surely there's protection in these things. I suspect you may have gotten a counterfeit IC. If you wander down that road again, substitute a 60/75W lamp for the fuse. Should prevent further pops. Guess you're too busy amusing Trump at the moment.
With the forum so quiet, I was beginning to think the UK had sunk below the waves.
Bruce
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Hi Bruce,
Fortunately Trump isn't calling, as Norfolk is just a blip on the East side of England - Mind you, we have some nifty golf courses though. Not tried any as the whole idea seems pointless - Rather buy STR chips and pop 'em, as at least it's fun, whether or not.
Invariably use a series lamp if dubious, but seems the STR went the same way as original, into a sort of 'sulk mode' popping nothing, but never to go again.
Not too keen to replace the chip, but chums have said I should get a pre-heater, so with a whiff of heat from the top, can lift it off.
Admit getting a chip off was never a problem as just flipped legs one at a time. Issue seems replacement where solder spreads about a bit. Tried 'Gull Wing' bits and solder-mop, but solder just seems to congregate where I can't reach it.
Thought try use solder paste, but it's messy and the chip slides out of sight along the panel - Fun though - Chris.
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hi turnip
did you cure this,just a note that subwoofer has to be powered on before main unit to be recognised its there otherwise main will mute it as being absent
regards
astracat
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Thanks 'Cat'
Seems the woofer SMD class D output chip if duff, as it's killed two STR P/S chips. The short blows two supply fuses but the STR doesn't recover, though it doesn't go S/C and pop the mains fuse.
Got the output chip on order, and when have the courage, I'll have a go replacing it - It's the size of a flattened pea with a lot of pins, and seemingly rated at 250 Watts - Nifty - Chris.