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Toshiba 40LB702B No sound

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Davy:
I suspect bad connections on the underside on the AF output chip.

Any repair tips on how to resolder?  This telly uses the Vestel 17MB65S-3 main board, all other functions are OK.

Dave

kennyc:
Hi Davy ,have never had any success fixing a board apart from taking a chance on replacing with one from Ebay . Usual fault is the sound goes of after a couple of hours and you turn it off and on and its OK again.  I usually tell customer to buy a cheap soundbar at Tesco for £25 and just charge them for a call out and advice if you can get away with it. Sometimes people will want you to go and buy one and install it

Davy:
Thanks kennyc, you are right.

I tried pressing darn hard on the chip  - no joy, I checked the four ceramic caps that give problems and they are OK. The supply voltage appears to be alright, so dunno guess it could be further back down stream.

Yep, me thinks a new board is required, or a 'goodun' at least,  gawd, bring back the ol' heavies, these modern things sound like pip and squeak - definitely not hi-fi.... lol, the sounds that clear you can hear the distortion.

Keep soldering, Dave

Turnip:
Hi Dave,

Had a few with either no sound or sound going off after a while. It was always those little ceramic caps - Never tested 'em just replaced with considerable difficulty as they tend to fly about a bit as it's hard to hold 'em down to solder.

Got a bag of 100 as I lose three for every one I fit, and can never find them again - Chris.

Davy:
There's four of em in a line, I guess they're the ones, I did test them for being s/c only, since the 12V line is OK I assumed they was OK.

I do have smds, do you know what they are off hand, 10n perhaps?  When I get time I'll pull em and try some in, I'll measure them on my LCR meter.

This one is stone dead on audio.... headphone socket included, there is a mod going about sticking a small heat sink on the NPT8030 chippy to help save the solder from heat damage.

These mod con tellies make there gramophones with a steel needle connected  to a soup can sound like hi-fi.

Dave

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