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Equipment Repairs => CRT TV forum => Topic started by: Turnip on October 04, 2010,11:57:20

Title: Toshiba 32YT56B2 - Vestel AK49-7
Post by: Turnip on October 04, 2010,11:57:20

Hi folks,

Have one of these where on switching on and bringing out of standby, set clicks a few times (degauss), sometimes a normalish raster appears, sometimes not, then set cuts to s/by and can only be brought on again by on/off switch.

Had that 'Vestel Eeprom' feeling but AK49 isn't known for that problem, more M/proc failure - geometry seems normal and HT is 150'ish -  secondary diodes are OK and nothing smokes.

Any thoughts ?  - Chris.

Title: Re: Toshiba 32YT56B2 - Vestel AK49-7
Post by: brainstorm on October 05, 2010,06:35:44

Hi Chris,

The Line driver transistor are unreliable in these sets (Q601 - BS170)

I had one of these a few months back doing similar things, I replaced Q601 and resoldered around the line driver transformer and so far it hasnt bounced back !!

I have written in my little book that I had a intermittent fault with C826 1n/2kv being faulty, but i recall that when i examined it that it had a burn mark in the body of the capacitor

The only other thing I have had is the big flat pack micro that is mounted on the print side of the board being intermittent, but im afraid if that is faulty then its "Good night Vienna"

Brian

Title: Re: Toshiba 32YT56B2 - Vestel AK49-7
Post by: daz on October 05, 2010,07:38:57

hi chris
have the following faults listed:-
burst of eht then shuts down - lopt + tda6108jf
in sby - c604,470uf,16v + 47uf 250v (havnt writen circuit ref??)
and as brian said q601 and line drive coil dry
good luck
daz

Title: Re: Toshiba 32YT56B2 - Vestel AK49-7
Post by: Turnip on October 05, 2010,12:20:21

Hi and thanks Brian and Daz,

Didn't find this sort'a info on Highland or Quuq AK49 sites, will give thoughts a go, and report.

Many thanks, must admit I hate those hernia inducing flat screen tube sets these days - give me a Profilo with weeping caps anytime. Gather someone rewinds that little S/by tranny for much cash  -impressed. 

Have latest NHS Hernia jobby awaited, where they go in at the wallet and it's said to be pain free - tell Sparky.

Only Vestel/Profilo lightweights 'till then - Chris.

Title: Re: Toshiba 32YT56B2 - Vestel AK49-7
Post by: Turnip on October 07, 2010,13:12:37

Hi and thanks again,

Back to the set checking line drive FET, transformer dries and such. Found that on switch on, set continually tried to start, and a familiar smell came from LOPT.

Surprised as have rarely had a duff LOPT recently without the LOPTR going S/C.

Thanks for help, off to Wiltsgrove for a cheapy, hopefully - Chris.

Title: Re: Toshiba 32YT56B2 - Vestel AK49-7
Post by: brainstorm on October 08, 2010,04:25:11

Hi Chris

I have had LOPTX failure, but never had a intermittent one

But there is a first time for everything

Brian

Title: Re: Toshiba 32YT56B2 - Vestel AK49-7
Post by: Turnip on October 08, 2010,12:33:03

Hi Bri, and well said,

Was doubtful meself, but off to Wilts and Chas/Hyde to discover LOPTs are currently either unavailable or stocked at incredible cost with new tube base (Guess which)

Confess -  Bri - I have never before had one that showed an occasional picture - Honest - Chris.

PS Confess that inititially there was some decent pic (Honest) but after all that helpful advice and switch on's the trannie started to smell - awful glad, really.