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Toshiba 32BV701B audio fault

bikemech

Oct 23, 2014
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just been given a 32 inch toshibe tv, the previous owner said the set works fine, but after a short while the sound goes off!
then if you turn it off and let it cool it comes back for a while then goes off again,

i have powered the tv up and it does indeed come on, there is a strange zub zub zub noise from what i believe is a transformer on the main PSU, i havent actually tryed watching it yet to find out how long it lasts,
the PSU is a VESTEL 17pw25-4

anyone seen this before?
 

bikemech

Oct 23, 2014
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oh,
also all the caps look to be in good shape as far as i can tell
 

KrisBlueNZ

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Are you sure the model number is 32BV71V? I get no hits for that model number except for this thread here!
 

KrisBlueNZ

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Well, I found a service manual for the 32BV700B on Elektrotanya at http://elektrotanya.com/toshiba_32bv700b_chassis_17mb45m-3.pdf/download.html. I expect this will be pretty similar to the 701B. But that manual doesn't have a full schematic, and it doesn't show the audio circuitry.

Can you take a photo of the board in the area where the speakers connect?

Does the sound continue to work properly through the line outputs while the speakers are dead?
 

shrtrnd

Jan 15, 2010
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My experience with this type of problem is that one of your semiconductors interrupts the circuit when it gets hot.
The quick and easy way to isolate the problem is to buy a can of 'freeze spray', and individually hit each suspect semiconductor.
Your sound will come back when you've got the right semiconductor, and you will know which one needs to be replaced.
 

bikemech

Oct 23, 2014
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7CE7BCA0-DEB5-4319-AA37-923B4312D452_zpsatdtnrkm.jpg
B84E1BAD-158F-4B4B-8A53-1F024AF3746B_zpso7steu56.jpg
E4852F37-04D5-4B7F-BCD7-CAF2489BBD5A_zpsoajy6w1x.jpg
Sorry again for picture quality.
 

KrisBlueNZ

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Can you take a photo of the board in the area where the speakers connect?

Does the sound continue to work properly through the line outputs while the speakers are dead?
 

bikemech

Oct 23, 2014
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Sorry kris haven't had time to check this yet, will do it ASAP
 

bikemech

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the first photo in post #7 kris is where the speakers connect to the main board
 

KrisBlueNZ

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OK, what are the markings on the IC just below the SCART connector? It looks like the circuit reference is U158.
Does the sound continue to work properly through the line outputs while the speakers are dead?
 
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