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Toshiba 40pw8db sound but no picture    
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Legion



Joined: 11 Apr 2009
Posts: 8
Location: Spain

PostPosted: Sat Apr 11, 2009 4:33 am    Post subject: Toshiba 40pw8db sound but no picture Reply with quote

I have been given a Toshiba 40pw8db projector TV. The red power light comes on, sound is heard from the speakers, relay clicks, the HOT circuit sounds like it fires up but the is no picture. The CRTs do not light up, altho there is a glow at the filaments.
All glass fuses are ok, nothing appears blown, I have resoldered capacitors and anything with a heat sink. Must be a component somewhere.
Any ideas?

Thanks
Google

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Legion



Joined: 11 Apr 2009
Posts: 8
Location: Spain

PostPosted: Mon Apr 13, 2009 9:21 am    Post subject: Reply with quote

For information, I managed to download a manual from Electromaniacs.com. Checking through the voltages, I found -10v on the E and B of Q404 - HOT (instead of -15v) and on Q301; Vertical output pin4 1.9v (should be 0.8v) and pins5,7 at 0 rather than 1.1 and 0.6 respectively. Could the Vout IC be defective?

Thanks
Legion



Joined: 11 Apr 2009
Posts: 8
Location: Spain

PostPosted: Tue Apr 14, 2009 10:45 am    Post subject: Reply with quote

More information: I adjusted the Focus/Screen controls and I got Red, Yellow and Blue narrow waves across the screen. Does this indicate no Vertical output or/and no video signal?

Thanks for any help
kuhurdler



Joined: 28 Dec 2006
Posts: 2879
Location: Overland Park, KS

PostPosted: Tue Apr 14, 2009 12:00 pm    Post subject: Reply with quote

that sounds like it to me.
Legion



Joined: 11 Apr 2009
Posts: 8
Location: Spain

PostPosted: Tue Apr 21, 2009 9:44 am    Post subject: Reply with quote

Update on the Projector:

I managed to get a Vertical output drive chip (LA7833, Q301) from a local repair shop, changed the chips over a hey presto I have a picture, sound everything.


:D
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kuhurdler



Joined: 28 Dec 2006
Posts: 2879
Location: Overland Park, KS

PostPosted: Tue Apr 21, 2009 11:57 am    Post subject: Reply with quote

Great. Thanks for posting back and letting us know.
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