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old Toshiba cf3264k TV, retrace lines in picture
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shawncao



Joined: 20 Jun 2007
Posts: 6

PostPosted: Wed Jun 20, 2007 5:36 am    Post subject: old Toshiba cf3264k TV, retrace lines in picture Reply with quote

An old Toshiba cf3264k TV - The screen was too bright and had retrace lines in it.
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minnie



Joined: 18 Aug 2005
Posts: 2877
Location: Hell

PostPosted: Wed Jun 20, 2007 10:56 pm    Post subject: Reply with quote

Try turning down the screen control on the flyback, if it's still there, bad CRT.
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bbp1



Joined: 04 May 2007
Posts: 22

PostPosted: Thu Jun 21, 2007 8:14 am    Post subject: Reply with quote

there can be other faulty comp causing symptom- before condemning tube, I would check electros, res, djs etc. If tube is suspect, there are ways to rejuvenate/ fix problem- but must know what doing- I know from hard won experience & making equipment needed how to do- but really, do you think anyone asking such a basic thing could do it?!- I think not!!. Confused
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shawncao



Joined: 20 Jun 2007
Posts: 6

PostPosted: Sun Jun 24, 2007 5:38 pm    Post subject: re Reply with quote

Thanks, both of you. Let me describe the problem a little more in details.
The screen is bright, the picture is pale but stable, and the white retrace lines are full of the screen. I had tried to turn down the screen control voltage, the retrace lines were gone, but the screen and the picture became very dark. I have already replaced a cap on CRT control board which is attaced to the end of the CRT.
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cory
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PostPosted: Mon Jun 25, 2007 12:46 am    Post subject: Reply with quote

check 200 volt line going to crt neck pcb. if low find capacitor, probably near flyback.
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mazmaz



Joined: 23 Jan 2005
Posts: 50

PostPosted: Mon Jun 25, 2007 5:59 am    Post subject: Reply with quote

hello
low voltage in cathods driver (180~200) may cause this problume(check fbt out line to dc circuit diode cap , ....)
if problume not stay in stable mode (variable screen voltage) change fbt
bad video driver circuit too may made this problume(zener diods,driver ic ...)
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shawncao



Joined: 20 Jun 2007
Posts: 6

PostPosted: Tue Jun 26, 2007 5:50 am    Post subject: Reply with quote

The voltage is around 60-70 V. Trying to figure out the defect component now...
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cory
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PostPosted: Tue Jun 26, 2007 12:16 pm    Post subject: Reply with quote

there should be a capacitor near flyback rated at least 250 volts.follow connector back from crt onto main pcb.there will be a diode and cap right off flyback secondary.change cap.
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shawncao



Joined: 20 Jun 2007
Posts: 6

PostPosted: Wed Jun 27, 2007 6:00 am    Post subject: Reply with quote

Thanks cory. I found 2 caps (33uF 200V); and 1 cap (33uf 250v) which connects with a diode. But none of them seems defect. (I used a multi-meter to check them on board).
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shawncao



Joined: 20 Jun 2007
Posts: 6

PostPosted: Wed Jun 27, 2007 6:02 am    Post subject: Reply with quote

BTW the P/N of the pcb where flyback located is PW9533-1.
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