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Toshiba CRT TV Fuzzy image

Bobi

May 2, 2016
2
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May 2, 2016
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So I recently bought an old CRT Toshiba TV to play retro games on it, and all was working well for about a week. Now when i turn it on, the image is fuzzy the tv makes high pitched noise and about 25s later the image gradually stabilizes and the noise also stops like it needs to heat up. Also day by day this problem only gets worse.

IMG_20160502_094656.jpg

^^^^TV image on start
--------------------------------------------

IMG_20160502_094658.jpg

^^^^TV image about 20sec after start
---------------------------------------------------

Also if the TV is working for an hour and then i turn it off, then turn it on again it works fine no fuzzy image or high pitched noises.

I have some beginner's experience in electronics. Please help me.
 

73's de Edd

Aug 21, 2015
3,636
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3,636
Sir Bobi . . . . .

Give us the brand and the model number of that Television.
Sound like you have some electrolytic capacitors that have just drifted down in capacitive value / effectiveness and increased their ESR to just barely working at an unstable threshold.
With the real info being in the statement "improves after warmup"
Get Mama Cass's blow drier at the ready and be prepared to also provide some close up photo s of the units . . .because . . .would you believe . . .we are currently as blind as bats here.


73's de Edd
 
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Heliman

Feb 4, 2016
65
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Feb 4, 2016
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65
Is the high pitch noise coming from the speaker or is it coming from inside the TV?
 

Bobi

May 2, 2016
2
Joined
May 2, 2016
Messages
2
Sir Bobi . . . . .

Give us the brand and the model number of that Television.
Sound like you have some electrolytic capacitors that have just drifted down in capacitive value / effectiveness and increased their ESR to just barely working at an unstable threshold.
With the real info being in the statement "improves after warmup"
Get Mama Cass's blow drier at the ready and be prepared to also provide some close up photo s of the units . . .because . . .would you believe . . .we are currently as blind as bats here.


73's de Edd
Thanx you were right, i took the multimeter, checked every single capacitor and found out that 4 of them all near the flyback transformer were with wrong capacitance and one of them was shorted out, so i replaced them with new ones and the TV works perfectly. This fix costed me less than 2$. Thanx again :) Woohoo
 

dorke

Jun 20, 2015
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Jun 20, 2015
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Thanx you were right, i took the multimeter, checked every single capacitor and found out that 4 of them all near the flyback transformer were with wrong capacitance and one of them was shorted out, so i replaced them with new ones and the TV works perfectly. This fix costed me less than 2$. Thanx again :) Woohoo
The high pitch noise is a classical fly-back problem.
Glad to hear you fixed it.
 
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