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-   -   TV color turning red (http://www.videokarma.org/showthread.php?t=258419)

qguy 06-09-2013 06:36 AM

TV color turning red
 
I have this Sony CRT tv, suddenly the color has a red hue, color adjustment does not help. Is this something that can easily/cheaply fixed ? The effect is that screen seems to be covered by red celophane

I have soldering and contact cleaner experience with vintage audio receivers :D

zeno 06-09-2013 08:45 AM

What is the model number KV????

73 Zeno:smoke:

qguy 06-09-2013 06:07 PM

The model is KV25XBR

Thanks

zeno 06-09-2013 06:49 PM

OK I dont have a manual so a couple of things to check.
First turn the color level all the way down.
If it looks B&W then you have a color problem that will be deep.
If it is red you have a chance.
IMPORTANT if you pull the back take the speakers off 1st.
A newer XBR set had an exploding back, taking it off would cause
it to shatter. Be gentile with it.

Look at the CRT socket board. There are usually 3 controls
R, G, &B. Try turning the R down.
Also look for bad connections especially where there are 3
identical transistors. It can be a shorted CRT. LIGHTLY tapping
the tube neck will sometimes make it flash back to normal.
but so will a bad connection on the board.
Last thing you can try is swapping the 3 identical transistors.
If it turns a different color one of them is bad, you can take
it from there................
Beyond that it gets deep.
Good luck

73 Zeno:smoke:

qguy 06-09-2013 09:54 PM

Thanks

cleaned the tube socket and soldered some cold solders on the tube socket. The red is now gone, but the TV needs some more brightness, I had to adjust the picture and brightness setting to full get acceptable brightness. The brightness trimmer on board is on full. Are there any other trimmers I can adjust to boost the brightness ?

Thanks again

zeno 06-10-2013 06:34 AM

Quote:

Originally Posted by qguy (Post 3071884)
Thanks

cleaned the tube socket and soldered some cold solders on the tube socket. The red is now gone, but the TV needs some more brightness, I had to adjust the picture and brightness setting to full get acceptable brightness. The brightness trimmer on board is on full. Are there any other trimmers I can adjust to boost the brightness ?

Thanks again

Progress :banana:
Find the G-2 control. It may be the one you turned. I think it
was on the CRT skt on that set but may be on or near the HV transformer.
Its usually a fairly beefy control compaired to the others.
You will need a meter. Check the resistors going to it. They do
open. Basic set up is: one end of pot goes to apx 200 DVC
the other end goes to apx 800 VDC through a resistor.
Wiper goes to CRT G-2 pin & has 400-500 VDC on it.
Dont confuse with the H-STAT control !
When done turn up G-2 slowly til thin white lines
appear then back it off. Darken room & turn brightness down.
be sure there are no lines in pix and it either is black or very dim.
Good luck

73 Zeno:smoke:

qguy 06-10-2013 09:45 AM

Thanks all the trimmers on the CRT socket board were all the same kind. I already closed the TV for now, I will look for that G-2 control trimmer

Thanks !!!


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