K4900 brightness

mike11

Active member
Joined
Mar 7, 2012
Messages
1,617
Reaction score
9
Location
Pennsylvania
What bedsides caps would cause uneven brightness ?? Chasis had full recap and tube rejuvenate ... this is what I have
 

Attachments

  • image.jpg
    image.jpg
    509.6 KB · Views: 41
Flyback. I assume you've done the proper adjustments? Turn the brightness all the way down, turn the flyback screen pot up until you get the raster lines, then turn it down until the raster lines barely disappear, then turn the brightness up to desired level. If that doesn't get you going, then I'd suggest replacing the flyback. Looks like your colors aren't quite right either.
 
Last edited:
I don't get raster lines with the screen pot turned up just an uneven flood of white .... flat was also changed and have this now
 

Attachments

  • IMG_9567.jpg
    IMG_9567.jpg
    511.9 KB · Views: 16
Check solder joints and trace continuity at electrolytic capacitors C506 (22 uf @ 160v) and C507 (47 uf @ 160v).

Those all check ought and zero out ok
Still doing the same ...
as of now all electros were changed
Fly changed
Neck board swapped ...
This is driving me nuts
 
Check for 175 volts on pin 1 of P402 on the neck board. It also looks like you might be missing your green color.

Do you have a TPG? If so use it to test to see if your green color circuit is working. Or switch Q402 and Q403 and see if green comes back and the blue disappears.

Ed
 
Back
Top Bottom