On Jul 8, 3:16*am, "N_Cook" wrote:
Don wrote in message

...





I have a 25 year old Sony KV-20XBR TV that's been darn near perfect
over a quarter of a century! *Amazing... last week, however, it
decided to die. *Here are the symptoms: 1). Color was obviously off,
so I checked it with a color-dot-bar generator. *It appears the Red is
gone, as the only bars seen are shades of blue and green, and 2).
Later, the picture slowly went to almost black -- you can make out
images, but vaguely.

Although I'm a tech (RF), I have no experience with TV
troubleshooting. *I know the TV is obsolete, but it's in "as new"
condition (not a scratch), and I really hate to take it to the
recyclers. *Any thoughts... do you think it might be in the red drive
circuit, focus circuit, the flyback, or the Trinitron CRT. *If it's
the latter, cost-effective repair is out the window. *I believe this
series of sets had a problem with cold solder joints. *Although I
doubt this is the problem, I thought I'd just mention it.

Thanks,
Don

I don't know what is wrong/right/different about my eyesight but I would
consider it torture being placed in front of a pixelated screen rather than
CRT for more than a couple of minutes. Every modern screen I've looked at
(briefly) - anything moving across the image , judders across , in an
intensely annoying manner . So I will will stay with CRT TV for as long as
possible.- Hide quoted text -

- Show quoted text -

There could be a number of causes of the problems mentioned. Lets
start with the "simple" potential fixes:

1) Check the driver transistors on the board that resides on the neck
of the CRT. Check for poor solder connections first. Check the
transistors with a checker for shorts as well. These should be marked
as R, G, B.

2) Check the solder connections at the flyback transformer. These
often crystalize.

3) There should be 2 controls on the flyback transformer itself. One
marked screen and one focus. Try working the screen one back and
forth a bit. I have seen poor contacts inside these cause a dimming
of the picture as well.

Perform the above and report back with the results. I will lok up the
service manual for this model and post any additional common failures
later today.

Dan