Insigna TV - GREEN????

[infiniteMPG]

We have an Insigna IS-TV040919 Color TV that has been working fine in
our son's room for years, A few weeks ago he complained about his TV
and when we checked, the color had a greenish-yellow tint to it. We
attempted to adjust the TV and no matter what we tried, the color
stays a greenish tint. We have been in touch with a few local service
places and they said it might be $75-$150 to fix this. Not being sure
what's wrong we're not sure if it's worth fixing or even knowing what
might be wrong.

Any clues as to what's wrong or if there's anything we might can do to
fix it (I'm a mechanical engineer and not afraid to pull electronics
apart).

All help would be greatly appreciated!

 

[William Sommerwerck]

This is likely due to a weakening of the red and blue guns.

Most sets have controls to set up the picture tube, to adjust for normal
sample-to-sample variation. Assuming your set has these controls, you can do
it yourself. But you have to know how to do it. Once you know what's
involved, it's trivial, but it takes too long to explain it here. Perhaps
someone can point you to a Website with instructions.

PS: Your son should not have a TV in his room. Toss the set.

 

[Bruce Esquibel]

With many CRT sets - IMHO most noticeable with Trinitron tubes - the red
gun ages more than the others due to being driven harder than the others.
Resulting in the tint you describe.

Hmm, maybe my memory is going with old age but...

1) The main point with the Trinitron tube was it only had one gun, thus
providing a better/different picture because there were fewer color
alignment problems. It used that special shadow mask and was the first crt
to use rectangle shaped color landings instead of the standard round hole
delta pattern everyone else used.

2) The blue gun (in non-trinitron tubes) was the one always pushed the
hardest because it's the color the human eye in most people was the least
sensitive to, so it needed the highest gain.

And I'm sure on #2, I remember the shorting alligator clips used on some of
the color generators that went into the grids of R/G connections on the
picture tube. You would kill off the red/green and bring up the blue just
below the point of blooming, then bring up the red/green to match and set
the gray scale.

Unless Sony came out with a 3 gun Trinitron towards the end (after I got out
of the tv repair biz), all Trinitrons only had a single gun.

-bruce
[email protected]


If anything, red was the minimum of the three.

 

[David]

Hmm, maybe my memory is going with old age but...

1) The main point with the Trinitron tube was it only had
one gun, thus
providing a better/different picture because there were
fewer color
alignment problems. It used that special shadow mask and
was the first crt
to use rectangle shaped color landings instead of the
standard round hole
delta pattern everyone else used.

(snip)

Sony advertises one gun in the Trinitron because PART of the
gun is in common with the three colors. It still has three
cathodes and heaters however. Just look at the neck of one
sometime. As far as the drive for the individual colors,
that is determined more by the phosphor efficiencies than
the human eye.

David