Joe Paulson wrote in a message to All:

 JP>  My old 27"Zenith TV finally gave up.I smelled burnt insulation.
 JP> Reading the TV ads put me in a quandry.The technology is in
 JP> transition.So I went down to the Goodwill auction and bought a used
 JP> 27" RCA TV for $10.
 JP>  
 JP>   Usually these electronics have some defects that I often can work
 JP> around.Opening it up,I found very little dust.Everything looked
 JP> good except the color.All white images had a yellow tint no matter
 JP> how I adjusted the COLOR,TINT,CONTRAST,GREEN-RED mix.I tried the
 JP> default setup.All no help.Using the default setup,the faces of
 JP> people had a  bluish tint.In the back,I could see some screwdriver
 JP> color adjustments but these had no effect.

Which adjustments are you talking about there?

 JP> I could see controls for SCREEN and FOCUS but I didn't have the 
 JP> required small diameter tool with a hex head. So I carefully 
 JP> drilled a lot of 1/8",then 1/4" holes around the hole marked 
 JP> SCREEN and cut out the plastic.Then I used a  9/64 " hex bit to 
 JP> rock the high wattage pot and saw no change.

No change at all?  That's odd.  I hope you put it back where it was.

 JP> The board on the socket of the TV tube didn't have the red,green
 JP> and blue pots that I was familiar with.

They may not be there as accessible from the back of the set,  they may be
able to be gotten from the side of that little board.  But this is probably
what you need to adjust.

 JP>   Now,I beginning to think that the magnet adjustments on the neck
 JP> of the TV tube may need tweaking.

You probably *don't* want to go there!

 JP> There are 3 sets and I was waondering which one I should start 
 JP> with.I would watch to make white images less yellow.  Any 
 JP> suggestions?

Yeah.  Leave those magnets alone!  There will be two sets of them,  one for
color purity and one for static convergence.

Have you had the back off the set yet?  If not,  that's your next step, 
and have a good close look at that board on the back of the tube.  If the
adjustments really aren't there then they'll be on the main board
somewhere.  There should be at least three of them,  sometimes as many as
six.

The next thing you need to do before you start messing with these is to
turn the color all the way down,  so you get a black-and-white picture.  If
that does give you a black-and-white picture,  and there are no tints in
there, then your problems lie elsewhere.  Make sure that you not only turn
the color level (sometimes labeled chroma) control all the way down,  but
that you disengage any "auto color" or similar buttons,  which
typically set a minimum for this stuff that you can't go below.

If you're looking at those adjustments,  and the bits you move are metal,
then you *WILL* need a non-metallic adjustment tool.  Those metal bits are
at voltage,  and shorting them out to something else will create a problem
for you that you don't have now.

By no means start tweaking stuff here and there,  some things in there you
throw out of adjustment and you'll need specialized test equipment to get
it adjusted properly again.

Once you have a black-and-white picture,  then you can adjust the drive
controls for a good color in the brighter portions of the picture.  There
may be separate screen controls for each color,  these,  or the main screen
control on the flyback,  affect the background darker parts.  They interact
to some degree.

If you need to adjust focus,  do that _first_.  And if you find that you
need to touch it up for some reason,  then you may need to tweak the other
adjustments again.

Post what you find in there and I'll go on about this a bit more.


---