CONVERGENCE ADJ. FOR PROJECTION TV...Where to start !

B

Bentech

Guest
Hi , I have a projection TV RCA Model P46732 (CTC169) with a major
convergence problem...

Somebody had played with convergence pots (~75 pots) , and now the pic is
worse than before.

I want to adjust at his maximum , I have a good test pattern generator but
I don't know where to start to adjust the convergence.

I assume that the adjustment of a projection TV is standard so I need help
on this one...

If a service manual is needed , I will buy it but I don't really think w
need it for these adj.

There is also a small test pattern (+) to ajust the 3 colors...
Thanks..
 
Thanks for your prompt response. Where can I get the procedure for this
chassis ? I know that RCA are selling these but very expensive...


"David" <dkuhajda@locl.net.spam> a écrit dans le message de news:
3fca624d@news.greennet.net...
Your assumption is incorrect about all RPTV sets convergence adjustment
being standard. Each manufacture has its own specific procedure to
follow.
The only thing that is standard is the geometry of the green is squared up
first with the red and blue covered up, then the red then the blue in that
order gets lined up with the green. Most convergence setups require that
you start at the center and work your way out to the edges.

The service manual probably will not give enough information for that set
but the training manual that includes the convergence adjustment procedure
should.

If it is way out, I would start by putting all adjustments in the center
of
the adjustment range (or wherever the procedure states to start out)
and/or
trying to visually look at the controls to see if it is possible to
determine where they were before moving them. You will have to know
exactly
whar each control does so the adjustment procedure will be a must.

There is also a very good possibility that the person who screwed with
the
adjustments wound up hiding a failure in the convergence circuit, which
will
make the job even tougher, except for someone with LOTS of experience on
the
PTK169 series chassis and convergence procedure (they would know if the
controls are not working correctly).

David

Bentech <maxmel11@yahoo.ca> wrote in message
news:jhpyb.2334$zf2.96314@news20.bellglobal.com...
Hi , I have a projection TV RCA Model P46732 (CTC169) with a major
convergence problem...

Somebody had played with convergence pots (~75 pots) , and now the pic
is
worse than before.

I want to adjust at his maximum , I have a good test pattern generator
but
I don't know where to start to adjust the convergence.

I assume that the adjustment of a projection TV is standard so I need
help
on this one...

If a service manual is needed , I will buy it but I don't really think w
need it for these adj.

There is also a small test pattern (+) to ajust the 3 colors...
Thanks..
Click to expand...
 
Your assumption is incorrect about all RPTV sets convergence adjustment
being standard. Each manufacture has its own specific procedure to follow.
The only thing that is standard is the geometry of the green is squared up
first with the red and blue covered up, then the red then the blue in that
order gets lined up with the green. Most convergence setups require that
you start at the center and work your way out to the edges.

The service manual probably will not give enough information for that set
but the training manual that includes the convergence adjustment procedure
should.

If it is way out, I would start by putting all adjustments in the center of
the adjustment range (or wherever the procedure states to start out) and/or
trying to visually look at the controls to see if it is possible to
determine where they were before moving them. You will have to know exactly
whar each control does so the adjustment procedure will be a must.

There is also a very good possibility that the person who screwed with the
adjustments wound up hiding a failure in the convergence circuit, which will
make the job even tougher, except for someone with LOTS of experience on the
PTK169 series chassis and convergence procedure (they would know if the
controls are not working correctly).

David

Bentech <maxmel11@yahoo.ca> wrote in message
news:jhpyb.2334$zf2.96314@news20.bellglobal.com...
Hi , I have a projection TV RCA Model P46732 (CTC169) with a major
convergence problem...

Somebody had played with convergence pots (~75 pots) , and now the pic is
worse than before.

I want to adjust at his maximum , I have a good test pattern generator
but
I don't know where to start to adjust the convergence.

I assume that the adjustment of a projection TV is standard so I need help
on this one...

If a service manual is needed , I will buy it but I don't really think w
need it for these adj.

There is also a small test pattern (+) to ajust the 3 colors...
Thanks..
Click to expand...
 
On Sun, 30 Nov 2003 11:54:58 -0400, "Bentech" <maxmel11@yahoo.ca>
wrote:

Hi , I have a projection TV RCA Model P46732 (CTC169) with a major
convergence problem...

Somebody had played with convergence pots (~75 pots) , and now the pic is
worse than before.
Click to expand...
Convergencing is no big issue, those pots are grouped in columns for R
and B and for each quarters in another group. Yours should have a
sticker for this convergence adjustment board.

Begin checking that all CRT is centered with strings across the screen
meeting at center using the "+" then straighten out convergence. The
rough centering is done with rings on CRTs.

This is my favorite part because this is very hand-on than via
software and quicker.

Most I see convergence both R and B onto G because G is the center of
all guns and is least distorted.

Cheers,

Wizard
 
OK, the first thing to do is cover the red and blue lenses and set all the
controls to midrange. You must get the green geometry correct first. Size,
linearity, skew, bow, tilt, pin and key or trap. IIRC this one doesn't use sub
pin and sub skew, but if the controls exist they are used to correct when you
have to compromise. Once you get the green right, move on to the blue. leaving
the red lens covered. Always start with size and lin, and adjust them to
converge vertical lines at the sides along the horizontal centerline and then
horizontal lines at top and bottom along the vertical centerline.

After the the pin, trap or key and a few specialized side edge controls are
used in that set. BTW, if the H lin pots have no effect the problem is likely
the DF transformer. Suspect this especially if you can't obtain good electrical
focus in the corners and center simultaneously.

These sets have a pretty good control set and you should be able to get it with
a raster line throughout the screen. The only better control set I've sen is on
the EXR/XBR Sony series that still used pots. The only thing better is the
cursor based digital systems, of which this is not. The pioneer is also good in
that respect.

If you're in Ohio and really FUBAR it up, I might be able to come do it. As
another respondant wrote, there probably is a convergence problem that someone
tried to cover up. You will find this out by either certain controls not
working properly or or not at all. I'm sure you can probably tell if some are
not working at all, but it takes experience to know when they are not working
properly.

Good luck.

JURB
 
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