Red/Green/Blue mis-alignment on Phillips/Magnavox 25In TV

[jim w]

The colors seem to have come out of alignment on my tv. For example, if
I have closed-captioning running, I can see a "ghose" of red above and
blue below that white lettering.

Possibly related, for a few weeks before the the "focus" went away, the
tv was "humming" (sounded like 60HZ noise to me).

I'd just as soon try to fix this myself if someone can give me some
pointers. I'm handy with digital stuff, but haven't done any TV repair
before.

Thanks
- jim

 

[[email protected]]

You need to apply the proper signal generator and do a full yoke
purity, convergence, and geometry adjustment.

 

[jim w]

Ok.. thanks... but... a followup question.. why would the focus have
gone bad to begin with?

 

[Ol' Duffer]

The colors seem to have come out of alignment on my tv. For example, if
I have closed-captioning running, I can see a "ghose" of red above and
blue below that white lettering.

The term for this is convergence. Or in your case, misconvergence.

Possibly related, for a few weeks before the the "focus" went away, the
tv was "humming" (sounded like 60HZ noise to me).

This may have been the yoke rattling at the vertical scan rate.
The yoke is a molded and glued mess of ferrite, sheet metal, and
plastic wound with specially shaped coils of wire that fits over
the neck of the CRT, and has the job of deflecting the electron
beams to generate the sweep (raster).

Part of the factory convergence procedure involves warping the
yoke to move the center of its magnetic fields into the best
position for the colors to line up. They jam rubber wedges
or strips of cardboard under it to hold its shape. With age,
the plastic can sag or crack, glue gets brittle, and sometimes
things get loose internally.

There is a good chance you would have to replace the yoke to
get it right, and they are pricey. The alignment procedure is
best done with a pattern generator, and can be tricky.

I'd just as soon try to fix this myself if someone can give me some
pointers. I'm handy with digital stuff, but haven't done any TV repair
before.

If you are lucky, one of the rubber wedges may have fallen out
from dried-up glue, and you can jam it back in place and improve
convergence. The fates are not usually so kind. You can also
fiddle with the rings on the CRT neck, and maybe improve it a
bit. Make note of their original position so you can start over
if you make things worse. This is about all the average do-it-
yourselfer can do.

 

[RonKZ650]

The yoke is bad like Ol Duffer said. Pretty common failure.

 

[ChrisCoaster]

Part of the factory convergence procedure involves warping the
yoke to move the center of its magnetic fields into the best
position for the colors to line up. They jam rubber wedges
or strips of cardboard under it to hold its shape. With age,
the plastic can sag or crack, glue gets brittle, and sometimes
things get loose internally.

THIS is how they build TELEVISIONS!?! Yikes!!! No wonder they go out
of tune so fast and so unpredictably. No wonder I have to re-focus a
brand new Sony that just came in the house! "Jam rubber wedges"??? I
thought that's how they loosened up or tightened up the handling of
NASCAR race cars!!!

"Get loose internally...with age"? It'll get loose just moving it
across the room to where it will be watched! LOL

Thanks for bringing this up - that's scary!

-CC

 

[Ol' Duffer]

THIS is how they build TELEVISIONS!?! Yikes!!! No wonder they go out
of tune so fast and so unpredictably. No wonder I have to re-focus a
brand new Sony that just came in the house!

Focus is a separate issue. There's an electrical control for that.
It can be affected by temperature, humidity, etc.

"Jam rubber wedges"???

Some of the pricey "big CRT" sets have adjustment studs bonded to
the tube, and the yoke pretty much becomes a permanent part of
the CRT. But for anything up through 27", rubber wedges are
pretty much the norm.

"Get loose internally...with age"? It'll get loose just moving it
across the room to where it will be watched!

Some of them do get knocked out of alignment during shipping,
although it takes a pretty good hit when they are new.

Thanks for bringing this up - that's scary!

If you thought that was scary...

Most sets are now designed to last about 5 years, and then the
maker totally abandons support. It's all going to be moot in a
couple of years anyway, if the government has its way. Analog
(NTSC) broadcast has been targeted for termination, and everyone
must buy new (expensive) digital televisions with LCD or plasma
displays. Or maybe there will be set-top converters for folks
who want to extract the last dregs from their old sets.

 

[NSM]

THIS is how they build TELEVISIONS!?! Yikes!!! No wonder they go out
of tune so fast and so unpredictably. No wonder I have to re-focus a
brand new Sony that just came in the house! "Jam rubber wedges"??? I
thought that's how they loosened up or tightened up the handling of
NASCAR race cars!!!

If you don't like that you'll hate seeing how they align the doors on your
new car!

N

 

[Michael A. Terrell]

THIS is how they build TELEVISIONS!?! Yikes!!! No wonder they go out
of tune so fast and so unpredictably. No wonder I have to re-focus a
brand new Sony that just came in the house! "Jam rubber wedges"??? I
thought that's how they loosened up or tightened up the handling of
NASCAR race cars!!!

You obviously have no idea what you're talking about. This method
has been in use for 30 years so if it was such a bad idea some other
method would have been developed. After the wedges are placed they are
glued in place

"Get loose internally...with age"? It'll get loose just moving it
across the room to where it will be watched! LOL

Not unless you consider having an 800 pound gorilla throw it across
the room "Moving a TV"

Thanks for bringing this up - that's scary!

-CC

Scary is people who don't know what their doing trying to tell people
how to do their jobs. Do you stand over the shoulder of the bomb squad
and tell them to let you kick the bomb to see if it will go off?

 

[ChrisCoaster]

Well, both my direct-views are under a year old, so I guess I'd better
start looking into that converter if that's the case.

Of course a set will last 5 years with the Contrast left in the
jacked-up factory position!

-CC
(who will get at least 10 years out of his CRTs)