RCA ColorTrak FMR620WR (CTC-130A) From 1986

[colectorad]

This 25" tabletop set used to be my grandparents basement TV:



It's seen a lot of use over the years and attracted quite a bit of dust:



The flyback anode is shoddily zip tied to various yoke & neck board wires, leading to arcing:



I've since spread the wires apart by using a paint stick. This reduces the arcing noise.

On the main board, R506 & (to a lesser extent) R417 had charred solder joints:



I presume that this is due to the solder pad/trace being too small. I made sure to resolder/reinforce them.

--

As for other issues with this set:

1.) The top left corner convergence magnet was broken off and is missing (likely from a previous "servicing").

2.) The convergence is off in general. I presume the adjustment magnets are under the zip tie on the CRT neck. Can anyone confirm?

3.) The picture is shifted down and to the right. There are no centering potentiometers on this chassis. Has anyone installed their own?

4.) Stereo speakers without stereo circuitry. Does anyone have the schematic and/or the theory of operation for the stereo adapter?

[zeno]

This set may have a bonded yoke. In other words factory
adjusted for purity, tilt & convergence then glued in
place. See if its loose. Normally this set can not get out of
convergence.
If its not bonded they sold a magnet kit to replace the
magnetic tape on the neck if the CRT was changed.
Not sure what magnet is missing. ??

Arcing is strange. I cant think of an set after abt 1980
that arced at the wire. Just a few at the connector.

Centering could be done with taps but again would not
change without a failure.

Stereo decoders take the IF from the tuner & its basicly
a radio added.

put up some screen shots that will help. Do some with
NO color & some with. Also normal pix & a pattern.

[colectorad]

Originally Posted by zeno

This set may have a bonded yoke. In other words factory
adjusted for purity, tilt & convergence then glued in
place.

Nope, just a clamp.

Originally Posted by zeno

Normally this set can not get out of
convergence.

It's not "out of convergence", It's just "off" when compared to a CTC203AD5 of the same size.

Originally Posted by zeno

Not sure what magnet is missing. ??

It's the v-shaped corner convergence magnet that was glued to the upper left side at the back of the CRT.

Originally Posted by zeno

Centering could be done with taps but again would not
change without a failure.

I'm thinking it's a design flaw.

Originally Posted by zeno

Stereo decoders take the IF from the tuner & its basicly
a radio added.

Yes, but how does the adapter reach the TV speakers? How does the volume control work?

Originally Posted by zeno

put up some screen shots that will help. Do some with
NO color & some with. Also normal pix & a pattern.

I'll get to this later. A 4:3 test pattern DVD would do me wonders.

[Findm-Keepm]

Originally Posted by colectorad

[/url]

The flyback anode is shoddily zip tied to various yoke & neck board wires, leading to arcing:



I've since spread the wires apart by using a paint stick. This reduces the arcing noise.

That needs a good dusting - lead dress is not the main problem with arcing. More likely the dust. Vacuum + soft bristle paint brush and try it form there.

You can lay a clean 2nd anode lead against anything without arcing - 40KV wire doesn't arc - the dust is providing a second path for the HV.

[zeno]

The V magnets are correction magnets. They are over the area
where the purity is off after the set-up. You can use any small
magnet, a refrigerator door gasket magnet works fine. But
for convergence on the sides you bend the yoke then jamb a
wedge in place. For now its best NOT to mess with it til you
can put up a pattern & screen shots. Could be other things
like the CRT.
For now bring it outside & blow the dust out. Remove the HV
lead & clean everything along the wire & the uncoated glass
around the anode button with 91% isopropal alcohol. Let
dry then try it.

73 Zeno

[TVTim]

The wisdom and knowledge on this site never ceases to amaze me.

[colectorad]

Here's the best I can do for photos:

The worst of the convergence is at the top right side (where the v magnet is missing):



Some full shots from my 16:9 calibration disc (excuse the interference):



Other A/V sources:

[Findm-Keepm]

Unfortunately, your image host has a pop up that requires a download, so I'm not going there...

Flickr, photobucket and imgur are better, and don't badger folks with popups that starts a download of unneeded junk.

[colectorad]

^That's not a pop-up, it's a banner. The photo is at the center of the page. If you can't stand those banners, an app like this one will remove them.

[Findm-Keepm]

Originally Posted by colectorad

^That's not a pop-up, it's a banner. The photo is at the center of the page. If you can't stand those banners, an app like this one will remove them.

Oh, it's a popup, from a script. ScriptTrak says the site runs 7 scripts, 4 of which are vital (necessary). I'll just follow from VK.

I run AdBlockPlus already.

[colectorad]

^Then why am I not receiving any pop-ups? I trust you're running Windows.

[colectorad]

Also, Imgur uploads:

[zeno]

OK the conv is off in the center & you wont get the sides
right without the center. CRT looks strong, grey scale off a little
try a little green.
So why is it off ? May have always been like that ? Another
theory is the neck magnet has changed by sitting in the same
place for 30yrs by the earths field. If it were me I would
mark the magnet so you can put it back then cut the tie
and try adjusting it. Without a set of rings thats about all you can do.

73 Zeno

[zeno]

Found the RCA part number for magnets.
36157300008
this is not the usual 6 digit format so it may be a drawing
number.

73 Zeno

[colectorad]

After creating a 4:3 test pattern DVD from here, I proceeded to make adjustments.

I did not cut the zip tie from the convergence magnet. It was loose enough to slide off and proved useful for clamping down the magnet after the packaging tape was removed.

The static convergence was not originally calibrated. Instead, they chose to generically set the seam of the magnet to the 12 o'clock position on the yoke assembly, probably to speed up the assembly process. I found it looked best between the 7 & 8 o'clock positions:



^The upper right corner is still bad. No amount of yoke adjustment would improve it. I'll need to make a v magnet at the very least.

Then, I adjusted the green bias:



Note the powdery blue distortion at the upper left on the white and yellow, it's not dust and it's not on the outside of the CRT:



While the static convergence adjustment did greatly improve the horizontal centering, the vertical centering is still off:



^The yoke doesn't go up any further. It needs to be adjusted electronically with modification. I just need to know where to install a variable resistor, as well as its' ohm range and any supplementary components.