Deader than dead CTC-9
 

Recently acquired this RCA CTC-9 metal cabinet set, yoke is charcoal along with the horizontal width pot. Knobs are gone and the cabinet has a nice scar on top right corner.

Hope to get it glamed up and working as a daily driver.

More pics

Great project-some real sharp repairs on that set! Proves that there were always hacks. Lots of fun to bring something like this back from the brink.

I have a CTC 11 which was similar. It was great fun solving the problems. The if coils had disintegrated and found exact replacements at a nearby electronics surplus.

Patience and dedication will see you though! :thmbsp:

If the width pot is the one with the green wire and the brown half a lamp cord wire to chassis, and you judged it with your eyes instead of a multimeter then you may find that it still works...That one seems to use black plastic to hold the resistance material and terminals (instead of the brown phenolic of the other pots) and is likely still just fine.

The yoke is not so much charcoal as disintegrated plastic. The early plastics used for the outer shells on most yokes before the mid 60's were very unstable and will rot away on their own...This even happens to unused mint in box NOS specimens.

The windings and important core parts look fine and are probably still safe and functional. The shell can be recreated with a little effort with modern plastics. The part that usually rots away only acts as a mount for terminals as well as a guard to make it difficult for a service tech to accidentally grab those terminals with the set running (it also is supposed to be the grab handle to adjust the yoke).
You want to avoid touching the yoke terminals if the set is powered on...The meanest shock I've ever gotten from a TV set was a CTC-15 clone that I touched a portion of the yoke winding where the insulation was bad...That is the only time I can remember my 'let go of this' reflex kicking in full strength...

I measured the component out of circuit and it will need to be replaced as the carbon track is ruined.

I am fairly certain that yoke is cactus. A ring test should prove it. I've seen yokes looking like that before and they were all crook with shorted turns.

Working on one right now. Bad Bubblebees in the horizontal circuit. Nasty things that they are.
Dump the Black Beauties as well, and of course paper.
The set is like new now. Not to rub it in, just to say I feel your pain. Pix to follow...

The 106305 Deflection Yoke is a Y-107 according to my 1983 Thordarson TVPG-15 book. The Sams 459, page 11, doesn't cross it.
Check the horizontal centering pot on the flyback and the brown dipped caps in the vicinity, as well as the 56pF 6KV disc.
Mine were all off and leaking. The current went way down after replacement.

Good tip on the disc, never though to check it.
I had to replace the horizontal width pot as the fine wire was all tangled up inside and believe it shorted out taking the resistor on the back of it and the horizontal winding on the original yoke with it.
I also replaced the two caps in that area. I now have HV but it needs to be reduced.

Progress so far;
HV is 29+KV and turning up the horizontal makes it go higher.

Chassis is back out for resistor checks and cap replacing
Starting with the horizontal board and vertical board

Yep, looks like you're on track (sorry, couldn't resist!) Here most folks have trouble with HV being too low...

May want to get the HV reg working first. If you run it that high too long you may damage the CRT and or flyback with internal arcing.

Wow that seems like run away hv,+29 kv if the fly can put that out it should last a while provided it is lowered.

Timmy, when you adjust the HV down to 25K, you will actually be putting more load on the flyback. Remember, the total load on the flyback is the sum of the current drawn by the CRT and the current drawn my the HV voltage regulator. As the scene on the CRT gets brighter, the CRT draws more current while the voltage regulator draws less and vice versa. The whole idea of shunt regulators is to present a constant current load to the flyback/HV rectifier under all screen brightness levels.

ALL caps are suspect after another remote session today. I hope you have a good cap checker that has leakage & rated voltage like the Sencore. Check at the linearity coil. Brown caps were all leaking at 200V & 600V ratings. Try not to use any yellow caps in the AC current circuits.:nono: HV bypass is OK but not current. I know, as see you are using Orange Drops, but I am speaking to the uninformed.
BTW same tangled mess in the pot.
I guess your yoke is OK or is that another one?
Keep us posted!:thmbsp:

The original complaint was that the horizontal wouldn't hold/breakup if close to lock.

I replaced some bumblebee caps in the horizontal section. Great go home.

Next is a call that the vertical is bad. I go back and fix the lack of vertical/height.

The next call is that there is no sound, just a faint buzz at high volume.
It was then decided to solder all ground supports for the boards and any suspicious areas as well.

I note that something is noisy in the audio detector area. Tapping there produces lots of loud noise in the speaker. Okay, change the 6DT6, nope. Narrowed it down to A11.

While I'm in there, I take out the very microphonic A11 the quadrature trap. Then I noticed it. A piece of half clipped wire still attached to the center leg to one of the outer legs, shorting the winding. This was factory, as it was still connected to its master wire. Removed, reinstalled and aligned. Nice audio. Shame RCA.:nono:

Let's check the flyback as it looked like a lot of wax was on the bottom of the box, not unusual for a 59 year old TV.
Gahhhh! there is the 56pF cap with burn marks across the ground side of the cap from the bottom 22MΩ resistor. Replace what I have with me, clean what I don't. I never could get the H centering pot to move. Let's look at that. Frozen or should I say burnt in place.

A 90 mile round trip ride later back to my house, I have one. Need some resistors that are burned up in there too. Remove and replace. All looks good. Tested and all is good again.

Now let's look at some more caps and test for leakage. Remove, replace, reinstall chassis.

It's now around 1AM. No video. Well there is. Out of brightness and focus with a blue tint. The CRT socket is apparently intermittent. Next visit We're done for the night.

Now to this Oct 1st weekend. I made up a socket assembly from a bare short clipped unit. I found wire to match the original colors, just because. Dissembled the TV and benched it to look at the dissembled socket by drilling out the rivets. One of the factory solder connections to something blue related (I don't care at this point) which was never done. Solder it. Shame RCA.:nono: Check the focus connection. All fuzzy white, with a corroded pin and receiver. Clean Clean Clean. Replaced the chassis and all is good.
Still seems a bit narrow though. The vertical is not filling the CRT as well. Boost Voltage. Check the B+ you say. A bit low. 340 something volts instead of the 385V. Before the filter reactor the same. Line voltage is optimal. :scratch2:

It's late again..... Parts on order for next weekend's failure adventure.:sigh:

All this on a TV that looked good after the first repair...

Damn that chassis looks factory fresh! Can't say the same about mine, it's a little rusty and dirty.

That's a pretty good rap sheet, I'm feeling mine is gonna be a similar way, I don't hold much hope for the flyback lasting any length of time. But you never know.

The fly looks good, and IIRC you (or was it the other guy?) had HV. If it looks that good and works then there are a couple of things you can do to ensure it lasts.

First, go through the complete horizontal setup procedure and make sure to minimize the horizontal cathode current. The schematic probably quotes a max somewhere around 210mA when adjusted correctly it should never go above 200mA and 175-195mA is the typical minimum achievable. (this can be influenced by line and B+ voltage so feeding it a constant optimum line voltage through a regulating isolation transformer is a good move) If you can't get it more than 10mA below the max spec you may want to go over the parts in the horizontal section with a fine tooth comb to improve performance.


Second, if the first steps have been successfully run the set for intervals between 30 min and 4hours then power the set off and quickly feel it's temperature if it is close to body temp or cooler your good, but if it feels uncomfortably hot add some ventilation holes and or a cooling fan to the HV cage.


I've run sets with worse looking flys for years on daily driver status with this method and had 0 fly failures from it.

It's something like that, I'm at the station right now but I have the factory manual at home, I have to dig out a meter capable of measuring that voltage, I have one of those old ones you can plug into the output tube socket on the old b&w sets but it doesn't not list 6DQ5 on its manual so I do not know if it will work

She's a real beauty. Takes me back to the 70's when I was servicing these "old" TV's. Old, if old is 20 years.

Didn't see if your yoke was any good or not. Let me know please.

Like the man said, check all the caps in and under the flyback cage. Check the 6DQ5 current.:yes: The 3A3 plate cap was burnt and changed to a Millen ceramic type. Check your Globar, this one's fell apart. Fuse the primary and change the N fuseholder to an AGC type. I don't do bayonet fuses, wire links of #28 or Belfuses.:nono:

BTW since changing caps in the flyback area, the power transformer runs a lot cooler.

As electronic m noted in a previous post that leaving the hv to high does run the risk of arcing within the crt and damaging both the flyback and the crt. :smoke:

Enjoy the free chest and :banana: x-rays.
Better get that HV under control.
This leads me to the following report.

ALL of the resistors in the HV regulator circuit were waaaay off. Changed them all out with some 1% resistors as seen in the picture.

The focus resistors were even worse. 22M was like 43M. All were replaced with series-parallel 1%'ers to make up the high resistance and wattage values.
Caps in the HVR and the defective burned one were replaced as well.

After futzing around with why the width was shrunken. The 6DQ5 was replaced a few days ago by the owner. He reports full width and 710V of boost.

I placed an additional type AGC fuse & fuseholder in the existing holes in the top of the chassis. Changed out both the type N fuse & fuseholder for AGC. Now both the primary and secondary is fused.

This weekends adventure is fixing the vertical linearity. Everything :scratch2: has been replaced EXCEPT for the components in the yoke.

So I'm go'in all in.
Enjoy some pix.

Don't X-ray your banana too much otherwise ya won't be able to have kids. :D

I couldn't find any coconut smilies....

After 20 yrs with TV's in my lap I still wasnt shooting blanks. Just another
government scare tactic...............

73 Zeno
LFOD !

Progress update:
Now have a pic on the screen still yet to change electrolytics and do full setup-convergence. The HV and cathode currents have been tamed and the set doesn't smoke or get hot even after 30min on.

Here's some progress pictures.
Next on the list is power supply caps

Nice work! Some adjustment of the purity, convergence, greyscale, add in some color demodulator action and it will be a watcher.

I plan to do the power supply filters as I have hum bars in the picture.
I still have not solved the lack of drive issue but we will see what it looks like after power supply caps.
I'd like to get all the focus, centering and linearity issues fixed before doing color-purity-convergence setups.

-will.

Purity and static convergence should not be affected by centering and linearity...Focus could disturb static convergence a bit. Dynamic convergence is susceptible to deflection adjustments.

Good news on the CTC-9, getting good progress, power supply caps done.

Looks amazing, Tellyrescue!! Marge's hair is perfect! :D:D