Restoring CT-100 #B1111566

[ChrisW6ATV]

James, thank you for the interesting notes about the capacitors. The ones in my set are mostly dated in the mid to late 1960s if I am reading them right (6807 in the lower picture above, for example).

Phil, I will use alcohol and see if that gets things cleaned up. Your CT-100 looks very nice inside its HV cage.

[ChrisW6ATV]

More progress this week so far: I cleaned most of the components in the HV cage, removed all of that white silicone, and replaced more of the incorrect or poorly-replaced parts.

Silicone has been removed, and the focus-rectifier diode has been taken out. I chased all over for a replacement plate cap for the 1X2 tube (not yet installed), then later found I had one in my parts box already!



You can see the two "bloody stumps" of the cut off filament wires to the 3A3 HV rectifier here, as well as some of the dirt and corrosion before I cleaned it up.



Here, the replacement of the HV filament winding is in progress. I installed two loops around the flyback core; we shall see if this is appropriate for the wire I used.



A few more parts to install or replace, then some Deoxit on the controls and tube sockets, and I will be ready for the first power-up, I think.

[ChrisW6ATV]

The HV cage is done, unless I find problems when I apply power.



As I work on this set, my appreciation for the engineering of the NTSC system and of these first color TVs grows and grows.

[ChrisW6ATV]

[Aussie Bloke]

Absolutely splendid resto job mate!!!

[IsthmusTV]

Wow, Chris! Congratulations!! That must feel great.

How fitting that you got a shot of the Queen's colorful flotilla....

73,

Clark, K9OA

[miniman82]

Nice work! Always nice to see another one resurrected from the grave. Looks like you have a bit of an overdrive line, does reducing hte drive control make it go away? I had to change the value of a resistor in the drive circuit to get my drive line to go completely away, because it wasn't shunting enough of the signal to ground.

[old_tv_nut]

A thing of beauty! Congratulations!

[Sandy G]

Wow...You technokings NEVER fail to well & truly impress a bumpkin like moi...

[Glenz75]

That looks pretty dam amazing I have to say, a real transformation
I like that CRT test jig you have the chassis connected to, going by the colour bars on the screen its pretty darn good! Congratulations. Cheers.

[Phil Nelson]

Ausgezeichnet!

It's fun to use a screen shot of a contemporary event, which will fix the moment in time.

Phil Nelson
Phil's Old Radios
http://antiqueradio.org/index.html

[ChrisW6ATV]

Thank you all for the nice compliments and comments. I had tested the CRT last year when I got this set, but I did not know if it was going to be usable until I hooked up the chassis, but it is in pretty decent condition. Those pictures are with only minimal knob-twiddling after the restoration work I did on the chassis. Beside the good 15GP22, the happiest part for me is that the HV cage did not spark and arc all over the place after all the work I had to do in it.

Originally Posted by miniman82

Nice work! Always nice to see another one resurrected from the grave. Looks like you have a bit of an overdrive line, does reducing the drive control make it go away? I had to change the value of a resistor in the drive circuit to get my drive line to go completely away, because it wasn't shunting enough of the signal to ground.

Nick, the horizontal drive is set to minimum now; the drive line and non-linearity get worse if I increase it. The catch so far, though, is that my HV was about 17KV (adjustable downward only) before I reduced the drive, so now it is lower than that and the picture is dimmer and blooms even at relatively low contrast settings. I verified my coupling capacitor is .0015 (I just replaced it), so I need to check the values of resistors and other parts in the horizontal circuits (anything that I did not already replace) to look for most-likely causes of the low HV. This set started with a bunch of parts in the horizontal and HV circuits (all replaced in the past) that did not match the RCA or Sams schematics, so I replaced them all with the original values, but maybe those changes were done for a reason?

I wired the set in its original "early version" configuration (except that I made the change to allow a 6BK4 HV regulator), but I will probably go ahead and make the changes described by Pete Deksnis (and your HV-regulation mod) as well.

[miniman82]

If drive is at min and you still have a drive line, you'll have no choice but to make changes to reduce drive till it goes away. It's gonna be the usual juggling act- horizontal lin vs drive, vs width vs HV, ect. Tweak it till it's right. You can do what I did and unplug the anode lead and regulator top cap, then measure HV with the probe. Then tweak till you are able to get decent HV, and plug everything back in. If it makes good HV then drops when you plug the regulator back in, you'll know you need to twiddle with the reg circuit.

[Einar72]

Good job, Chris! Hope the back fits!

[ChrisW6ATV]

Thanks, Einar. Yes, the back fits fine too!