3 Days left to donate for a chance to win a RCA CT-100 Color Set
 

3 Days left to donate for a chance to win a RCA CT-100 Color Set or $2,500 in cash in the 2021 Early Television Museum Sweepstakes.

The drawing will be live, as part of the Monthly Online Meeting of the Early Television Society, this Saturday, October 23, at 8 EDT.

Get a bonus of 40% more tickets for your purchase. If you have already bought tickets, consider getting some more.

We have sold over $10,000 in tickets. The grand prize is a RCA CT-100 color set, with a good CRT (or $2500 in cash). You can buy tickets here:

https://earlytelevision.org/2021_sweepstakes.html

Our fall swapmeet will also be on the 23rd, from 10 AM to 2 PM EDT. The meet will be in the parking lot of the museum, at 5396 Franklin St. Hilliard, OH. The museum will be open too, so you can tour it while you are at the meet. Hope to see you then.

Who ended up winning?

Some dude in Florida who's name escapes me.
I wonder if he took the set or the money behind door number 2.

I'm the dude. Took the set. 15GP22 still under vacuum and shows fair emission on my CR7000! Getters still good. Chassis appears to be physically complete but not restored and electronic condition of parts unknown. Cabinet somewhat rougher than obvious in pictures. Happy to have won! Also enjoyed a nice 2,000 mile road trip that included the Carolina and Virginia autumn vistas.

Congrats. Hope you keep us informed of the restoration progress.

These are fun sets to work on. I finished someone's half done resto on my CT-100 and did a full restuff of the caps in my 21CT55 ( CT-100 chassis with factory sweep mods to drive a 21AXP22 CRT) granted most were bakelitized cardboard so I got similar wax caps and restuffed those. I did the 21 a few months before the CT-100 and was so sick of restuffing that I didn't even try to hide the yellow caps the last owners put in it (just cleaned up all the J-hooks on J-hooks, and bad peaking coils/odd mix of replacements).

On these sets if the IF acts like it needs an alignment you can often avoid doing it by going over the IF resistors for off tolerance parts with a fine tooth comb then adjusting the channel osc slugs in the tuner. IIRC I had to make my own adjustment tool for it out of mechanical pencil bits...good times.

Thank you! The Grand Prize CT-100 will have to sit for a while, sadly. I'm currently in the process of getting a whole house wiring project underway. Winter in Florida is like summer up north. It's the time to get projects done that require good weather, such as working in the attic, where it is impossibly hot in summer. So, I have to get this done while it's "cool" (less than an inferno), then I can look forward to the CT-100 project next spring as a "winter" (summer) project...with lots of air conditioning!

All the CT-100 parts will be stored in clean, climate controlled fashion until then. I'll circle back here to provide updates when there is something to report. Best wishes to all until then. -Bruce

Congratulations! I'm glad somebody suitable actually took the set. I too got
a CT-100 from the ETF.

I decided not to do a cosmetically correct restoration, mainly because
I decided that restuffing all the "can" electrolytic caps would be too dangerous to
nearby parts.

I removed the orange selenium rectifiers and mounted the filter caps and dropper
resistors on epoxy tag boards in the cage. I also added several additional fuses.

I had trouble with focus voltage stability and finally used a long chain of 150 volt
Zeners to regulate it.

This set has 82 total adjustments (counting only one channel in the tuner). That includes all the yoke and purity coil physical motions. And every one has to be right!

I found that replacing the myriad bad "white" peaking coils with even the RCA specified
alternates may not be optimal (due to differences in intrinsic parallel resonance frequencies). I bought several different coils of the specified inductance and used the ones that gave the best frequency response. The 6.8 mH one in the Q channel is clearly the wrong value; 3.3 mH is more like it. It turns out that 82 adjustments is one too few: you need one more adjustment in the color matrix to get it exactly right.
The specified values are the nominally correct nearest standard values, IF the feedback resistors in the adders are all exactly the same. I found that getting the correct color gradation in the violet through magenta range while all the rest was OK took a bit of tweeking the matrix. This can be done by looking at color bars on a scope
to match the pattern in the manuals.

Getting all the RF-IF-color amp alignments exactly right is critical for the
best picture. Its possible to get all the colors exactly right and no ringing in the
picture at all if all those adjustments are correct. See the pictures I posted in my restoration thread.

Finally, and most inauthentic of all, and entirely optional, I added a parallel combo of
a 100K resistor and .001 uF 6 kV ceramic cap in the leads to all three CRT screen grids. The 21CT55 has the resistor to protect the CRT cathodes in case of an arc. I added the small caps as just the resistors caused some minor color shading problems. I did this after original my CRT got slightly gassy and arced, destroying the red gun. It took two years to find a good replacement CRT.

Congratulations. When the time comes, I will enjoy seeing your restoration progress.

Thanks, everyone. I'm eager to get to it and sorry there will be a delay. Sadly, I've got to do these other household things while the weather allows.

We've had some family crises this year (including the passing of my father) that have prevented getting to several big household things. Thus, the restoration projects I've been really eager to do have been pushed even further back. I suspect many on this forum have similar troubles finding time. Hopefully, time will be available by spring.

Thanks dtvmcdonald for your tips and pointer to your CT-100 restoration in the Tech Forum. I'd not spent any time browsing that forum previously and was delighted to find all those details there.

Believe me, I'll be carefully compiling and reviewing every CT-100 restoration tip I can find before tackling the project and during the project. It will be terrific to have the benefit of all those prior experiences to know what to look for...and look out for.

Thanks to everyone who has taken the time to document their experiences. I will try to do the same when the time comes.

I also have a CTC-5 Deluxe Wingate, mostly restored by a previous owner, with a good 21AXP22, that I intend to go through stage by stage before tackling the CT-100. That should be a nice warm-up for what will almost certainly be much more of a challenge in the CT-100.

Watch for updates in springtime. Best to all until then.

-Bruce