Several years ago Bryan Tennyson discovered what was thought to be a CTC4 Director set. It was found in a leaky shed in Meridian Mississippi. According to what Bryan told me it had been sitting in this wet shed deteriorating for more than 30 years. It was offered to me for the cost of shipping it to Milwaukee. When I received the set, Ed Reitan informed me that it was a very rare Hallicrafters CTC4 clone and that it was only the second one known to exist.

The set was in the worst state of deterioration I have ever seen. It was literally falling apart and disintegrating. But due to the rarity of the set, the massive amount of work needed to restore this set, was warranted.

I have nicknamed this set the "Lazerus" Hallicrafter because it has literally been resurrected from the dead.

Because of the immense amount of work it took to restore this set, the story of it's restoration is far too voluminous to present in any forum such as VK. The entire story is told on my web site and can be accessed via this link.

http://antiquetvguy.com/Web%20Pages/The%20Restorations/1955%20Hallicrafters%2021CK801M/1955-Hallicrafters-21CK801M.html

There are currently 49 full resolution photos posted on my web site, with still more to come. I hope you will find the story of the restoration of this set enjoyable, entertaining and enlightening.

I will leave you with a teaser of just two photographs to peak your interest. A before photo of the set in the condition I received it, and an after photo of the completely restored set.

OOOhhh......me likey!

:banana::banana:

Wow. Just "Wow". (grin)

Wow! What a beauty and I enjoyed your write up!

Hats off to you! That is the most intricate, and significant restoration (and might I say ACCURATE), that I've ever seen, and I've been a TV collector and historian for over 30 years. I can't wait to hear Ed's praises on this too! I'm sure he's very impressed with that accuracy. I had a "new cabinet" made once for a GE 15" color set 15CL100, and it was somewhat close to correct, but NOT a true rebuild of the exact cabinet. I can't even imagine the dedication it would take to do something that big....

Charles

Very nice work, Bob

An inspiring tale. Crumbled cabinet, fire, mud daubers -- something for everyone!

In these basket-case stories, it's alway interesting how many components can be salvaged. Some people might have taken one look at that chassis and left it for dead. You replaced many things, but a number of the original components survived and are still working well.

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

Wao, this is just too much. It's the only TV resto i've ever read that rises to the lump-in-throat, tear of eye that's reserved for a vintage aircraft's or steam locomotive's restoration and remaiden.

:rockon:

Hey I have another TV in that condition if you want it :). Fresh out of a leaky basement, back rotted off, all that good stuff. I don't think it's rare though.

Seriously, though, nice work.

now this is the definitive way to restore something.amazing account of the process and a must read for us all.once again,the master at his craft!

That is one nice nut......

Hello Bob!

Very impressive work, especially the woodwork. I have visited almost your whole website this afternoon :thmbsp:

What was the condition of the mains and the flyback transformer when you started restoring the set?

Greetings Josef

Extraordinary!! :yes: Great info about the restoration on your website, too.
Thanks for sharing!
Kevin

That must have been pretty close to the "Tail-End" of Hallicrafters' TV exploits...They, and National, another "Old Line" radio company, got in on the post-war TV boom...National didn't fare too well, but Hallicrafters kept it going into the early color era.

Hello Bob!

Very impressive work, especially the woodwork. I have visited almost your whole website this afternoon :thmbsp:

What was the condition of the mains and the flyback transformer when you started restoring the set?

Greetings Josef

Flyback is a replacement, and works very well and it runs nice and cool. I believe the original flyback design was not very good because many CTC4 chassis have replacement flybacks.

The power transformer is likely a replacement also. The positioning of the lead wires from the transformer do not look the way they would look if it was a factory original transformer. Power transformer was very rusty, but I cleaned off all the rust and repainted it with black enamel.

Happy that you enjoyed my web site which is still a work in progress.

An inspiring tale. Crumbled cabinet, fire, mud daubers -- something for everyone!

In these basket-case stories, it's alway interesting how many components can be salvaged. Some people might have taken one look at that chassis and left it for dead. You replaced many things, but a number of the original components survived and are still working well.

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

Thanks Phill,
You are correct. Even a basket case can be made to function again if you have the patients and desire to address all the issues one at a time. It also helps to have a diverse set of skills and friends that can help you when there is something you need to farm out. IE: the creation of a replica back on a CNC router table, or somebody in the electroplating business. My skill level in electronics is at best hobbiest level. Many of the guys here are certainly light years ahead of me when it comes to electronic theory, but even a guy like myself, can get buy with the help of the rest of the community, for which I am humbly greatful.

A heartfelt thank you for all the kind comments from all of you. It is humbling to say the least when you get compliments from people who understand this area of electronics so much better than I do. But the neet thing is that the process of understanding this stuff is an evolutionary process. And little by little I pick something up from you guys that helps me through the more difficult issues. The great part about this community of tv nuts is that we are helping to pass along our skill set to others.

Thanks and thanks again!!!:thmbsp:

Wow Bob, that is just amazing work, even the inside looks factory original!

You basically built a cabinet from scratch!
Have you asked Ed Reitan what number is stamped into his cabinet (where the 2 is on yours) If you have the number two set made it's unlikely there were many produced.

The photos speak for themselves. What a set!!

Ya Done Good !!

You should be very proud of your work, Bob! That Halli received the best of care in your ER!

Even the Hallicrafters book don't show the 21" TV... You know more than chuck Dachis !

Hats of to you BOB nice work.

Amazing,just amazing...congratulations!!

Kudo`s # 24 amazing project.

Wow. Just wow. :)

How's the alignment holding up? I should probably go through it again at some point, that first go around was kinda weird. Picture looks pretty good for now though, I'm impressed!

I wanted to check the HV setting this morning. And while adjusting the HV control (burried above the power transformer) the raster suddenly went dead. Sound but no picture. I fiddled and fiddled with no luck finding the problem.. So....disconnect everything, unbolt the chassis, and drag the chassis downstairs to the basement lab.

IN the process of trying to find the no-raster problem I discovered that all my B+ voltages were running to high. And upon investigation, I discovered that I screwed up. Not very unusual, I screw up all the time.:yes:

I found that I have the B+ dropping resister wired improperly. I will fix that tomorrow. So I put the input AC on my variac and brought the line voltage down to 100vac which is now giving me the correct B+ So then I figured that with the B+ at 350 where it belongs I should reset the HV pot again. In so doing my hand bumped the end of the delay line and VIOLA I had my video back. There was a bad solder joint where the delay line lead is soldered to the terminal strip. Somebody had just tack soldered the lead on the terminal lug and the lead was never hooked through the hole in the lug.

So tomorrow I will address the issue with the B+ dropping resistor and put the chassis back in the cabinet and hopefully, I will be done for good this time.

Wow, Bob. That restoration about tops the cake. I'm very humbled by your level of dedication, patients, and attention to detail. :yes:

Even the Hallicrafters book don't show the 21" TV... You know more than chuck Dachis !

Hallicrafters is a mysterious company. I have had several radios (home radios; not ham sets), which have non-existent model numbers in any Hallicrafters lit. Someplace I also have a Hallicrafters 9" color TV with built-in VCR; made in the 90s or so. It's really a Funai, but I kept it from the trash due to the badge.

Charles

Absolutely first class work. Outstanding. Don

Absolutely fabulous work, Bob! I'm proud to call you a fellow Wisconsinite!

-Clark

Wow! That is perhaps the most impressive level of craftsmanship I've ever seen go into a TV restoration.

Seeing the before picture it is amazing that there was enough left to make back into a complete TV set (even with all the newly fabricated parts).

I'm also surprised that the original necked CRT didn't have the phosphor blown off; how do you think that would come to be?

Could have been cracked to begin with, then fallen off. That's the same way rebuilders do it- crack the glass, then twist off the gun. We just did a 15GP22 that way at Bob's house not long ago, it's unnerving but works just fine. Turns out the gun structure diffuses the incoming air, so the phosphor isn't in any danger.

Another "Bob-Restore" that continues to amaze us all! Your previous 21ct55 was hard to beat but this one was much more challenging. So what's next? Speaking of 21CT55s, mine needs a reproduction pencil-box and control door. Think you can fab this from scratch? If so, send me your bid......just kidding. Tom

Now thats what I call a 'ground up' restoration! :yes: Fantastic transformation Bob, I take my hat off, a real credit to you. :)
Cheers
Glen

I'm also surprised that the original necked CRT didn't have the phosphor blown off; how do you think that would come to be?

It's a 21AXP, it could have been down to air before it got necked.

Bob, I never dreamed this set could be saved and that is the most AMAZING restoration I've ever seen on any piece of electronics.

Unbelievably awesome, Bob!! You have every right to be proud of this!!!

Looks great!

Absolutely fabulous work, Bob! I'm proud to call you a fellow Wisconsinite!

-Clark

Nice clock Clark!:thmbsp:

Wow! That is perhaps the most impressive level of craftsmanship I've ever seen go into a TV restoration.

Seeing the before picture it is amazing that there was enough left to make back into a complete TV set (even with all the newly fabricated parts).

I'm also surprised that the original necked CRT didn't have the phosphor blown off; how do you think that would come to be?

May have been a leaker crt to begin with. On the other hand the shadow mask is not very porous and is probably capable of blocking the inrush of air to some extent in a traumatic event. Also when you crack the neck of the tube, the broken remnant is held in place by the powerful vacuum inside of the tube. IT is not easy to pull the broken piece off until the vacuum has been mostly released. It's like when we use a hot wire to sever the neck in preparation for rebuilding a tube. You can't pull the two neck pieces appart until there is no longer a vacuum inside the tube.

EDIT:
OOOPS, I see this has alredy been answered by Nick.

Bob, I never dreamed this set could be saved and that is the most AMAZING restoration I've ever seen on any piece of electronics.

Bryan,

I am happy that you like the final result. If it wasn't for you, I never would have had the opportunity to bring this rare set back from the dead. You did both me and the collector community a real service by saving it. You did good man, and I thank you on behalf of all tv collectors everywhere for rescuing it.

Damn. Now I know that ANYTHING is possible. That set looks absolutely beautiful!! Omedetou! Hontou utsukushii da na!!!

Somebody must have purloined the "Hallicrafters" name from the annals of history...

Damn. Now I know that ANYTHING is possible. That set looks absolutely beautiful!! Omedetou! Hontou utsukushii da na!!!

Mark, if you've been into anime long enough you should know that anything is possible there, but when the impossible happens in the real world it is either really awesome or really disturbing.:D


It is fitting that halicrafters had a CTC-4 clone in their line as, if I'm not mistaken, the tuner RCA and most clones used was a licensed halicrafters design.

This makes me really want to start getting that glorious lolipop color on my CTC-4 to work right.

Mark, if you've been into anime long enough you should know that anything is possible there, but when the impossible happens in the real world it is either really awesome or really disturbing.:D
"The difficult we do immediately.
The impossible takes a little longer."

U.S. Navy Seabees motto.

:cool:

Hi Bob, I'm curious to know how you resolved the dropping resistor situation. I also would have inserted it between the 4.5 amp fuse and the rectifiers, but upon looking at the schematic for my 4, I see that it would not be the best place to put it. I too am having voltage drop trouble with the original rectifiers, and need to replace them with 1N4007's, or equiv. B+ is about 345-350, not the 380 specified in the RCA lit, and when I crank up the variac the improvement in the pic is notable.
Thanks!
Kevin G.

Hi Bob, I'm curious to know how you resolved the dropping resistor situation. I also would have inserted it between the 4.5 amp fuse and the rectifiers, but upon looking at the schematic for my 4, I see that it would not be the best place to put it. I too am having voltage drop trouble with the original rectifiers, and need to replace them with 1N4007's, or equiv. B+ is about 345-350, not the 380 specified in the RCA lit, and when I crank up the variac the improvement in the pic is notable.
Thanks!
Kevin G.

Kevin,

I will have to get back to you in a couple days. I am going to relocate the dropping resistor in the lead that connects the out going leg of one of the half wave diodes to the main filter caps. I will post a drawing with the placement and the value of the dropping resistor when it is finished. That said, replacing the inefficient sleniums will bring back your B+ to a much higher level. It will probably be too high like mine is now.

I have been nusring a very nasty case of the flu for 4 days now and I think I will be back up and around in another day or so. Watch for a future post.

Dah-Yum, Bob, take care, 'n' get better soon ! DON'T get out & Horse Around the 1st day you feel better...Take it easy a few more days & let it get good 'n' gone...

Bob, This restoration of an interesting set which was made in small numbers if that was totally heroic. In my book should be one of the Top 5 early Roundie restorations of the year if not the decade. Beautiful job.

Hi Bob, I'm curious to know how you resolved the dropping resistor situation. I also would have inserted it between the 4.5 amp fuse and the rectifiers, but upon looking at the schematic for my 4, I see that it would not be the best place to put it. I too am having voltage drop trouble with the original rectifiers, and need to replace them with 1N4007's, or equiv. B+ is about 345-350, not the 380 specified in the RCA lit, and when I crank up the variac the improvement in the pic is notable.
Thanks!
Kevin G.

Sorry it took so long to get back to you Kevin. I have had the flu and a million things to do and I just got to figuring out the placement and value of the resistor needed.

This is what I have done. Using clip leads I inserted a 1K 50 watt wire wound pot into the power supply circuit. The best place to insert the droping resistor is on either one of the leads of the power supply choke. I chose this location because it is the best place to insert and have the droping resistror effect all of the various power supply voltages.

While adjusting the 1K 50W pot, I monitored the B+ supply voltage and when I reached 350V (the specification on the Sams schematic) I recorded the voltage across the pot and the current through the pot. I dropped 72 volts and had 440ma currrent. I calculated about 32 watts of heat energy will be generated. Then I disconnected the pot and measured the resistance. 150 ohms. I have ordered some Vishay 50W 150 Ohm Aluminum clad power resistors from Mouser. Mouser Part# 71-RH50-150 at $4.67 each. I will mount the resistor somewhere on the top of the chassis where the heat will be easily disipated.

If you want to go with the 380v B+ as specified in the RCA print, then these values are what you will need. 70 ohm 20 watt, gives me 380v B+ in my set. My set seems to be functioning about the same at either B+ voltage. I get a nice full bright raster at either 350v or 380v.

If you replace the original stack rectifiers with 1A 1000piv diodes I would guess you will need to drop a similar amount of B+ voltage to get the supply voltages back within specification. Good luck, and I will post the photos of the mod in a couple of weeks after the new resistors arrive and I install them, so you can see how I did it.

I think I might try finding some NOS selenium stacks for my CTC-4 Director, that's the easiest way to fix this problem. Like Bob I've been running a power resistor in conjunction with the new rectifiers, but the heat it generates is objectionable.

Bob,
Out of curiosity, what is the voltage on the heaters? If it's signifigantly over 6.3vac nominal, you might want to try dropping the line voltage itself with a bucking xfmr. Just a thought.

I think I might try finding some NOS selenium stacks for my CTC-4 Director, that's the easiest way to fix this problem. Like Bob I've been running a power resistor in conjunction with the new rectifiers, but the heat it generates is objectionable.
If the replacement seleniums are gonna drop the same voltage (and hence wattage) as the power resistor, they would be dumping the same amount of heat, would they not? That's why i thought maybe the problem could be overly high line voltage (verifiable by measuring the heater voltage). IIRC, Phil Nelson had a similar issue with one of his vintage restorations.

I agree with old_coot. You'll still have the heat problem.

I purchased a bunch of NOS seleniums. I didn't have much luck with them. They were o.k. for low power applications, but when trying to run them near their ratings they would heat up and start dropping too much.

There is a conditioning process similar to reforming electrolytics for them, but I haven't tried it.

This company still makes them, CEHCO (http://www.cehco.com/?page_id=575), but it might be expensive.

I think I might try finding some NOS selenium stacks for my CTC-4 Director, that's the easiest way to fix this problem. Like Bob I've been running a power resistor in conjunction with the new rectifiers, but the heat it generates is objectionable.

If the replacement seleniums are gonna drop the same voltage (and hence wattage) as the power resistor, they would be dumping the same amount of heat, would they not?

But they dissipate the heat over a larger surface area, and there's no bracket to hold an extra large resistor. Plus, it appears stock. For example, I mounted my resistor on a bracket that interfers with the opening of the HV cage cover. With stock seleniums, I wouldn't have that problem.

Bob, Thanks for the info about the dropping resistors :yes:. I'll be pulling the chassis soon for some other work, and will build a temporary setup to check out both approaches, 350 volts, and 380 volts. My particular chassis seems to do better with the higher voltage, as applied by a variac, but I don't want to run the entire set like that, and chance a problem. I'll post results as I realize them. Glad you're feeling better!
Kevin

But they dissipate the heat over a larger surface area, and there's no bracket to hold an extra large resistor. Plus, it appears stock. For example, I mounted my resistor on a bracket that interfers with the opening of the HV cage cover. With stock seleniums, I wouldn't have that problem.

The doubler lytics and seleniums are original in my CTC-4, and run cool with proper B+ at a slightly reduced line voltage from what leaves the outlet,s so I'm going to leave them be for now.

Just out of curiosity does anyone have any insite as to why RCA used selenium stacks in the CT100 thru CTC4 series instead of 5U4s? :headscrat

Starting with the CTC5 and going forward, RCA switched to using 5U4s.

Data sheet for 5U4 indicates it will produce 225ma of dc current. I don't know what the ratings of the selenium stacks are, but my measurements indicate that a pair of 5U5s in parallel would be enough to supply the 440ma I measured in my CTC4. And further, the B+ fuse in the set is 450ma.

Here is a link to the technical data for an RCA 5U4. I must confess I'm not much good at interpriting these graphs.

http://www.mif.pg.gda.pl/homepages/frank/sheets/049/5/5U4GB.pdf

Do you think this was an issue of reliability/pushing 5U4s to their upper limit, or cost in manufacturing considerations?:scratch2:

I think that would be difficult to answer unless someone was involved back then.

I'd guess that seleniums were still viewed as reliable. You wouldn't have to deal with the 3 amps needed by the 5U4 heaters, seleniums take up less space and run cooler.

I think the space issue was why the Sylvania 1-128 used selenium rectifiers in addition to a 5U4 and 7X6.

John

Just out of curiosity does anyone have any insite as to why RCA used selenium stacks in the CT100 thru CTC4 series instead of 5U4s? :headscrat

Starting with the CTC5 and going forward, RCA switched to using 5U4s.

Data sheet for 5U4 indicates it will produce 225ma of dc current. I don't know what the ratings of the selenium stacks are, but my measurements indicate that a pair of 5U5s in parallel would be enough to supply the 440ma I measured in my CTC4. And further, the B+ fuse in the set is 450ma.

Here is a link to the technical data for an RCA 5U4. I must confess I'm not much good at interpriting these graphs.

http://www.mif.pg.gda.pl/homepages/frank/sheets/049/5/5U4GB.pdf

Do you think this was an issue of reliability/pushing 5U4s to their upper limit, or cost in manufacturing considerations?:scratch2:

OH yes! Good point John. I forgot about the need for the seperate 5v filiment winding on the transformer. Now it makes more sense. I think this was more likely a matter of ecconomics than anything else. The transformers on the CT100 thru CTC4 series were already extremely large without adding an additional 5V winding for the 5U4's.

I would also say power consumption/heat generation was the reason. By the time the CTC-5 was developed, the tube count and power consumption were reduced enough. I bet the selenium rectifiers were more expensive than 5U4s at the time.

Actually, they went back and forth till silllycon was proven reliable. CT-100, 21-CT-55 and CTC-4 used selenium. CTC-5 had 5U4's, early production CTC-7's had 5U4's and later switched to silicon, and everything from CTC-9 onwards used silicon as well. I suspect that the development of cheap silicon rectifiers was a driving force in the engineers decision making process.