My Sylvania CK3000 test jig (which also works with the RCA jig adapter cables) was only made to work with CTC-7 and later chassis, but I made a (yoke) adapter cable that works with the CTC-5, CTC-4, and CTC-2/CT-100. If I remember right, I also checked the schematics and it should work with a CTC-2B/21-CT-55 as well. There is one wire that gets either connected or disconnected among those different chassis.

The way the jig works on later chassis is, you plug in a "convergence load" to the chassis, that replaces the now-disconnected convergence control panel. However, on the CTC-5 and older models, only the convergence yoke is disconnected with the cable is unplugged from the chassis; the controls themselves are still attached, so no replacement "load" is needed when using the jig. (So, in this case, the CTC-3 chassis would still need to be connected to the CTC-2B chassis, but not the convergence yoke itself.)

If you do get that jig and you want the adapter information I have, let me know and I can probably copy it and post it here.

That looks like a low voltage power supply problem.

Where can I find a set of extender cables?
 

Gregb: where did you ever come across the set of extender cables? Are they available in Canada, since I can't seem to find them on the web. Can one buy them, or find them on e-bay? I understand I can't set up the adjustments until it's back in the cabinet, but it would make for good rough testing as I recap and do repairs to the set. It would make it much easier for me (since I have back problems), instead of getting down on the floor to work on the set, as that is really hard for me. I'll first will tackle the power supply, electrolytic's, etc. The small raster (if you can call it that), indicates definitely that it needs new caps in the power supply and will also be replacing the selenium rectifiers with diodes. I don't intend to run it much more (probably not at all), until at least the power supply is taken care of.

I have a couple extra female sockets off a test jig that you're welcome to have if you can adapt them. They have different plug ends on them, but if you had the cap off a 21" color tube you could use them and make one easily.

The sockets would help me out!
 

I'll send you info in your VK mail box.

Is there any way to stand (or brace up) the chassis on its side behind the cabinet and connect up using the original cables?

http://antiqueradio.org/art/RCACTC-4LameSetup.jpg

I realize your chassis isn't designed to stand up that way, but if the connectors would reach, that might be a way to access the underside while it's powered up.

Just an idea . . . .

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

Good suggestion Phil, and I even have a cooler just like that to sit it on. It just might work out for me. Maybe I could like tie a string, or something to brace the chassis to it stands up like yours, seems as it if would work. Thanks for the picture.

During part of my CT-100 project, I stood the chassis sideways on a square of heavy plywood. I screwed one end of a diagonal brace (a wooden stick) to the plywood and lashed its top end to the upper part of the chassis. That allowed me to make measurements & adjustments with the underside of the chassis exposed.

Tube extenders let you make many voltage measurements from above, when the chassis is in the cabinet, but if I recall correctly, there were some tubes under the CRT without enough vertical room to take an extender.

I use a second cooler with a folded quilt to make a seat behind the chassis.

Phil Nelson

It makes more sense to remove the yoke and put the chassis on the bench. You can then work your way through it, using a scope, to make sure everything is working. Then put the yoke and chassis back for final test.

Both of you Phil and Steve have very good ideas. I sort of like to see whats on the screen as I work on it, but I also understand that it is much easier on the bench. I am concerned about the yoke only in the sense that the cover is crumbling, and I believe there was a post about how to make one using something common, such as a plastic lid, or something. Of course the crumbling yoke covers were common on all of the old sets, even B&Ws as well.

I used a Home Depot paint can cover suggested by another VKer. Look at this thread post #27 to see a before and after picture of the yoke:
http://videokarma.org/showthread.php...=21ct55&page=2

The cover fit on the yoke nicely. I made three small holes to allow the rivets on the shield that mounts on the back of the cover to snap into the cover.

I did my initial powered testing on the bench with the yoke plugged in but no CRT connected. I made many quick powered checks with the HV loaded by a 40KV HV probe. Once all the voltages, currents, and waveforms looked right I put the chassis back into the cabinet laying it on its side to get at the bottom of the set.
Dave

That's a nightmare! No matter how carefully you mark a CT-100,
you will never ever get the yoke tilt the same, so you will have to
start convergence from scratch. Perfect convergence is possible
but the yoke position is critical to the millimeter, including the tilts.

I don't know if this applies to 21axp22 sets. I know I never got my
college roommate's CTC5 or 9 anywhere near as good convergence,
but they of course don't have tilts.

Two other ways to work on the chassis:

Everything on the chassis except the AGC, sweep, and HV will work without the yoke. You need to put a jumper in the yoke socket to connect the B+, though. You will need a bias box to set the AGC voltage. That will allow you to get almost all the circuits working before putting it back in the cabinet.

Make a yoke extension cable and leave the yoke in the cabinet.

What is the RCA in one of your pictures that is to the right of your find? Looks like a '58 or '59 model??

Or do what I did and break apart any octal tube to harvest the socket, and use that as your B+ jumper. All you need to do is connect the appropriate pins, and you'll have power to all the circuits. Just make sure you NEED power to all the circuits! It works on all the early CTC chassis.

The other RCA roundie in the picture is my CTC9 1959 Model
 

The other roundie is a CTC9, model 210CK924. It looks pretty good, but still needs some work. Set has low hours and has the original 21CYP22 CRT. Right now (as of yet) it is running with the original filter cans, which I still intend to replace with modern caps, although they do run fairly cool. It still has a problem with the vertical and horizontal sync at times, and the vertical height has a tendency to collapse. (I believe there is a broken ground somewhere on the vertical/horiz circuit board) Cabinet is in perfect shape, no scratches, back and everything is complete and the set when I got it was super clean inside for it's age. I obtained this on Craigslist from Blair NE. I have another post on here somewhere about the set.

Progress on the CTC2B, 21CT55, 21 inch roundie color from 1954
 

Some progress on this set, the CTC2B, 21CT55, from 1954. I removed the chassis, yoke, and convergence assembly. The set looks to be in really good shape, and it looks to be a low hours set. Yes, there is some rust on the tube shields, but other than that, it's clean, even the flyback looks really good, just a small amount of wax drippings. Here are some pictures of the chassis before recapping, and cleaning. Even the resistors don't seem to be discolored with heat and age. Next for me is the tedious task of recapping, checking tubes, cleaning, and replacing several peaking coils that are open.

Just to let you guys know why there hasn't been any more progress of restoring this 21CT55, CTC2 1954 color. I hurt my back moving a heavy piece of equipment about a month and a half ago, and I've been sort of laid up as far as getting things done. I herniated (sliped disc) in my back and it causes me a lot of back pain, and also burning pain down my legs. I have been taking pain pills and steroids for it, and also got shots of cortisone into my spine, which have helped, and also doing certain exercises to get my back into shape again. The spine doctor seems to think everything can get me back to near normal without doing risky surgery. Also have been seeing a Chiropractor. I do have the chassis removed and cleaned up, tested the tubes, (4 bad), and ohmed out the convergence transformer which has continuity on all of the windings, which is a good thing. It seems as if nearly all the white coated peaking coils are open so have to find the values and order them. Next is ordering the necessary caps, and other parts, as I am getting back into action. I sure hope I can get a good picture on this set when everything gets done. I believe it will be an on going (probably a 2 year) project.

I herniated disc in 2007 after a marathon auto repair procedure. I went to a Physical Therapist and followed her recommendations religiously. I didn't have to have surgery. I still don't lift heavy loads, but otherwise I'm back to normal.

Best of luck with your recuperation. and restoration.

In the pictures in Post #57, I noticed the name Glaser Steers Corporation on the convergence coil assembly. I remember Glaser Steers as the name of a high end record changer company. Most notable was the fact this record changer stopped the turntable when the next record was dropped. Quite a sight to watch in operation.

I am seeking some answers about replacing the selenium rectifiers with silicon diodes. I plan to leave the old ones in place for the nostalgic effect, but I do have a question for you guys. Since the selenium's drop voltage (maybe 10 to 25 volts), has anyone had any experience of what value and wattage resistor(s) to put into series with the diodes to limit excessive voltage to the power supply and the rest of the set. I obviously plan to replace all of the electrolytic's in the set (most with higher voltage ratings), but I still don't want to "cook" the set with too much B+ voltage. I have searched the web and this site and found all kinds of different answers, including putting in no resistors at all. The set is my "new" 21CT55, CTC2B, 1954 color. Of course the answer may just be taking a variac and substituting different values until the find the correct voltage (400 volts) at 120 volt line voltage as published in the Sams schematic. The line voltage at my house usually runs around 125 volts just for your information.

If I were in your shoes (I am actually, fellow 21CT55 owner), I'd always run my sets on a variac and monitor input AC voltage to make sure it's receiving the rated 117 VAC stated in the schematic. Higher voltages tend to cook irreplaceable parts, and I don't fancy trying to locate a flyback for any of my sets. I'm a big stickler on horizontal/HV circuit adjustments too, and it's served me well in collecting TV's.

I tried to find a resistor/diode substitution that worked well on my CTC-4, and in the end wound up with one of those adjustable high wattage resistors so I could home in on the perfect value without spending too much cash. Something in the 100-ohm range that is adjustable usually works, that way you can slide it around from 0-100 to see what the set likes. Just remember: if you do this while running the AC input at 117 VAC, you must always use a variac or B+ will still be too high if you forget. Most simply plug the set directly into the wall, then set the series resistance to whatever it needs to be for proper B+ readings. The tube filaments won't care about a couple extra AC volts on the line, but the effect is dramatic when looking at horizontal output cathode currect. A few input volts ends up spiking it higher than you'd expect, so monitor things and zero in on the best set of variables for it.

I ended up with a 40 Watt 4 Ohm resistor in series with the 4.5 Amp fuse to get my voltage down. I used two 20W 8 ohm resistors in parallel. You will probably need to experiment to find the right value.

Dave

Sometimes it's handy to use the 6.3VAC heater rail as a proxy.
If it's over the nominal 6.3V, a little droppage on the primary side is in order to get it back down.
And then get the appropriate droppers on the replacement B+ silicons.

It seems as if a 100 ohm adjustable resistor would be kind of high in value. I agree that an adjustable resistor is the way to go, that way I can get the exact B+ voltage by setting the resistor so that I get the required 400 volt by adjusting it. I am thinking more in the 10-25 ohm range with adjusting it to the close end would be 0 ohms and maybe like 10-25 ohms at the far end. If Zenith 6S621 achieved the proper voltage using just 4 ohms, a 100 ohms resistor would be adjusted all the way to the end. I found out that I can re-stuff at least the main filter cans, so I'm going to give it a try.

I think you are splitting hairs. These sets were designed to operate over a wide range of line voltages, and differences in components in individual sets will result in quite a variation in DC voltages.

I wouldn't worry about getting the DC just right. Even if you got the 380 v line right, the others won't match what you read on the schematic. Put a small resistor in series with the diodes and you will be fine. In fact, I don't think you'd have a problem with not using a resistor. You might end up with 20 or so volts more on the DC, which won't be a problem.

I think your right Steve, I know most all older electronics ran a tolerance of at least 10% or more. Sometimes I don't know why I'm such a perfectionist. I'll probably slap a 4 ohm resistor in series with the B+ and check the voltage. If it's within 10 volts or so, I'll call it good. Also I found a bunch of peaking coils open. Those little round white ones, mostly in the video circuits. Thanks to the internet, I'm sure I can find most of the correct (or close) values online. One of them is located in the center of the attached picture.

In my experience all the white, powdery inductors should be replaced. The yellow ones seem to hold up well. I got mine for a recent CT-100 restoration from Newark, like these:

http://www.newark.com/bourns-jw-mill...d=800000016501

But let's not forget: his line voltages are in the 125 range, and when you combine that with the 20 or more extra volts the silicon is likely to add it can get too high fast. I personally don't like risking unobtainium like CTC-2B flybacks, so I do what I can to keep things in check.

Only way to know if you're safe is checking horizontal output tube cathode current, if it's too high you risk a meltdown. Check the Sams on the set, it should have the values you need.

As to replacing the selenium, some guidance, first from International Rectifier, as found on the back of their 1965 "Universal Silicon Replacement Rectifier" rated 600V at 1 Ampere.

The second photo is guidance from Sarkes Tarzian, a maker of both Selenium Rectifiers and later, Silicon replacements. This was an enclosure with their M150 "Silicon TV Replacement Rectifier" from the late 60s. It is only rated at 360V, 150mA, obviously aimed at Black and White sets, but it too recommends adding a dropping resistor.

Others here have some great advice as well.

Indeed! And remember, wattage (and heat) don't increase linearly with voltage, but by the square of volts times amps.
That's why the earlier suggestion of using the 6.3 VAC heater supply as 'standard marker' when line voltage supply is over spec.

I think it makes sense to install a small resistor in series with the diodes, but beyond that I think no other precautions are needed. I install fuses in the cathode of the horizontal output tube on restorations I've done to protect against excessive current. Horizontal output tube current can be controlled by the horizontal drive control.

I will definitely be checking the horizontal output current as I adjust and experiment with different resistors in the rectifier/power supply circuit. Also will be following the Sams as far as adjusting and getting the 6CB5 horizontal output current as low possible keeping the width and HV within acceptable limits. Thanks for all the advice, I'm first going to start with an 8 ohm dropping resistor and bringing it up on a variac and make adjustments as necessary. I sure don't need to "cook" the flyback. Things can't go wrong, I've got my cat, Lala, as my helper. (just a bit of humor).

I think you mean
P= I * E
or P= (I squared) * R
or P = (E squared) / R

Pie R round Cornbread R square.

Update on my CTC2B, 21CT55, 1954 Color
 

Well, here is the latest. I replaced the electrolytic caps in the power supply, however haven't yet replaced all of the electrolytic caps that are in the sets circuitry. I have the chassis on the bench, so hooked up the deflection yoke, convergence assembly, and of course the speaker, without the CRT connected, and of course with the horizontal output tube pulled. Applied power with my variac, (actually a switchable isolation transformer "pictured"). At about 50 volts AC I got about 200 volts (of the rated 400 volts) from the power supply, which I suspected. Then raised it to 75 volts AC, and got 300 volts out of the power supply, so gradually raised it to 100 volts AC, and got the rated 400 volts, so left it there for a bit. All tubes lit up, so I hooked up my converter box to the antenna terminals, and got audio. It became promising, so installed the 6BQ4 horizontal output tube. I began to get 20KV high voltage, but heard some arcing, smelled ozone and something getting hot. Then the 1/2 amp fuse in the horizontal output B+ popped, before I could disconnect the set. At least it wasn't the flyback, but I found a bad focus control, arcing internally running too hot to touch. Disconnected the lead providing the focus voltage to the pot, powered it up again, and WOOO!, almost 30 KV, and pop (just a loud arc) so pulled the power cord immediately. Looked at the schematic and I noticed that the regulator 6BD4/6BK4 derives it's bias off of the down side of the focus control, so that explains the excessive HV. Also before hand, I had replaced all of the peaking coils that were bad, (those tan round balls), which nearly all of them were open. (A common problem I have run into with several other sets). Oh yea, by the way, the selenium rectifiers have been replaced with silicon diodes. Also I intend to cover the small new power supply capacitors with cardboard insulator covers to make them look like the originals for appearance sake. Another thing I noticed was that the 6AN8 tube V11 (AGC and Sync Seperator started to glow bright blue, hopefully just a bad tube). So my next move is to find a suitable replacement for the 5 meg ohm focus control. Control is quite large but is only rated, according to the Sams at 1/2 watt, 5 meg ohm. RCA part number 79028. I know workman used to make some of these style controls and focus resistors, so hope I can find something that will work.

Oh yea, speaking of PI, well PIE, the kind you eat (from the post above), the best pies you can buy in the Omaha and Midwest area are frozen ones that are home made from the Village Pie Maker. They can be found in the HY-Vee stores, Bag and Save, and other locations. They are made in Nebraska, from a small company that several local women got together and decided to make a business of it. They use fresh fruit, (not frozen), and have Rhubarb, Cherry, Apple, Mix Berry, Peach and others. Look them up, just type in a search for the Village Pie Maker. Maybe they are even available in your area.

If you can't find a 5 meg pot of the original style, another option is to use a standard 2 meg one. The voltage differential across it will be small enough to prevent arcing. You will have to experiment with resistors on either side of it to total 5 megs and have good focus at the midpoint of the pot.

I am also going to have to find something to make and use for a yoke cover as the old one was crumbled beyond use. The yoke is slightly over 6 1/2 inches round and also I am wondering if a cover from another roundie yoke cover would fit. I know someone on here manufactured his own, and also heard of someone using a plastic paint can lid. Suggestions?

Plastic top from some sort of food pail, for example, ice cream. May cost money,
but at least you can eat it.

For my CT-100 I just cut two pieces of cardboard into two overlapping
halfs, slipped them on the already assembled CRT neck, and taped them
together. You could do that with plastic sheet.

coffee can top is what some have done.