Wow, Tom congratulations! I'm amazed at how fast you got it up and running-- truly inspirational.

-Clark

Thanks!
The main reason I could do this so fast is that I had most of the right values of paper caps on hand, and enough extra wrong values to make accurate enough (I fudged some values in the audio stages because those stages are not critical, and I rarely use the sound on my sets) replacements for values I was missing. I also was on Christmas break, and until today I was able to dedicate the better part of a few days on end to working on it.

My plan of attack will be to get De Oxit tonight to clean contacts, and this week end swap the CTC4 cabinet in the garage for a roundy in my bed room/work shop/display area/big mess. Then once I have the CRT mounted in the cabinet I will concearn my self with the deflection tweaks, and then color issues.

I'll have some questions soon. Gota run!

You've made excellent progress with this one, must have given you goosebumps when finally a picture appeared on the screen :yes: Great stuff, you'll have nice set when its all done! Cheers.

Thanks!
I was barely able to get any video at first and almost did not notice that I even had any. Once I got it to synch I was briefly very excited, but it was so weak that it was difficult to tell what I was at on low contrast images. This and the unstable synch (the signal was so weak that I could barely even get a picture of the synch bar when the vertical rolled) quickly made my inner technician take over and start trying to improve the signal using any tricks at my disposal. Once I succeeded at getting the video back to a reasonable level I went right back to excitedly celebrating this significant mile stone, and proceeded to watch, for an hour, a level of picture quality that I would not bother to watch on any other set I own. I will admit that I enjoyed watching it more than any of my other, presently much better preforming, restorations. :)

Now that I have time to type more I have three questions for those whom have used these sets with the newer roundy tubes.

First is it a good idea to keep using the field neutralizing magnets on the front of the CRT with a 21FJP?

Second those knurled metal things on the outside ends of the convergence yoke that point towards the back of the set, are they the static convergence adjusters?

Third is how do I preform safety glass removal on a CTC4?

This set is nearly a decade older than any color set that I've worked on before so it is a real learning experience of how they designed them in the early days, and a good chance to sharpen my trouble shooting skills and put those skills to the test.

I tried to use them with a glass tube, but they are too weak to fix impurities in the center of the screen. I also gave you that plastic ring with the hairpin magnets on it right? CTC-9 chassis use the same thing, I'd strap that to the back of the tube and see if you can get good purity between that and the edge purity magnets from the CTC-4. The hairpins come in pairs and I think one is missing. You'll want to remove that one...


More like beam positioning, but call it what you will. Basically you center all the dynamic convergence controls, then use the knurled knobs on the conv yoke to set up a roughly converged center cross pattern. From there, you follow the Sams dynamic proceedure RELIGIOUSLY till it starts to look better. Then you do it 5 more times till it looks right. :D

Oh, don't forget to do red purity before any of that other stuff. Purity first, then convergence. ETF has the CTC-4 Sams posted if you don't already have one.

Actually, the 4 was one of the easier sets I've worked on. Most things remained about the same after the CTC-4 and 5, which were each special in their own ways. The 4 detected color on different axes than any other set before or after: R-Y and G-Y vice the typical R-Y and B-Y that came later, or I/Q that came before, along with having high level demod. The 5 had a funky demodulator circuit using 12AT7's. The CTC-7 and everything thereafter looks the same on paper, subtle changes only. Most of it is different tube types, but later ones also shed an IF stage or 2 due to getting tubes with higher gain.

That was an excellent Buggs Bunny cartoon! :)

Actually, the 4 was one of the easier sets I've worked on. Most things remained about the same after the CTC-4 and 5, which were each special in their own ways. The 4 detected color on different axes than any other set before or after: R-Y and G-Y vice the typical R-Y and B-Y that came later, or I/Q that came before, along with having high level demod. The 5 had a funky demodulator circuit using 12AT7's. The CTC-7 and everything thereafter looks the same on paper, subtle changes only. Most of it is different tube types, but later ones also shed an IF stage or 2 due to getting tubes with higher gain.[/QUOTE]
Nick.... The CTC5 had two different chassis that year. The better model had a color circuit that was simular to the later chassis.

The "super"=cheaper, the "deluxe"=better. I have a "super"

Yes, you're referring to the differences in the 'Super' and 'Deluxe' chassis. I do admit to liking the circuit with 12AT7's though, pretty nifty. :thmbsp:

Agreed!

Nick, what does "high level demodulator" mean?

As of Wednesday I got the cabinet up stairs and dismantled the CRT mask/safety glass/trim assembly for cleaning.
On Thursday I cleaned the disintegrated rubber gasket from the Glass and mask. I used Goof Off to get the rubber off the glass, and started to use it on the mask. I then realized that it would be too harsh on the paint of the mask, and switched to rubbing alcohol, which is also not particularly good for the paint, but less harsh and yet still efficient at dissolving the rubber goo.
http://i1095.photobucket.com/albums/...h/DSCN1534.jpg
http://i1095.photobucket.com/albums/...h/DSCN1536.jpg
http://i1095.photobucket.com/albums/...h/DSCN1543.jpg

On Friday I started to polish the the the brass trim. It was not going fast at all on the lightly tarnished piece I started on. After that piece was good on Saturday, I grabbed the worst corroded piece I had and started experimenting with technique, and found that vigorously scrubbing the polish on with a tooth brush was VERY effective. Sadly even though it looks good from a distance it is clear up close that these pieces are brass plated copper, and that all pieces have spots of varying size where the plating was corroded through over the years.
http://i1095.photobucket.com/albums/...h/DSCN1540.jpg
http://i1095.photobucket.com/albums/...h/DSCN1546.jpg
http://i1095.photobucket.com/albums/...h/DSCN1547.jpghttp://i1095.photobucket.com/albums/...h/DSCN1549.jpg


Nick I found out why those corner pieces were loose....Their retainer clips are busted. On the left is a good one the two others are the bad ones.http://i1095.photobucket.com/albums/...h/DSCN1552.jpg

I mounted the corner pieces with the bad retainers at the top, and reinstalled everything in this picture.http://i1095.photobucket.com/albums/...h/DSCN1561.jpg

I did a quick green purity (at the time the red would not work) and neglected to take a picture. I was confounded by the red not working for some time, but then found that there was a lead touching the screen wire terminal that was shorting the screen to ground:yikes: It looked much better after that.

The color circuits work, and I did some minor convergence tweaks to improve the picture. I still need to spray deoxit into some of the convergence pots as they can get squirly and mess with the deflection circuits. Still tons of adjustments to do which I'm going to need to fabricate a yoke extension cable to preform, and then hope that either the convergence will reach where I need it or that the set will not mind having the convergence yoke unplugged.

http://i1095.photobucket.com/albums/...h/DSCN1556.jpg
And what Nick has been wanting to see.....Color bars.
http://i1095.photobucket.com/albums/...h/DSCN1558.jpg
My camera made the left side look worse than it is, but it is clear that the demods need adjusting.

There is a nasty imtermitant that kills the signal at the second IF tube. I'm begining to wonder if the socket is bad.....

I actually lifted that set (minus the top lid) on to the black roundy my self. If it was not for the sore mussels I'd have been pretty proud of doing that.:nono::D

Hi level demods go directly to CRT grids with no further amplifiers.

Correct. If you look at most other schematics, you'll notice that each color has an output tube. On the 4, the demods go directly to the CRT without passing go or collecting $200. Thus it's high level, where the circuits requiring amplification are considered low level.

Tom,

The trim is SOLID brass. It is not plated copper. Brass is acutally COPPER, that is alloyed with zinc. The copper pits or spots you see in the brass finish are areas where the zinc has likely been depleatd from years of chemical corrosion. When that happens the base metal COPPER is what is left and it looks like it was brass plated copper. I can asure you that the trim is solid brass and you can steel wool and scotch brite until you are blue in the face and you will never wear through the plating because it is not plated, it is solid brass. For an easy way to polish solid brass trim follow this link to my web site.

http://antiquetvguy.com/Web%20Pages/...finishing.html

Good Luck,
Bob

That is pretty cool Bob! I'll have to try that sometime.


I'm trying to preform the horizontal adjustments and have hit two walls the worst of which is that the linearity coil slug is BADLY frozen (I sprayed some deoxit gold in there and nothing) I'm afraid to proceed because I may end up breaking it. Please help!

Secondly in the HV adjustment procedure it says to adjust the HV control for 25KV, and the most I can get before bottoming out the control is 20KV. Is this something that will shake out if I iterate the procedure a few times?

Putting a meter in place of the HV fuse I'm getting around (ie a little over) 175mA of current.

Sounds like the output tube isn't being driven hard enough, have you checked the oscillator for correct performance? My CTC-4 will make 25kv no problem, same with the 21-CT-55. They have very stout HV supplies, so if you can't get more than 20 I'd look for issues in the drive or make sure it's not being dragged down somehow. Check that the output has the correct negative grid bias, and make sure the waveform going into it is of the correct amplitude and shape. If that's not it, juggle HV rectifiers till it comes up. I went through 3 of them before mine was stiff enough, just because they are new doesn't mean a whole lot. I've found that color sets in particular are very picky about what rectifier they have in them.

Before the first power up I adjusted for the EXACT HOT grid drive voltage called for in sams as a safety precaution. The wave form looked decent, but I did not compare it to the sams at that time.

I just preformed the synchro-guide horizontal adjustment for equal peaks so the drive may have fluctuated, but I seem to recall that the HV was hovering at around 20KV before that so it may not have affected the drive level.

The sam's High Voltage Adjustment procedure is to,with contrast and brightness down, adjust the HV pot for 25KV connect a 0-500mA meeter (I only have a 0-250 unit on hand) across the HV fuse terminals, and adjust the linearity slug for minimum current. Then reset the cont. and bright controls for a raster, and adjust the drive pot until drive bars appear then back off until they are gone.

I was planning to iterate the process until things improved, but I'm hung up at the linearity adjustment because the lin. coil is stuck almost like gremlins have been dumping excess super glue that they have been using elsewhere into the lin coil.

Anyone know how to unstick linearity coil slugs? Even if I skip linearity and go to drive the linearity adjustment will be done in the next step or two and hang me up again then.

Try a new rectifier before you do anything else, then you can hit the lin coil with a hairdryer set to maximum warp to unfreeze it.

Well this sucks!! The damn flat head screw head on the copper adjuster rod for the linearity coil snapped off, but I finally got it loose using a combination of Goof Off poured in the track for the ferrite core and heating the coil by connecting it to 2 flashlight cells thus heating it.

I think I need a new core/copper adjuster rod assembly. Here is what it looks like..
http://i1095.photobucket.com/albums/...h/DSCN1563.jpg

I'll try to see tomorrow if my RCA 9-T-246 has a similar core in one of it's coils that I can scrounge as a replacement for the original core with the destroyed adjuster threading.

Been a lousy day between the rotten stomach bug that ruined my sleep Sunday night as well as making my folks tell me to skip school on Monday, and damaging this part. Ugh.

Edit: all this happened before your post Nick.

Same thing happened to my CT55, I just turn it with needle nose pliers. It should be possible to file a new slot into it, just be careful. Also, I always wanted to try brazing a knurled knob onto one of those.

Thanks for the advise Nick!

My file is a tad large, but if I can get the slug to rotate freely enough I ought to be able to get a screw driver to work with it after filing. I can't comment on the 21-CT-55 layout, but it would be kinda awkward to adjust the linearity control on the CTC-4 with pliers considering they wedged it between the damper and the HV cage. Not what I'd call a particularly good good place for it, but at least it is not as buried as the same adjustment in the CTC-16 (I tend to wear rubber gloves when doing live chassis horizontal adjustments on my 16's as the controls tend to be cramped, and uncomfortably close to dangerous voltages and searingly hot output tubes :thumbsdn:).

I'll try some other HV rect. tubes, but doubt they will fare better than what is in there. The tube in there is perhaps the first 3v filament HV rectifier that I've seen that will peg the needle on my tube tester, although I've heard the mantra that the best tester of TV sweep tubes is a TV set.

What the tester says means squat when it comes to HV rectifiers, unless an open or short is indicated. They simply don't test at a high enough voltage to get reliable results.

That is so true. I struggled with my 9 with strange HV issues. I could hardly adjust the HV up or down. the regulator and rectifier tested good. I replaced both with NOS and now works great. Tube testers cant always find problems with HV tubes like miniman said.

Been back on it for a bit, and here is what has been happening.

After my last post I scrounged a replacement slug from the width coil of my 9-T-246 that seems to be the best thing I have on hand. pictures below.
http://i1095.photobucket.com/albums/...h/DSCN1571.jpg

http://i1095.photobucket.com/albums/...h/DSCN1575.jpg
The HV was (and is still) at 20 KV. The dead IF intermitant that was bugging me devolved into a completely dead IF.
I then got too busy to touch the thing for several weeks.

I got back to it over the week end.

The IF has gone back to intermitantly not working from being dead merely by sitting around. I'm fairly sure this set will need an alignment at some point to work right as color sound and monochrome don't seem to lineup as well as they should.

I did not feel like messing with the IF and HV issues, and instead began tweaking the color circuits. It was hard at first because I did not have a nonmetalic alignment screw driver that was long and slender enough for the dual-core transformer let alone two to tweak both slugs at once. So I went to Radio Shack to see if they had those tools available, and let me tell you that I felt like I was in a grocery store that doesn't stock bread when I was told that those tools haven't been on the shelves for a long time! I ended up making my own alignment tools from some used up mechanical pencils I had laying around from the previous quarter of college which were waiting to be thrown out (good thing I didn't get to that). Shown below are my home made alignment tools.
http://i1095.photobucket.com/albums/...h/DSCN1618.jpg

http://i1095.photobucket.com/albums/...h/DSCN1619.jpg

I have the color adjustments a good deal better than before, but there is still much room for improvement.
http://i1095.photobucket.com/albums/...h/DSCN1621.jpg

http://i1095.photobucket.com/albums/...h/DSCN1624.jpg

Think I'll go at it some more tomorrow......I should really get to bed now.

Hey Tom, this thing is really coming along. It looks good, I saw it in person before you got it. How's it going now? Have you had the time to keep working on it? Good job!:thmbsp:

A heck of a lot has transpired since my last post in this thread: College finals, a move from an apartment into a sizable house, work on the CTC-4, and I have on going remodeling(my folks are counting on my skills), emptying out of my families HUGE storage unit and work to get my stuff set up and arranged(which is tough to do considering that the other two things eat up a comparable amount of time to college).

I have not mannaged to work on the CTC-4 since the move, but before that I was working to remove the rust from the tuner shields and making decent progress(I lost some screws though :sigh: ). It was coming along nicely and almost done, but it is starting to rerust so I may just spray paint the offending surfaces silver and say 'good enough'. Part of me wants to use lacquer, but I don't have a great budget and want to save where I can.

About all the actual 'work' I've done on any of my equipment was setting up my stereo/video system (which not only is unfinished, but already needs to be mostly redone because of new finds changing the way I want to do things), fixing an Atwater Kent model 40 for (and with) a friend, and starting to spray paint a rusty TV cart that is a factory accessory for a Zenith set I like.

As the set sits the alignment is lousy, that damn IF intermittent persists, and I feel like, given the behavior of the color demods tinting the raster(or was it selective weak colors...crap I'm starting to forget things!), that there are probably off tolerance resistors that I need to look for and replace before taking Nick up on his generous offer to align it for me. Once it is aligned that may be it for the electronic end of the restoration unless I buy some fresh pots for the convergence board. I really doubt that I can preform the kind of cabinet restoration this set needs(I want to teach myself refinishing etc. later this summer if I can but don't know if I will have time), but I don't know if I will be able afford some of the repro parts I need for this set this year let alone pay for someone to restore the cabinet.

I've got a lot of projects calling for my services at present, but one of these days I'll get back on it.

Tom,


There is a guy right there in Milwaukee that can handle the cabinet for you, he did my CT-100 for me and it turned out better than new. Didn't charge too much either. Hit up Bob Galanter for his contact details, guy's name is Dennis.

I'm back on the chassis after only a brief ~8 year break.:eek: lotta water under the bridge since then. I got my EE degree and a job. When I got this Seville way back when I had around 10 monochrome TVs, 2 tube rectangular color sets, and 2 CTC15 clones....I now own every RCA color before the CTC-7 (2 each CTC4 and 5), Philcos first production color and Motorolas third (which even combined together are rarer than any RCA). And own or have serviced almost every RCA roundy from CT-100 to CTC-20 except the 7 and 10-12....

This resto originally went on hold due to a move and the sets apparent need for an alignment....in the mean time I have acquired sweep alignment equipment a good 21AXP22 to install, some cabinet restoration skills, a replacement CTC4 Havilland bottom board to replace the bowed one in my Seville and even a complete CTC4 director in better condition than this Seville....when I stopped working on the Seville chassis it had the tuner bracketing and shields disassembled for cleaning and rust removal (it all rerusted since then), a number of kludgy parallel caps and lousy ancient 70s NOS lytics from Chester electronics that were slightly leaky when acquired but better than the originals I also had forgotten to solder some of the AGC caps I changed. :o ...I also had a mishap where I stepped on the selenium rectifier and bent it to heck....
So why am I picking this basket case up? Well I was trying to get the picture to look GOOD on my CTC4 director and was leaning towards doing an alignment on it, but decided to practice on my worse Seville chassis first so if I screw up there's nothing to loose... Also I have all the extension cables stiting out to use the director as a test jig and the Seville chassis has been sitting out for almost a decade so it couldn't be easier to pick it up and start on it. So I replaced the seleniums, the percentage of lousy caps I used last time, changed the junk 2nd IF tube socket, painted the tuner brackets and IF shield an automotive gray that looks better than rust and it lived again and ran as well as it did before if not marginally better.
Before trying an alignment I went through all the resistors in the IF changing any off tolerance and that helped, then I went through the luminance channel and AGC/sync sep resistors and that really helped....color sync and demodulation was still a bit wonky though so I did the resistors there too...now it looks like I may be able to call it done soon. The 2 issues I have left are the fine tuning needing to be at max to have a good picture (I'm going to adjust the channel osc slugs) and I need to check and address the low HV issue I had years ago.
Once I get it working I'm probably going to put it in the director till I can get the director chassis as good or better. The Seville cabinet needs a lot of work and I need either a new HV cable insert for the shroud or to fix the snapped off CRT contact spring on the old one (the one in the director was broken and arcing when I got it and I swapped the Seville one into the director.
I don't want to work on the directors original chassis until I can track down 5 more good 6AZ8s and a 6AG7... The 9 pin sockets especially the IF are delicate and I only have 1 correct good spare left. If someone has those tubes and wants to sell them I'd be grateful...

Onward!

Congratulations sir!

John

Thanks.


Last night I checked the HV and it is measuring a steady 25KV.

I just need to go after the tuner, stick this in the director cabinet and converge it...the convergence yoke is the only cable I don't have the fittings to make an extension for. My solution was to leave the one in the director cabinet unplugged and grab the yoke from the Seville to act as a dummy load for the chassis. The convergence yoke plug is essentially a 6-pin version of the battery connector on a tube Zenith transoceanic...I have a 5 pin cable and socket off an old Baldwin organ, but no 6-pin connector.

When I do get the Seville cabinet done and ready for 21AXP I'm going to need to do something about the pictured cable. There used to be a contract spring (curved piece of flat spring steel) coming from the center of the bullseye that broke off and has been lost... I'm considering trying to solder a flashlight spring on and see if that works.

From the kludge department:

Friday night I got the VHF tuner dialed in had to adjust the slugs for each channel plus the hidden master slug for CH13 and a coarse osc adjust trimmer. The procedure I followed was to start at 13 making the coarse adjustments to give it enough range and work my way down the channels.
I started. By going the other way and made things worse before making them better.
All but one channel has good sound color and monochrome alignment on the fine tuning and all channels optimum fine tuning is in range of the fine tuning control...I would have liked to line up the osc so each channel is the same position on the fine tuning but that isn't easy especially with my body position effecting reception and affecting it differently on different channels...But it is good enough that it should work well on any VHF channel I'm ever going to pipe in to it and that's all that matters to me.

Last night I took a crack at making the UHF tuner work....it will tune in everything from 13-35 on one position of the UHF tuner and nothing elsewhere. Since I don't use a UHF modulator normally and only wanted to make the UHF channel indicator match the tuner position I decided to leave it alone.

I also removed the safety glass and trim and cleaned the rotten rubber gasket gunk off the bezel with isopropanol and off the glass with goof off. I then polished the bottom of the brass trim with brasso and steel wool and sprayed lacquer on it. I reassembled it upside down to hide some small dents and and minor color difference on the bottom. I may go back and hit a couple spots on the side which I notice more now that it is back together. I'll post some pics of the cleaned up trim/safety glass later.

All I need to do now is convergence and reassembly.
Once that's done I'll go back to my Moto 21CT2B and order the tubes the other CTC4 chassis needs and some slip plate to replace the silver foil that has peeled off it's CRT shroud.

That all has to wait for the folks to release me from work on the enclosure for our covid19 anti-starvation garden...

A week ago Sunday I assembled it and tried to adjust the dynamic convergence...It seems like only the blue H amplitude control behaves as it should (vertical seems to be okay).
I decided that I'm not going to sort about the dynamic convergence being poor. I ran it through the whole Wizard of OZ and at the end installed the back it was then that the only 2 original capacitors (the B+ doubler caps) decided to fail so the next morning I changed them and then gave it another OZ run through (this time with a little less pointless letter/pillar boxing from my settings challenged Blu-ray player. The next couple of days I gave it some run time too. Last time I ran it green seemed too strong in the grey scale.... I'm eventually going to check the green video tube as I changed its B+ resistor to match the red tube and sams (it matches the RCA issued schematic) to try and improve green demodulation response.

At some point hopefully soon I'm to try to spruce up the Seville cabinet....After t tubes I need for the director chassis arrive I'll try to make the director chassis work better than the Seville chassis does then I'll pull the Seville chassis out of the director and try to have both my CTC4s working....

If your convergence controls are non-responsive, you may have to rebuild your convergence board. Those 100 ohm pots are notorious for wearing out. My Hallicrafter CTC4 clone that problem and after rebuilding everything it worked perfect. AS I recall there are 6 100ohm dual concentric pots. The carbon paths wear out.

Yeah I'll probably be looking into that after this covid mess is over.

A couple of months ago I bought a fixed resistor kit that I pulled from for the Seville chassis and somehow up until yesterday I thought they were 2W parts...I double checked last night and realized they are 1W so I'm going to have to go back over the Seville and ID every 2W I changed and replace those with proper 2W parts. :stupid:

Not to threadjack, but anyone here have any ideas on what to do if the tuner's dead? My '4 is good up to the tuner now. But I can't get a darn signal from the antenna through the tuner. I *think* the issue is in the RF amp, but this thing s so stuffed with...stuff, that it's hard to nail it down. Naturally, RCA's literature isn't useful here. I tried resistance checks via Sam's, but that was inconclusive (I'll try again with someone to write the results for me.)

Any ideas? Also, what's the 'normal' agc voltage for this puppy?

Tuner problems are mostly mechanical and straightforward. Check first the tubes are lit and the prerequisite B+ is present. No signal the AGC should be close to zero volts.

Can you inject a signal to the IF input? Do you get snow? Has anyone tampered with the adjustments? Is the local oscillator working?

Post some more details as the problem should be easyy to diagnose.

My working assembled set is not on the bench presently and has stuff sitting on it blocking me from opening it for measurements.

If you haven't already done so definitely clean the contacts in the tuner.

Penthode - I'm going to do a bit more probing here, stay tuned (heh) for updates...