View Full Version : 1956 RCA CTC-5 is ALIVE!


bigaudioal
08-19-2016, 02:34 PM
Finished the recap of my CTC-5 the other day. Now I am fighting the extreme learning curve of doing a color setup for the first time. My first two shots at it took place over the last 2 days. First attempt was awful, but second attempt has yielded decent results. Have to work on the purity again, but convergence is decent. Not perfect but not too bad for never having done one before. Happy with the recap and general functioning of the set so far. Progressing photos below.

Also video here:

https://www.youtube.com/watch?v=4Mrmr4OLePU

DaveWM
08-19-2016, 02:59 PM
a tip, do the Purity setup BEFORE the convergence, they interact. Also let it warm up for at least 20 min. The deluxe chassis has that odd convergence that uses DC for the static (electromagnetic vs PM)derived from the cathode circuit of the horz out IIRC. Nice in that you can do the static with pots (if they are still good) from the front of the chassis, but seems like it would go out of static as the tube aged.

bigaudioal
08-19-2016, 03:15 PM
a tip, do the Purity setup BEFORE the convergence, they interact. Also let it warm up for at least 20 min. The deluxe chassis has that odd convergence that uses DC for the static (electromagnetic vs PM)derived from the cathode circuit of the horz out IIRC. Nice in that you can do the static with pots (if they are still good) from the front of the chassis, but seems like it would go out of static as the tube aged.

Yep, gonna redo the setup this weekend. Think I get better each time as I keep re-reading the service literature and understand what I am doing more each time.

Degauss
Purity
Convergence

Learning as I go. I was looking for the convergence cluster adjustable magnets and then realized the CTC-5 convergence is done mostly with the controls on the front. Except for the blue lateral magnet on CRT neck. Thought I was missing something when I saw a lot of other early color sets with these adjustable magnets on the convergence cluster. It's a slow, steady, learning experience that's for sure. But fun!

DavGoodlin
08-19-2016, 03:17 PM
Great work Al. That CRT looks as good a new one.

Make sure you degauss it first. I did one ages ago but did not mess with those little magnets around the CRT edge.

Electronic M
08-19-2016, 03:18 PM
It probably don't need it, but I always degauss sets that don't have an internal degausser.

If all adjustments are off to start with I tend to rough in purity and static convergence iteratively till both are perfect then after that go after the dynamic if needed.

bigaudioal
08-19-2016, 03:33 PM
Great work Al. That CRT looks as good a new one.

Make sure you degauss it first. I did one ages ago but did not mess with those little magnets around the CRT edge.

CRT is a red bell rebuild. Dated 1968. Tests BRAND NEW!

zeno
08-19-2016, 04:24 PM
Hint for convergence & purity on ALL sets.
Rough things in.
Degauss & do purity.
Turn the bright & contrast down a little & adj focus for
smallest dots.
Ignore everything but the center.
For center just picture arrows at 3 angles & the blue lat a side to side arrow.
It can all fall into place in seconds.
When doing the edges go back & forth with the center, they interact.
Always give the set a good warm up, the shadow mask can distort
over time. NEVER expect perfection !

The set looks good already, well done !

73 Zeno:smoke:

reeferman
08-19-2016, 07:38 PM
The edge magnets were made for the 21AXP22 CRT. If you have a 21" FB/FJ CRT, be sure to back the magnets all the way out, or better yet, remove them. That way they will have no affect on the purity. Just grab the knurled knob on each magnet and pull straight out. You have a nice set. I used to own one and it was very reliable, but converging it was a bear.
Have fun.
Phil

Kamakiri
08-19-2016, 07:54 PM
Great work Al. That CRT looks as good a new one.

That's the AXP I got from you :)

Sandy G
08-20-2016, 08:28 AM
Lessee what one of these "Video Display Devices"-One shudders to call 'em TELEVISIONS look like in 60 years...

Steve D.
08-20-2016, 03:13 PM
Getting some great set up tips.
Nice your CTC-5 "Arliss" has the rare factory UHF. While not of any use now, it is a bonus. Just FYI, posting the UHF instructions for the CTC-5 Deluxe models.

-Steve D.

sampson159
08-20-2016, 06:11 PM
after all these years,there is still something magical about a vintage set like this.just to see one still around but actually working is exciting.beautiful colors and real wood cabinets.this is when we made a real product that stood the test of time

MRX37
08-21-2016, 09:54 AM
this is when we made a real product that stood the test of time

You know I hear this a lot, but I see a LOT of electronics made in the 70's, 80's and 90's that are still going strong, and this is 20, 30, 40+ years later. They too are withstanding the test of time.

sampson159
08-21-2016, 09:22 PM
yes!especially zenith sets from the 70s.you can have anything after 1980

Sandy G
08-21-2016, 10:03 PM
I always thought it was the goal of consumer electronics designers to figure out how to make something last til no more than a week longer than the last payment was...

Tom9589
08-22-2016, 04:21 AM
Sandy, you are close but not 100% right. Consumer electronics is supposed to last about a week after the warranty has expired.....

dtvmcdonald
08-22-2016, 09:08 AM
Why isn't UHF of use now? Our OTA NTSC station is Ch. 39.


My agile modulator goes up well into the UHF OTA range, and
using it to broadcast in the house OTA is a lot more convenient
at UHF. For example, I can watch TV (not just HSN on 39) on my
balcony using UHF on any of my portable TVs, or out in the yard
on my battery color portables (a modern RCA NTSC/ATSC set, or the
Indextron (which will run on batteries) ). ATSC does not work
below the balcony unless I'm out at the boathouse. (Our faux
upscale apartment complex has a lake and "boathouses", really
just gazebos.)

P.S. ... the CT-100 works quite nicely at UHF.

Tom9589
08-22-2016, 10:41 AM
When analog TV went away in 2009, all of the television stations' frequencies were scrambled up. The three main stations in Atlanta: 2, 5 and 11 retained their numerical channel designation, but were all shifted into the UHF range. Oddly, our educational station, channel 8, remained at that frequency.

So the UHF frequencies are definitely being used. It's just their format has changed to digital.

Electronic M
08-22-2016, 10:43 AM
There are fewer low power NTSC channels on the air. I have not known of any in my area in the last 2 years (aside from the VHF ones I broadcast). Now that analog cable is gone in my locale I'm going to have to put a modulator or two on UHF sooner or later. I've always kept my modulators on VHF so my pre-1964 sets could all tune them.

DavGoodlin
08-22-2016, 02:52 PM
That's the AXP I got from you :)
Glad to help, as I had nothing to put it in.

That old shop had this AX left and that CYP so I grabbed both and passed them along to those who need them..

That Arliss model was the perfect candidate!

DavGoodlin
08-22-2016, 03:01 PM
When analog TV went away in 2009, all of the television stations' frequencies were scrambled up. The three main stations in Atlanta: 2, 5 and 11 retained their numerical channel designation, but were all shifted into the UHF range. Oddly, our educational station, channel 8, remained at that frequency.

So the UHF frequencies are definitely being used. It's just their format has changed to digital.

In Philadelphia, 6-ABC and 12-PBS stayed on VHF, 3 and 10 went to UHF. Two of the seven DT stations in the Harrisburg area are VHF. One stayed on 8 and the other went from 27 to 10, and is a bigger reception problem than ever now.

With NTSC being extinct in our area, I wish it was all on UHF. We STILL need bigger VHF antennas and broadband combos that are even larger: sigh: making our rooftop antennas very obvious.

bigaudioal
08-24-2016, 01:47 AM
CTC-5 was looking great until it blew the horizontal sweep output fuse tonight and I lost HV. Fuse is a .300 amp 250 volt C type. Assuming it is not a slow blow fuse, correct?

Now I am really gonna leave it be until someone more knowledgable than me can run some key diagnostics to make sure the set is running ok. Anything obvious I should look for that may have caused this?

Figures!!! Just got the convergence all set up!

bigaudioal
08-24-2016, 01:55 AM
Another pic

Electronic M
08-24-2016, 07:54 AM
CTC-5 was looking great until it blew the horizontal sweep output fuse tonight and I lost HV. Fuse is a .300 amp 250 volt C type. Assuming it is not a slow blow fuse, correct?

Now I am really gonna leave it be until someone more knowledgable than me can run some key diagnostics to make sure the set is running ok. Anything obvious I should look for that may have caused this?

Figures!!! Just got the convergence all set up!

Key with any roundy is to adjust the horizontal linearity/efficiency coil for minimum H output cathode current (it will be a dip) using a 0-250mA or 0-500mA meter in series with the cathode. Should be covered in sam's horizontal adjustment procedure.

It is also wise to look at the H osc. waveform on a scope to make sure it is correct, and check the grid drive of the H output tube before the current dip to ensure the tube is being driven properly.

bigaudioal
08-24-2016, 08:03 AM
Key with any roundy is to adjust the horizontal linearity/efficiency coil for minimum H output cathode current (it will be a dip) using a 0-250mA or 0-500mA meter in series with the cathode. Should be covered in sam's horizontal adjustment procedure.

It is also wise to look at the H osc. waveform on a scope to make sure it is correct, and check the grid drive of the H output tube before the current dip to ensure the tube is being driven properly.

Thanks. Nick Williams is going to drop by sometime soon and hopefully help me check all this. I do know where the horizontal linearity/efficiency coil is and this check looks fairly simply. Just set meter to mA's and hook between chassis ground and the exposed top of the horizontal sweep output fuse (after replacing it with new fuse). Then tweak the coil for the minimum mA reading.

zeno
08-24-2016, 08:38 AM
Leave fuse out. Amp meter completes the cathode connection.
Usually you also put a cap ( .01 IIRC ) across the meter too.

73 Zeno:smoke:
LFOD !

Electronic M
08-24-2016, 11:00 AM
Most procedures I've read call for a .47 cap, but in my experience the cap usually don't make a difference.

bigaudioal
08-25-2016, 11:08 AM
Thanks fellas!

bigaudioal
08-30-2016, 03:04 PM
CTC-5 update. Got a beefier variac and a few replacement fuses for the horizontal sweep output circuit. Powered the set back up at 115 volts and measured the current on the horizontal circuit. Was reading 230 mA. I hear it should be around 190. So need to adjust the horizontal efficiency coil. However, the coil is frozen up solid. Need to pull the chassis and try hitting the coil with a hair dryer or heat gun to free it up so I can properly adjust it.

Also need to figure out a way to secure one of the dynamic convergence control pots to the chassis. The locking tabs that did secure the pot were broken off and the pot just hangs by its wires. Makes it virtually impossible to adjust while set is playing. IIRC, it is the blue gun control (Tilt and Amp). Will work on these two issues over the next few days.

DavGoodlin
08-30-2016, 03:19 PM
6CB5's cathode current AND high voltage varies with brightness. Checking cathode current on 6BK4 (850 microamps) is part of the procedure. If you adjust the HV for 24 kV(?) and the current at 6BK4 falls below that value, the eff coil needs readjusted. Lots of interaction.I'll check my library of RCA stuff to see the exact procedure and email it.

Hopefully the eff slug was not adjusted with a metal allen key, which splits it, requiring very careful removal by hand, using a drill bit.

kvflyer
08-30-2016, 03:21 PM
Can you rob the housing from a donor pot?

bigaudioal
08-30-2016, 03:32 PM
6CB5's cathode current AND high voltage varies with brightness. Checking cathode current on 6BK4 (850 microamps) is part of the procedure. If you adjust the HV for 24 kV(?) and the current at 6BK4 falls below that value, the eff coil needs readjusted. Lots of interaction.I'll check my library of RCA stuff to see the exact procedure and email it.

Hopefully the eff slug was not adjusted with a metal allen key, which splits it, requiring very careful removal by hand, using a drill bit.

Pretty sure that normal operation of the CTC-5 chassis was more like 19-22kV with the optimal reading being 20kV. This chassis is the one everyone complains about having lower HV.

bigaudioal
08-30-2016, 03:35 PM
Can you rob the housing from a donor pot?

I checked my donor chassis and parts bins. I got nothing close so far.

miniman82
08-30-2016, 05:03 PM
Duct tape.


On the horizontal setup, follow the procedure outline in Sams/RCA literature. First thing is to make sure you dip the efficiency coil for minimum reading on the cathode of the HOT, then set 6BK4 current for .8ma with brightness at minimum, which should give you an anode voltage of 20kv or somewhere in that ballpark. But from experience, you'll probably want to set the 6BK4 a little less than that to give you some headroom on the anode. My Wingate was so weak I could disconnect the shunt tube and still struggle to get strong HV to the picture tube. Just the way it is.

If you'd rather wait, it's gonna be a month till I'm back around and BTW I won't be available Saturday till later on in the evening. So if you can't make it down here for a drop off/training session this Saturday around 6pm, we probably won't be able to get together till I get back as I have plans with the family that's going to take up the rest of my labor day time off. Let me know.

Electronic M
08-30-2016, 06:23 PM
I checked my donor chassis and parts bins. I got nothing close so far.

If the pot and chassis are not aluminum you could try soldering. I've got a 150W iron (probably meant for soldering gutters together) that can do jobs like that.

miniman82
08-31-2016, 09:05 PM
Doubtful, I have a 230w Weller hat struggles with heavy gauge chassis metal.

Electronic M
08-31-2016, 11:34 PM
Doubtful, I have a 230w Weller hat struggles with heavy gauge chassis metal.

If it is a gun it probably will not work as well as an iron of the same or close wattage. Irons should be fairly close to 100% efficiency (being resistance based), whereas those transformer based guns will loose energy in the field and connections to the tip, and also lack thermal mass in the tip. I've gotten good joints on some pretty beefy steel with mine, and I think if he tinned both surfaces individually with an iron like mine he would probably be able to make a solid joint.

Kamakiri
09-01-2016, 01:23 PM
I have access to a 7 parts chassis, if anything in there will work.

DaveWM
09-01-2016, 02:36 PM
there is more to cathode current than just the eff coil. You should try swapping tubes in the HV (rec/damper/shunt/output) and see which give you the best low reading. a gassy tube can create havoc. Also you should check the drive signal to make sure its good.

bigaudioal
09-13-2016, 04:37 PM
CTC-5 update. Well I think I got all the kinks ironed out. The beefier variac seems to be able to handle running the set indefinitely at 115V. No issues there. I adjusted the horizontal sweep coil, which is now running steady at 194 mA (instead of 230 mA).

I had a wonky horizontal for a bit and think it was due to rusty and dirty ground contacts on the horizontal board. Popped it out, cleaned them up and horizontal came back and has been rock solid ever since. I mounted the blue gun vertical amp/tilt control pots with some epoxy to the chassis. Seems to have worked well. I watched several hours of football on Saturday and Sunday without any issues. I placed a small muffin fan inside the cabinet aimed at the power transformer and two rectifier tubes. Boy, that really helps keep them WAY cooler while the set is operating.

Loving it!!! Below is a video link and some photos for your enjoyment. The photos seem to white-wash the picture a bit. Looks better in person.

I feel extremely lucky to have my first vintage color restore come out this well, especially on a CTC-5. Think the like-new, rebuilt in 1968, 21AXP22 has a lot to do with it. Supposedly it was never used after it was rebuilt.

https://www.youtube.com/watch?v=a4ZNEQDVRNM

DavGoodlin
09-13-2016, 05:02 PM
Great job Al! I like how that tuner just pulls WJLA-TV right out of the air - Its tuned to ch 7, right?:D

I have to tune my RCA's to 3 and hook up some silly box:sigh:

bigaudioal
09-13-2016, 11:09 PM
Great job Al! I like how that tuner just pulls WJLA-TV right out of the air - Its tuned to ch 7, right?:D

I have to tune my RCA's to 3 and hook up some silly box:sigh:

Ha!! I wish it was that easy Dave. I have DirecTV hooked up to my agile modulator (which broadcasts out analog channel 7). I built a dipole antenna for channel 7 frequency for the modulator to transmit with.

DavGoodlin
09-14-2016, 01:34 PM
Ha!! I wish it was that easy Dave. I have DirecTV hooked up to my agile modulator (which broadcasts out analog channel 7). I built a dipole antenna for channel 7 frequency for the modulator to transmit with.
I remember now, its in the same room ten feet away :stupid:

I have mods for channel 5 and 7, not set up yet until I find a UHF BT-AM60 or such. About half my 52-64 sets have UHF.

And that "new" Color set of yours has it too!

Stlouisian
09-18-2016, 01:07 PM
I also have a CTC-5 Arliss and was wondering the controls behind the pencil box have knobs on them besides the horizontal hold?

Steve D.
09-18-2016, 02:20 PM
I also have a CTC-5 Arliss and was wondering the controls behind the pencil box have knobs on them besides the horizontal hold?

There are no knobs located behind the CTC-5 pencil box. However, no shortage of pots many dual function some within the customer controls.

-Steve D.