Ctc17 has been gone for awhile now.

Easiest is using a socket adapter for the 6JE6/6LQ6 and a 300-500mA analog meter. I have a center zero one, so hooking up requires no polarity. The adapter is a Pomona 2599, and breaks the cathode circuit for you-available on eBay and other vendors.

Make sure you have a spare horiz efficiency coil - mine was seized, so i swapped coils before I started. 112875 is the part number.

Yes, an analog meter is imperative since digital meters are prone to going nuts on complex waveforms. We just used a Simpson 260 and a Pomona adapter for the cathode current.
Since we were an RCA dealer and the first imperative was keeping the damn sets working thru their warranty period, we put the power xfmr. primary tap for 'high' line voltage, and the H.out cathode current as low as possible, 200-205 ma. max.
210 ma. would have been the absolute upper limit for any degree of longevity.

I'm starting to think my HV probe is lying to me.

http://img.photobucket.com/albums/v4...psezoxqoyg.jpg

I swapped a couple tubes tonight with the CTC20 just to see, and I swapped in my NOS 1V2 focus rectifier and this is what I saw when I went around to the front of the set. A little tweak to the focus adjustment, the picture is razor sharp, my camera won't even catch how sharp it actually is.

This is the first time it's ever given me a color image.

It's also very bright and clear. I let let it run for 10 minutes on the dot and shut it off, and checked the fly, and it wasn't even warm.

I'm starting to think it's not the fly and more dead caps. It refuses to fill the screen vertically, and when no color is present, the image still looks yellowish. As soon as color pops, it looks good. It has full horizontal and locks on with out much fuss.

I TOLD you...you were NOT that low on HV...now I am SURE of it !! That pix looks like at LEAST 24KV to me--maybe MORE.

Was one of the tubes you changed the H-osc tube or damper? A weak osc tube WILL allow way too much current through the fly, lower HV and overheating. As others have said--you DO need to check the H-drive current level now--to make SURE it is under 220 MA. Cool fly tire and core or NOT...you NEED to KNOW.

Yes. I had one Damper crap out on me, so I've switched it. Same thing for the H-Osc tube. I swapped it as well.

I'm going to tug the chassis out tomorrow and add in the two needed wires and the cap so I can check the current. I want to make sure it's below 220 so I can baby this fly. I ran the set again for a few minutes, and it's stable and very bright.

I'm gonna get together with Electronic M soon hopefully, and I think we can hammer out the last of the sets issues and make it work fully again.

That is not far off from how it should be running.

One thing that may be worth wile when doing the current check is to add a 1/4 amp fuse to the cathode....It will lend some protection and if you (or I) mount the fuse holder above chassis it will facilitate future current checks and adjustment (just pull the fuse and connect the meter).

I like this idea. I may have you do that so it can be checked. I'm happy this set is showing it still wants to work, I was really bummed out when I first got it home and found it not really functional.

Teamwork. I like that!

Only 2-1/2 weeks to the next WARCI swap. See you guys then.

.

It may have been suffering low HV before, but no longer. The new focus rectifier, and the shuffling of tubes... And I also cleaned up some dust build up inside the HV cup on top of the flyback box since there was some arcing in there, and I also changed out the anode lead to the CRT with a 50kV rated wire from an old computer monitor, which took care of all the arcing, and makes a nice connection to the CRT, as well.

(and a minor adjustment to my meter so the needle would stop sticking)

http://img.photobucket.com/albums/v4...pshgtbhrov.jpg

25kV! Now, the Hi-Volt adjust is cranked open all the way, so that could be something else, time will tell once it gets more issues, and caps changed.

Now for everything else. One step at a time. This was a big step for me, very excited to see color, 25kV on the meter, and a bright stable image. This will be a nice set again soon!

Could be the 1.5 meg resistors around the hv pot, may have drifted.

Be careful with the HV and a bad/low output focus rectifier. Folks see low HV, crank up the HV, and then have out of focus pix, so they replace the focus rectifier tube or diode, and now they have too much HV, and too much focus current - it smokes the focus coil on these old sets (happened to my CTC16) - it's a no wonder the focus coils were QT parts.

I'm overhauling it for Arcanine. So rather than fill my PM box and keep it hidden, here is a public status update.

I started work on it today. As gotten screen shots: http://i1095.photobucket.com/albums/...psxozgoedj.jpg http://i1095.photobucket.com/albums/...pswwycoege.jpg

As can be seen the grayscale was very yellow. I also had to tweak the chroma osc. to get the color bars shot.

I could not get setup lines with the service switch and had to resort to playing with the brightness and CRT bias switch to get them.....The blue was still VERY weak with it's control maxed (had to douse the lights to balance the lines with the G2 knobs)....I'm probably going to test the gun biases later to see if something is messing with the blue.

That got me here:http://i1095.photobucket.com/albums/...psuwq2d34w.jpg http://i1095.photobucket.com/albums/...psdgyls7pd.jpg

I decided to verify HV level on my probe. With the set running on 117VAC it's producing 23.5KV, which is within the 22-24KV listed in the sam's.

I removed the chassis and decided to look at the ruined power switch. The shaft of the vol pot/power switch on the donor CTC-20 chassis was 1/2" too short, and the switch was different so that was eliminated as an option.
Opening the original switch revealed that a piece of black phenolic (SP?) that connects the switch contacts to the shaft broke. Attempt to duplicate it failed due to limited tools and lack of knowledge of the shape of the damaged part.
I then remembered I had some spare pots with similar switch shells. None of my spare pots had the right shaft length so I tried to transplant the switch section alone. One had different guts that I ruined trying to adapt to the original. The second was identical to the original switch section and I was able to mount it successfully. It works well, and no one would ever think it was a replacement. The white piece on the original shaft in the picture is what the broken black piece in the original switch should have looked like.
http://i1095.photobucket.com/albums/...psajrejtcv.jpg http://i1095.photobucket.com/albums/...psouwzyqzq.jpg

Now that the grayscale is right and the power switch works again, it is on to other work.....Like changing original caps of types I do not trust, going over the vertical circuit, and some adjustments, etc.

Looking good! What's the HOT cathode current running?

Always replace the cap attached to the cathode of the 'GF7 - that cap, more than any will cause problems with the vertical. Also go over the ground eyelets on the boards. Vertical / horizontal sync problems are generally caused by resistors way out of tolerance. I've restored three CTC16 sets, and outside of electros, the cathode cap, the sync resistors, and a thermistor or two, I've never replaced a single film cap.

Also clean the pins on the IF tubes - video will suffer If problems there.

Like I said, looking real good!!

Oh wow. Those colors are really good. You really managed to get rid of that yellow it was suffering.

Excited to see the progress. This was just one of those things, I was so let down when I got it home and it almost was completely dead, I was so disappointed I didn't find my self wanting to work on it.

I got it as far as proper HV, and color on the screen then passed it on to you.

When we tested my CRT, didn't it show all the guns were pretty good? Seems strange blue doesn't want to play nice.

IIRC it was blue that failed the color tracking test. This could be a side effect of that, or something else could be off in the gun bias circuits.

It may wake up. I have no idea how many years that TV was sleeping and how long that CRT went unused. It seems like it has a hell of a picture.

Red eye status update.

I've found why the screens were funky. The 1020V boost was 200-300V low. The 100K resistor between the rectifier and it's loads was 2.5X rated value. Replacing it got it half way back to spec. Replacing the boost diode with 2 1.5KV PIV rated silicon ones (1 probably would have been enough, but there is no kill like overkill :D ) in series brought it within 35V of spec.....I'll call that close enough of a tolerance for my taste. Now I can back the CRT bias switch off a click and still get a bright blue set up line. :thmbsp:
http://i1095.photobucket.com/albums/...psai0hshj9.jpg http://i1095.photobucket.com/albums/...ps3dhyybdp.jpg

I replaced the three tubular ceramic Elmenco caps with modern parts (I've seen enough bad not to trust them). The .01 400 red tubular plastic H osc. cap next to the coil also has been replaced as a precaution.
http://i1095.photobucket.com/albums/...pslwp20r0g.jpg

The grounds on the video and sweep boards got a 150W iron touch up, and I also reflowed the some of chroma osc. traces (she has not lost color synch since last time).

I added the HOT cathode fuse holder, but I don't have any fuses down near the 1/4A range so it is a place holder until you pop one in. Cathode current dipped at about 200-205mA which seems decent.
http://i1095.photobucket.com/albums/...ps6uou2fvu.jpg http://i1095.photobucket.com/albums/...psai0lpw1v.jpg

I checked every resistor in the vertical section under the 2Meg max of my DMM and all were within rated tolerance. The V Out cathode cap was re-replaced with a new 47uF 160V replacement that is closer to the original 50u 150V cap that Arcanine replaced with a 100u 400V. The 80uF 450V off the vertical output Xfmr tested fine and B+ to it looks good. Hoping the Boost fix would bring it back I powered it up with no change in vert.

Some tube rolling got me this: http://i1095.photobucket.com/albums/...pszixhgprk.jpg

I think my plan of attack is going to be lift one leg of the high resistors in the vertical so my chinese component tester (which has a higher resistance range, but is more interested in the caps in the circuit) can focus on the resistors and if that fails to find fault start testing/changing the vertical stage drop caps.

Unfortunately while going thru the spare tubes (to find another vertical tube) one of the H outs Arcanine left with me managed to roll off the table and bust it's self on the floor. :sigh: I'm sorry dude, I should have been more careful.

Looking good!

As for the tube rolling off of the counter, well, I have been not only in that church but also in the same pew as well. Usually with something like a sweep tube, audio output tube (not 50C5, think ... 7027A etc.) or Telefunken 12AX7/ECC83. Yes, very frustrating and especially when we try so hard to not have it happen!

Again, looking great!

Wow it's really coming back to life. I'm glad I handed it off to you, it was indeed a little beyond me.

And which tube was it? Was it the tall RCA 6JE6? Or was it a Sylvania 6LQ6? If it was the Sylvania don't lose any sleep over it. If it was the RCA, well, better start sweating!

Haha nah don't worry I'm kidding, accidents happen. I have a couple more of those here.

Since that boost diode's been replaced with silicons, be sure to monitor it (them) for overheating.
The original part being selenium, it could handle the fast retrace ("fly-back") spike whereas silicons lagged in fast-switching ability.

It might be worth asking somebody like Mouser or Digikey if they've got Schottky diodes in high enuff voltage rating. Or you could series 'em.

Honestly, my Silvertone CTC-15 clone had to have it's Boost rect changed 5 years ago....Back then I used the same diodes to replace it, and those have been in weekly to daily use ever since without issue.....If they fail in the first 2 years of service I will be shocked.

We always used an RGP15-20 for any scan derived power supplies. It's a fast recovery 2000V 1.5A diode, and works perfectly in my CTC16, and cheap at a quarter for one diode, far cheaper than the NTE506.

http://www.fagorelectronica.com/imag...or/rgp1520.pdf

RCA specified this type in the later chassis(M134, CTC203) and once we figured out the root part number, we ordered a bunch and never looked back. great for boost diodes, and convergence diodes.

Conventional diodes like the 1N4007 and 1N5408 are just too slow, and tend to overheat.

Quick progress. The only vertical stage resistor under 2M I did not check (excluding controls which I skipped last session) was near the controls, and it was wide open....R102 150K .....I replaced it with another one on the top end of it's tolerance (t'was all I could find ATM).
http://i1095.photobucket.com/albums/...psbuismri5.jpg
Replacing it got me this.
http://i1095.photobucket.com/albums/...psp9k0ouku.jpg

I can't get linearity quite right though.....If I do the bottom (and sometimes top) is under-scanned, and centering is maxed downwards.....It's progress though.

This is the HO tube that died. I can't find any ID marks on it.
http://i1095.photobucket.com/albums/...psiluptwfp.jpg http://i1095.photobucket.com/albums/...psk09bppp8.jpg http://i1095.photobucket.com/albums/...psqgojqsvf.jpg

Oh... crap... That's one of my Dentron part numbered tubes. It's an unusual 6LQ6 tube. I tried it in the TV early on, and found it only works in HF amplifiers and not televisions despite being the same number. It's an optimized tube for HF amplification and not television.

Dentron's part number for those is D-50. http://www.radiowrench.com/sonic/so02182.html is what it came out of.

Those... are very expensive and hard to find (At least they were 9 years ago. Not looked in a long time). I forgot it was in that lot of tubes. I need to know if that RCA 6LQ6 tests healthy, if it does I can rearrange the HF amp's tubes and use the RCA as the driver.

If you don't mind test that RCA H-Out tube for me.

Don't worry dude accidents happen. I'm not mad at you. I'm MUCH happier to see a full picture on the screen of that TV then I am upset over a broken Dentron tube.

About done.

I went after the vertical linearity issue this past week. I made sure all resistors in the circuit were good and changed any marginally bad testing caps. One odd thing I found is that a cap in the output cathode circuit was listed as a .47, but the original installed part was a .15uF....I stuck with the value was installed after trying a .47 with no improvement.
I'm not proud of my replacement for that .0082 1KV orange drop....The best I could do, since I don't stock new caps over 630V, was to connect a few 2KV rated blue disc caps salvaged from 90's BPC sets in parallel for the correct value as measured on my cap testers.....Not pretty, but it should function well...It's the kind of thing I regularly put in my sets when there is nothing better on hand, but I prefer not to do that in sets repaired for others (looks unprofessional, and I'm not right there laying in wait to replace if it fails).
http://i1095.photobucket.com/albums/...ps3i5gxkgp.jpg http://i1095.photobucket.com/albums/...psyfsqyid7.jpg http://i1095.photobucket.com/albums/...psvvspsiru.jpg http://i1095.photobucket.com/albums/...pshvpzz4ud.jpg http://i1095.photobucket.com/albums/...psf6pwowni.jpg

The vertical linearity issues were watchable, but bad enough to bother me.....After all that passive part verification (with little improvement) I was about ready to give up and say the linearity was not going to get better, but then I remembered that when it still had the under-scan issue tube swapping showed linearity differences....So I swapped the vertical tube and things got better...Much better.
http://i1095.photobucket.com/albums/...pshurmilbw.jpg http://i1095.photobucket.com/albums/...pswbki3ezs.jpg http://i1095.photobucket.com/albums/...pslp4yz1lr.jpg

One odd thing that happened is that after around 1 hour on the flyback got rather hot....I know because I started smelling wax, then heard a sizzling noise from the HV cage. As soon as that happened I switched it off and opened the HV cage immediately the sizzling continued and was visually confirmed to be coming from the center of the fly windings, and a drop or two of wax had freshly landed on the small existent wax stalagmites. Many of my sets have evidence of this happening before and during my ownership, but I've never seen or heard it in action before....So I don't know whether to interpret this as normal or a warning sign. I had checked cathode current to be just under 200mA not more than 5 minutes before this happened.....
5-10 minutes after powering it off I powered it back on to do a few adjustments for 10-20 minutes....It worked fine, and it did not sizzle again.
Might be a good idea for you to drill some vent holes in the HV cage and add a computer fan to help cool it.

At this point all there is worth doing is to test all the tubes, test the lytics/replace any bad ones (if present) and reassemble it. The cans were cool after over an hour run time, and it's working like a champ, so I'm not sure the tubes and lytics need my attention.....If you want me to I'll go over them, otherwise I could skip them for speed.

Chroma synch has been reliable, but I make no guarantees that it will hold after a bumpy car ride back to your place, so I'll give you some instructions on how to adjust it when you pick it up.

If you are worried about the fly I could work on the CTC-20 after returning the 16....Then if the 16 dies (and if I can fix the 20) I could swap you a working CTC-20....

Let me know what you think.

I honestly never thought I would see that TV produce even a half watchable picture. That is as close to perfect as I'd call a set that old.

I would not worry about your repair. I can source a new cap and replace it if your repair ever fails.

As for the Flyback, I had the same thing happen where it got very hot for no reason what so ever. Judging by the wax build up in there, it's been doing that for a very long time for no real reason. Unless it's acting up internally, like windings have fused or something.

Maybe someone here has a spare CTC16 Fly I can get as a spare.

As for the rest of it, it looks like it has a great picture. Pretty excited to see it's alive and working again.

Glad your happy with it. Roundys tend to be a pain in the but to fix for first timers, but often teach them a lot about what can and will go wrong in these sets.

Do you want me to check the tubes and or lytic cans, or should I just bolt it back together and call it done?

Yeah go ahead and test them. May as well make sure they're okay before calling it gone be cause I plan to put it in to service and actually watch the thing.

Make sure you find a good 6LQ6, for me, too.

This brings back good memories from all the CTC12s-16s I worked on in my HS years, when I had lotsa time:sigh: -
thanks for a great thread

Will do.

I have only one good spare 6JS6/6LQ6 in my stocks. I kinda hate to let go of it since that CTC-20 needs one (HO socket is empty), and I have at least 6 working sets that use that tube...

I wish I could trade some other sweep tubes that I have in duplicate++ for some 6LQ6 tubes.

I sent you a DM about the tube situation, Tom. Keep your spare dude, you have a stack of sets that use it. That TV is the only I have that uses those. I have a half life one I can give you for the CTC20. It'll work in a TV fine, but my HF amp can't use it.

I believe there might be one more label less tube like the broken one in the bunch from me, along with an RCA 6LQ6, and then the 6LQ6 that was actually in the TV it self. I need to know you still have those two, I went looking and I am missing two. Pretty sure I tried two tubes.

You meant 6JE6, right? (6JS6 is 12 pin.)

Not counting the broken tube or the tube presently installed in the CTC-16; I have 3 loose 6LQ6 tubes in the boxes you brought me. One unmarked (likely Dentron), one RCA and one Sylvania. The unmarked one tests 50 on my tester (upper end of the bad tube zone), the others test in the 90 range.
http://i1095.photobucket.com/albums/...psn9nxxzg9.jpg

I tested almost all the tubes you brought me (three in the brown box and the ones in the CTC-20 were not gotten to yet). One 6GH8 in the boxes was bad. I replaced a bunch of tubes in the CTC-16 most tested healthy, but failed the grid emission and or short test of my tester....There were some weak ones, the HV rectifier, the audio output, and the 6GH8 that was NOT in the chroma osc. circuit.....Both 6GH8s were replaces since both failed in some way. Your set also now has one of two nuvistors I've had in my stocks for years....I was dumbfounded that I was able to locate one, and that it was the right type.
http://i1095.photobucket.com/albums/...ps4yxe8r7v.jpg http://i1095.photobucket.com/albums/...ps1us1lhje.jpg http://i1095.photobucket.com/albums/...psmvfwdbws.jpg

The tubes that are not weak (most of them) likely would be fine to use, but I replaced them with better ones (mostly from my stocks) anyway....You can use the old ones as spares since it was working fine with them in place. I also put two of my good 6GU7s into the spares bucket to make up for the original I ruined.
The new tubes did not significantly change the performance aside from (I think) better color lock, and reception strength.
http://i1095.photobucket.com/albums/...psubdwfeau.jpg

BTW the spares boxes contained 2-4 tubes that fit the 20, but not the 16. Do you want those or should I pop them in the CTC-20?

Yes Old_coot, you are right, I either miss-typed or jumbled the number in my head. :no:

I'm going the heck to sleep now. I'm exhausted.

The unmarked is a Dentron yeah. Internally something is different about them, that they got their own Dentron part number, and refuse to work inside of a television. So as a result they never test quite right. I know it's good because last time I transmitted with the amp on full blast, I was seeing some pretty sweet RF power.

The 6JE6/6LQ6 that's installed in the CTC16 now (Or rather when I delivered it to you) is actually from the CTC20 originally (It's hat looks more like that of a HV Rectifier). I swapped them around. Go ahead and take it out and keep it, and pop my spare RCA back in. That gives you an HO tube for the CTC20 then.

As for the tubes that DON'T belong to the CTC16, those belong to you now. I just popped a pile of tubes out of the CTC20 the final time I decided to mess with the CTC16.

Let's arrange pick up in the next week or two. Mom's car is in the shop currently getting the transmission replaced, so I don't have a warm safe SUV to transport it home in currently. And with it supposed to rain most of this week, the bed of my truck is not a good idea.

And do not buy what the tester says. Jim will chime in and agree, HV Rectifiers never test correctly. They almost always test as bad. Same thing for the Focus 1V2 tube, they test almost bad. You have to remember, the tube usually has 25kW pumping though it, so the tester can't even scratch the surface. Jim and I tested almost 10 of those tubes and they all tested pretty much the same. "Bad"

Looks great! ElectronicM done you right! Great job!

Affirmative.

.

Last night I tested all lytics in the CTC-16 for capacitance and leakage up to rated voltage with my Heathkit C3. I completely recapped the C2 and C3 (sam's cap number) cans. Can C2 had 2 leaky and one high ESR section out of 4. C3 had one high ESR section out of 2 sections so I decided to replace the whole thing for good measure. C1 tested perfect, no leakage low esr, so it was left alone.
http://i1095.photobucket.com/albums/...psgboatqy7.jpg
I powered it up with your above suggested H out tube swap and the set came on and ran with H centering jitter for 3-10 min before the width shrank greatly which prompted immediate power down. The new ho tube was drawing more than 5ma more cathode current so swapped back to tube that came in the set when I got it....Cathode current is lower and jitter is not present.

I ran it for 1 hour with h out cathode current metered the whole time (it stayed just below 200mA the whole time) and started to hear HV like sizzling and noticed screen noise/h line jitter (multiple clusters of roughly 1-3 h lines would be off center from the rest). I turned it off and the sizzling stopped with power off, opening the cage revealed very mild wax melt (compared to last time), HV winding rubber tire formed warts between HV rect cap cup and the center. It was hottest beneath wart area. The HV rect tube is a RCA 3A3C the chart calls for a 3A3A....I seem to recall once reading that some variants of that tube caused arcing in the CTC-16, but I can't recall it exactly or find it....Could that be the cause?
The tire was VERY soft and pliable in the wart area. I'm really worried that the flyback might not have long for this world.

http://i1095.photobucket.com/albums/...psuavg8klh.jpg http://i1095.photobucket.com/albums/...psfseg3ej4.jpg http://i1095.photobucket.com/albums/...psemddml6c.jpg http://i1095.photobucket.com/albums/...pswsk1deor.jpg


I don't put much stock in testers results of sweep tubes, but my tester has notes with the settings HV rects...In the case of the 3A3 it says tube good if reads 40 (in the bad scale range) or more. It read 20, and it's replacement read 90 so that is what went in.

I got the CTC-20 together and was able to get a monochrome picture and sound from it.

I'll post some info/opinions in your CTC-16 fly cooling thread latter I have a certain woman SCREAMING at me to do some remodeling work on the house right now.

I wonder if the Tire it self has become conductive? Shango066 on YouTube talks about that a lot on these old RCA sets. And it usually happens in the exact area mine is having major issues with. Right below the hat that the HV Rectifier tube goes in too.

Here is an idea: Carefully see if you can peel the tire off the flyback in the effected area, go to Autozone, or Advance Auto and get Permatex UltraGrey RTV and cover the effected area completely with a layer or two of the RTV to see if that solves the issue it's suffering. It really sounds like the tire has become conductive internally.

Look up Shango066's videos on this. He's repaired much sicker, weaker flybacks this way and it seems to hold up. It's not pretty, but these parts are unobtanium and I cannot afford to source a new fly.

And I don't want to sit with a sick lump of a TV I'm never going to do anything with. I haven't the space to just sit and let it do nothing. I only have room for one single TV this large. If the fly in this set is sick, and you have the patients and time to source a fly, fix the CTC20 and keep the CTC16.

Keep me informed.

Vidoes: https://www.youtube.com/watch?v=BUnPkymnxUw
https://www.youtube.com/watch?v=OHyQo76ySG4

it's not pretty but this might save the CTC16's fly.

I'll examine the fly more carefully to see if I can find what is going wrong.

Would you mind if I drilled a couple of holes in the HV cage so I can see in with it assembled?

The 20 has vertical problems and I have yet to address the coils that are snapped off the rear board.....I don't know if I can get the 20 to work as a color set again (those snapped coils are for color IIRC), let alone by the time you want back at (it might be extra cooperative and come together easy, but I don't want to bet on that yet)....The 16 is working fine aside from the fly issue so I want to try and fix that before I give up and focus on the 20...

I've watched the videos and am willing to try the silicone method if that is what the symptoms merit, but I want to see exactly what it is doing first.

As soon as I can look at it more I'll get back to you.