Sorry, but I have some simple (and silly?) questions. When I remove the chassis, I can't get it easily into working condition outside the set, because the cables (connection to the deflection jokes) are too short. The only possibility is to turn it around 180 ° and put it with the back half into the set. Do you have any tricks? Is there anything to hanging in the chassis while servicing in operating mode?

With 114 v ac and width control at center position, the sides of the picture fill the screen, see
http://bs.cyty.com/menschen/e-etzold/1a.jpg

For checking high voltage current and the other measures I need some help to put the chassis into a suitable service position. In the moment servicing is very pedantically.

I am currently working on two CTC-5s and have the same problem with the chassis. RCA produced a set of extension cables that allowed the chassis to be set on the top or side of the cabinet. It is possible to make a set of these but the hardest part is to find the connectors for the convergence plug. You probably could back the chassis into the cabinet but the anode lead may not be long enough to get into the high voltage cage.

Steve

Yagosaga- Awwww, man, that's a nice picture !!! You've done an EXCELLENT job...Congrats are in order. I was a bit resentful at first that one of these guys had left the country, but now that I see how you've treated it, the "love" & respect you obviously show towards it, I don't think it could be in better hands.... My hat's off to you, sir !! -Sandy G.

| ROTFL |

- An old tv serviceman here in Brunswick told me, when he was servicing these old color tv's in the 1950s and 1960s in the U.S., they fetch only the chassis from the owners, not the whole set, and hang it into the van. In the repair workshop they had a frame, where they hang the chassis in. At the workbench they had a crt with different adapters, so they could connect the chassis. Then they repaired it, and if one could find the failure within a specified time, he has to change with another serviceman. After repairing they brought back the chassis and put it into the set. (But I don't have a RCA workbench... ;-)

Wo ist Brunswick order ist das Braunschweig? Es tut mir leid mein deutsch is nicht gut aber ich werde Deutschland in Mai besuchen. I will send you a PM so others don't get upset over my poor use of German!

Bis dann,
Steve

Thank you very much for your friendly words. Yes, I love these old sets since decades. For me it is a honour to serve one of these treasures. We usually don't get no full tube color tv set here in Europe. The eldest sets are hybrid sets. And I remember when I was a pupil and later a student 25 years ago, I repaired many color tcv sets from the 1960s. Most of them had weak crt's, with bad red guns. I have learned to revival those sets without any brightener like you know in the U.S., alone by fine adjustment of color drive, screen background etc.. in this case here with the ctc-5, it is much easier. It's crt ist still strong. And the owners before did a good job with recapping and cleaning the chassis.
This is not the only ctc-5 here in Germany. A friend of mine has one (but not in working condition) and even a ct-100.

It is Braunschweig, near Hanover. You can write in English to me. Deutsch is a terrible language (this already said Mark Twain). I can read English much better than write it.
When I come to America the next time I hope, I can visit the Early Television Foundation. (Some members of my family live in the french part of Canada.)

It is 21kv (with dark screen), 20.8kv with bright screen. The next values follow when I have enough time to remove the chassis and find a solution to operate it outside the cabinet.

Eckhard. That is wonderful. Such a Great picture on that set. looks to me you know what you are doing. If i recall correctly. I put the chassis on it's side. The hi volt cage on the bottom. The yoke wires are short but you can turn the chassis so the wires reach. Please look out for the yoke socket. It moves when you plug the yoke in or out. {Not mounted to well} Convergence wires. hi volt and the crt wires should be long enough. {please be careful of the crt}. Also connect a ground wire to the ground tabs up front were the chassis slides in. For extra protection you can use rope or wire to hold the chassis in place. Tie one end to the chassis and the other to the cabinet. { like when you tie the christmas tree to the wall so the cat can not knock it over} This may sound strange, but Next to the transformer park I want you to build a test meter park. One meter for b+. One for horz current and your hi volt probe. Once you know all the readings are ok {horz-reg current,} Put the chassis back in the cabinet, Hook up the meters and run the set for 15 minutes. Check the readings, shut the set off ,discharge the high voltage {ground wire to the 3a3} and put your hand on the flyback{ It should not be hot}. Turn the set back on and do it again. This time run it for 30 minutes. then 45 etc. When you hit 60 minutes the fly will be warm not hot. check your meter readings. Look out for drift:{ big changes in current reading, b+ and hi voltage} I like watching the meters. How the readings change with the action of the picture or when the set warms up. Do this for a week or so . get a feel how the set runs. That way you know there is not a problem. I had meters on mine for a month . The ctc 5 runs like a bitch once you get the bugs out of them. I haven't had to do any thing to mine in years. Such a cool tv .

ED

I'm not really happy with this construction. The ctc-5-chassis is the heaviest tv-chassis I've seen in my life (and the sets I've seen are unnumbered in the last 30 years). It is still very strange for me. One moment of inattentiveness and the falling chassis hit the neck of the crt, and the game is over.
I see two solutions:
- First I construct a wooden frame for the chassis outside the cabinet, which holds it in a safe way.
- The second solution: I solder some wire at the measure points on the chassis and install a "soldering border" (= correct words? In German we say "Loetleiste") inside the cabinet for the wires. Every wire gets a paper mark with it's connection on the chassis. So I can put the chassis inside again and have measure points for future evaluations. I prefer this second solution.
With the test meters, there is no problem, I have enough, and I have enough connection wires too (in German we say "Krokodilsklemmen"). And if I haven't enough, I ask my 11 year old son... ;-)
Yes, to get a feeling is the most important thing. For every vintage set which I have repaired I needed time to get a feeling for it. At first to understand the schematics, then to watch the set in operating modus. American and German tv sets are very different. The Germans are not so heavy and robust but seem to be more complicated, especially the color hybrid sets.

Yes your solutions are much better. Here we call the old chassis boat anchors.

(= correct words? In German we say "Loetleiste")

I believe that a Loetleiste is a "terminal strip." It is interesting that in German you call them Krokodilsklemmen (crocodile clamps) we call them alligator clamps!

Steve

That's really interesting! You have alligators in your country and therefore you have alligator clamps. The correct German expression has to be lizard clamps (= Eidechsenklemme), for we have neither crocodiles nor alligators but only small lizards in our country. But "Krokodilsklemme" sounds much more exciting. See you later, alligator...

I think I recall reading a German patent about "Bildroehren" (picture tubes) that featured "electronenkanonen" (spelling?) I got a kick out of picturing large-bore cannons (we would say electron guns) in the neck of the tube.

Congratulations on the great results you are getting.

I did it tonight. The readings of the test meters:
Start: b+ 371v, horizontal output current 210ma, high voltage 21kv
15 minutes: b+ 372v, horizontal output current 210ma
30 minutes: b+ 374v, horizontal output current 210ma
45 minutes: b+ 372v, horizontal output current 210ma
60 minutes: b+ 371v, horizontal output current 210ma.
No significant changes.
High voltage vary with brightness and contrast. With brightness and contrast at minimum it is 21.3kv, in "normal" position with the best picture it is 21.8kv, but with contrast and brightness at maximum I get a bright and wishywashy picture. High voltage declines down to 13.9kv.
The flyback was a little warmer after 15 minutes and very warm after one hour, not hot, estimated temperature appr. 50 to 55 degrees celsius.

No video signal, color and audio ok
 

While testing this morning the video signal disappeared (with a delay time of one or two seconds). No sync, picture with full contrast control has few contrast, and looks inverse, like a film negative. Sound ok, color seems ok too. With no tuner input signal, a contrast rich noise (snow) is on the screen like before in such cases. I assume a defect video detector (1N60).
Testing the first video amplifier tube 6aw8: first grid and positive end of video detector 2.7v instead of 19v, kathode 8.2v instead of 22v, anode 217v instead of 148v, 2nd grid 188v instead of 170v.
Kathodes of the crt appr. 310volts. Do you know this failure?

screenshots
 

screenshots, left with input, right without input.

video ok
 

I have found the defect. It was not the video detector but the A.G.C. circuit. The A.G.C. amplifier (pentode of the 6U8) was very weak (tested with Funke W19). At the anode there were only -1v. It has to be appr. -31v. With the new 6U8 (european ECF 82) the set is working properly again. -76v (??) at the anode.
The schematics for the ctc-5 are online here:
http://www.mcmlv.org/Archive/Radio/CTC5A.pdf

Eckhard. Please check c127 470 mmf.{pf} This cap might be leaking. That may be why your -31v is showing -76v. Could you please tell me the chassis number of your set. ctc5 a,b etc. The schematic on line does not match up with mine. I must have the wrong one. Also i would like to try and lower the horz current .
Ed

ED: C127 I have checked yesterday with a voltmeter, but it seems to be ok. I will test it with a capacitor tester (500v, 1000v) or will renew it the next time when I remove the chassis.
The chassis number is CTC 5E, RVA L4, 2746443.
I have checked the horizontal oscillator tube V601 (6CG7) with the Funke W19. I found a short between heating and kathode in one triode system.
Another defect appears while watching strong red colored parts of the picture. When I increase the color contrast, red peaks became black. This also happened with green peaks, but so evident. V703 (12AT7), the G-Y and R-Y demodulator, was also bad, had low emission on both systems, I have renewed it.
BTW: I have a field service manual as a pdf file (appr. 7 MByte), I can send it to you.

Eckhard. Please send your manual to [email protected]. Thank you. Also i am going to dig out my ctc5. I want to be on the same page. If C127 looks like a brown or tan square disk with color dots on it. Just replace it. Did the replacement of the 6CG7 do anything to the horz current? C114. The cap you were talking about {.1 } Bugs me.{Now that i know what it is}. I would like to take a closer look at it when i get all the correct info.
ED

Yes, it looks so. I havbe replaced it with a 1200v d.c. capacitor.
No. But I have some other news. There is a 1 meg resistor R105 in the schematics between R131 (to the grid of the 6CB5) and the kathode. This 1 meg resistor is missing in this set. I have added it. But now horizontal output current increases up to 230ma. I will cut R105 next time.
Voltage at grid is -22v, but has to be -40v according to the schematics. The resistance between grid chassis ground is appr. 300 - 400 K. This seems to low for me.

Vary interesting. On the manual you sent me that resistor shows R165 Someone wrote omit on it in ink. -22v is low. When i get out of work I will measure that voltage on mine and see what i get. If i recall correctly i think it was approx -35v. Also i will take a resistance reading. How is the horz sync? Do you have to turn the knob one complete turn before the horz sync goes out?
Ed

Thank you very much for your support! This manual doesn't belong to this set. But the remarks are interesting, they show me the weak points of the set.
While watching the meters during the lunch break, currents increased up to -29v with 200 - 210ma current. I will change R601 (470K) in the evening after work to 800K to see what an effect this has and hope to move the working point of the 6CB5 to the lower flank.
Yes. I can turn it one and a half turn before sync goes out.

The grid control of V104 (6CB5) is connected over R601 with the brightness control of the set (R101A). This is important to know.
Last night I have changed R601 (470K) with a 900K resistor, horiz. current was only 170-180ma, grid of 6CB5 has -35v to -39v. This seems OK, but brightness is overloading, at minimum brightness control there is full brightness and picture width changes enormously with brightness adjusting.
Later I analysed the horiz. oscillator section. I have already noted that R165 at the grid of 6CB5 is missing. But this was wrong assumption.
They have moved R165 on the Hor. Oscillator Assembly plate (PW 600). "Ground" of R165 is the grid of the 2nd. triode of V601 (6CG7). R165 can switched off/on by a cable link on the printed circuit. (See the blue colored part of the schematics here). I have changed the location of R165 according to the origin schematics of the manual (yellow colored part). But horiz. current exceeded 230ma and grid of 6CB5 has -20v. This was the wrong way. I have restored the origin circuits of the set (with R165 at grid of V601, blue colored part).
At the 2nd. grid of V601 I measured -40v instead of -68v (or maybe -88v, it is not clear printed in the manual). I assume that the oscillator doesn't provide a full amplidute sine wave.

I checked my field service guide and it shows the resistor connected to the grid of the 6cg7. What you have in blue. The voltage on the grid is -88 volts.

Thank you very much for that information. Yellow is the layout of my service manuals here (only as pdf-file) and blue is the actual layout of the printed assembly here on the chassis. Note:I have copy and drawn here the blue parts into the photo of the schematics! In this ctc-5 the printed assembly PW600 was changed. This change was not documented in my service guide.
Yesterday I have tested the 6CB5. With 40 percent it was at the lower end of the scale. I have renewed it. Now I read -24v at the grid of the 6CB5, horizontal output current now is 190ma (with 114v ac) and 170mA (with 105v ac, for comparison see my posting of 02-12-2005 12:16 AM). Picture width is wider than the screen in the middle position of the width switch. Flyback is very warm, but not hot after one hour.
At first glance all seems OK now. But I think, -24v at grid of 6CB5 is still not enough. There is too much d.c. in the horizontal output unit. It should be -40v. When I get a new damper I will change it too (usually I change only horizontal output tube and damper together).
At the anode, pin 6 of the 6CG7 (horizontal oscillator, V601), I read 140v, should be 235v according to schematics. At the grid (pin 7 of 6CG7) I read -40v, should be -88v according to the reading in your field service guide. The 6CG7 seems not ok, I have found a short between heating and kathode. But kathode here is connected with the ground of the chassis.

Eckhard. please check C611 and C610 82mmf

Same thing as before. If they are a brown or tan cap with dots. {Replace them}. They won't be as large as the one in the agc.

Replacement of the caps c611-c610 and a horz realignment may help bring up the grid voltage at the 6CB5. Also give the cap off pin 7 of the 6cg7 a check. 270 mmf{pf} I can not read the # of that cap. Sorry about the goofy posts.{kid running around}
ED.

No goofy posts but elementary help! Thank you for your support. These caps are the usual suspects... They were already recapped with small brown dotted ceramic caps. But I think the voltage rate seems not high enough, there are high currents in this oscillator unit. And I will change them with higher rated polypropylen caps. I'm just on the way in the city and will got to the next electronic store.

This tv set is an exercise in being patient (like most of the vintage sets..)

c611and c610 recapped, c603 too with 0.01 at 2kv. c606 (pin 7, grid of 6CG7) tested OK.
c603 is designed for 1kv. The results: -23v at grid of 6CB5 and horizontal output current 190ma after recapping. The usual suspicious are OK.

Values for the first triode of 6CG7:
!!! The reading of the test meter at the grid (pin 2) is -3v instead of -27v. !!! No sync while contacting with the testmeter - it was not possible to adjust correct synchronisation while testing.
!!! Testmeter at kathode of 6CG7 (pin 3) reads +12.6v instead of +5v. !!! Ohmmeter reads 228K between grid and ground, this seems OK.
Between grid (pin 2) and ground 1.27M, has to be 1.3M according to the manual. OK.
R608 with 156K, OK.
All capacitors on the horizontal oscillator unit are now freshly recapped.
6CG7 used and new, tested with 10ma, good.

c609 has 0.0047 instead of 0.047. The guy, who had done the recapping job before must mistaken it. (Or not?). I replaced c609 with 0.047. Now -18v at grid of 6CB5 and horizontal output current 210ma.
Without c609 I read -22v at grid of 6CB5 and horizontal output current 200ma. What are the correct data for c609?

c604 ist OK with 1000 (or 1nF).

I checked c609 on a sams manual and the manual in the computer. Both show .047. C604 is 1000pf . Checked both manuals on c604 too. Dug out the other ctc5.{ctc5e} This set is a junker I got from a buddie who is into radios. He did a re cap and ran the set without checking the horz current and the flyback overheated. He quit and gave it to me. I did a trade for some radios. This set has been a trouble since day one. Never could get the horz size to fill the picture like the other ctc5s and the current was hard to control. Here are some readings on it. AC 110. b+ 292v. Drive voltage -27v. current 205ma. hv 21kv with normal brightness. As you can see b+ and drive voltages are low. Maybe This picture may help you. Throw it on your hard drive and zoom it up. It shows how to adjust the drive voltage. I will do some more work on my set and get more voltage readings on the 6cg7. It was not happy when I turned it on. {Been many years since it was turned on} Have to check the power filters. {may be one reason why the b+ is so low} and the color looks crap. Keep picking at your set like you been doing. I am sure you will get it to work the way you want it to.
ED

It seems that the problems of horizontal output are not my problems alone. Thank you for your comment and the scanned page, which helped me to understand how the sawtooth-waveform is generated in the horizontal oscillator. This gave me the kick to check the older RCA chassis too. And what did I found? ctc4 and ct-100 had both a horizontal drive control. The remaining circuits are nearly identical. The 6CB7 have the same kathode grid voltage difference, appr. 50v. But in the ctc-4 there is an extra -29v source in the power supply only for the 6CB5. No grid voltage of the 6CB5 was used for brightness control level like in ctc-5 and no d.c. connection to the grid of the horizontal oscillator. Between c154 (ctc-4) and the grid is only one R160 with 470K to kathode. The ctc-5 seems more puzzling here.

It is interesting to know whether the ctc-4s had the same trouble with high horizontal output currents and low drive voltage at the grid of the 6CB7. Does somebody here has some experiences with the ctc-4? Can somebody here provide the schematics for the ctc-7 or ctc-9?

I have added a 0.047 cap again to c609. At kathode of 6CG7 still I read 12v. But there is very low high voltage but very high focus voltage (it's arcing). With 0.0047 the set is running "properly". Another point: c611 is critical. instead of 82 it was replaced with 100. I have replaced it with 82, and horizontal current increased a little.

The schematics of the ctc-5 are much more interconnected with other units in the set than the former models. One possibility is to insert a drive control like in the ctc-4.
The other possibility is to renew c609 with 0.047 and do a complete re-adjusting of the horizontal oscillator and output unit. On page 17 of the service manual is a method how to adjust horizontal output correctly. I have an old oscilloscope from the 1960's on the attic, which I will arouse again to life for that.

Eckhard:

Here is the horizontal section of the CTC-7. I also have the schematic for the 9. Is this the only part you wanted to see or would you like the entire schematics?

Steve

Are you using a vtvm or dvm to measure the voltage? A vom will load the circuit at pin 2 since it's input resistance is lower than that of the circuit you are testing. You need to use a vtvm or a digital meter or scope to check the voltage at pin 2 of the 6cg7.

R608 shows 100k not 156k.

My guide shows c609 as .047. However they have been known to be wrong.
It certenly seemed to work better with the .0047.

I do notice in the list of production changes that on some sets they omitted R602 the 1 meg resistor.
I also notice that r603 which shows 82k has been 100k 120k and 150k.

What is the plate voltage on pin 1 of the cg7? It should be 300volts? I would double check the values of the resistors in this circuit especially r 608. Resistors are cheep I might just replace them. I know it is shotgunning, but sometimes it is the only way to find something breaking down at full voltage.
I do not think I would add a drive control since none was there in the original design. On the ctc 7 they added a drive control. They lifted the ground end of r603, changed its value to 100k and connected it to .0033 cap then to 250k pot to ground. There are some other changes to the 6cg7 circuit though and it used a 6dq5 output tube.

Eckhard. I have some 6Cg7 readings withAC@110. B+292v{filters check ok} horz current 205-206 ma. horz drive -28 {changed some caps}.
pin 2. - 18v
pin 3. I get .140 dc and 20v when I switch the meter to ac {may be my meter is loading it down}
pin 6. 200v { meter loads this line down too and horz lock goes out}
pin 7. -65v
The picture dosen't look that great but you can see the bars look almost the same width. The sides of the screen are in a little with the width set to the middle. When I turn the width to high the bars look normal with an increase of 1ma on the horz current This set has a 21fjp22 in it. When my buddie had it The crt blew out when the flyback started to cook. Took out the 6bk4 and other parts too. I used this cabinet as a jig to repair my other chassis. Did not want to work around the 21axp crts.{Accident prone}. Question. Have you done any adjustments to the horz lin coil? You may want to try and put your finger on the horz lin coil to see if it gets warm or hot run the set for 15min then check it. You can take the screen off the bottom of the set and be able to put your finger on it. Also if you adjust the horz drive up. Do you get a fold over on the right side of the screen?
ED

Here is a picture of the chassis#

Thank you for all that informations. Last night I soldered new resistors on the horizontal oscillator unit. When brought the set in operating mode again I read that horizontal output current increased up to 450ma.and I switched off the set at once. At the grid of the 6CB5 I found appr. +300v. !!! When I evaluated the unit I found a (small, just invisible soldered) short between c603 and R165 (on the printed circuit). Shame about me! Full B+ at grid of 6CB5. I tested 6CB5: short between screen and grid. After repairing +5v remained at the grid of the 6CB5. Next I will remove the chassis and will operate it outside the set, only for repairing and servicing the horizontal oscillator which is not working. Hope that nothing important more is defect - never touch a running system... hahaha.

Hi folks! The ctc-5 is working again!
Beside the defect 6cb5, which I have replaced with the old 6cg5, I found a defect at the sine coil. Because of the extreme positive voltage at grid of the 6cb5 this voltage is linked to the grid of the 6cg7 too (via R165). The high current of the 6cg7 had burned out the sine coil. I found an interuption at one feet of the coil which could be soldered carefully.
For testing the chassis without crt and horizontal output unit I inserted a 4K 50watts resistor between chassis ground and +385v and used the 105v ac source to get clear +385v.
Without 385v d.v. at the horizontal output unit, I have now the correct -89v at grid of 6cg7 and -39v at grid of 6cb5 !!
Then I inserted the chassis into the set, testmeter at horizontal output current and grid of 6cb5, high voltage probe. The results: horizontal output current is 208ma, picture has full horizontal width, even in the smallest switch position.
The next readings: -37.8v at the grid of 6cb5 !! 19.25kv with the hv probe.
Some remarks: R608 has 103K. Plate voltage on pin 1 of the 6cg7 is 293v.
While renewing the resistors I found that R603 has 90K, should be 150K I have soldered a 150K resistor instead of 90K!
The other resistors had no out-of-tolerance values but some of them were crumbly, they broke while removing.
In the next days I will watch the set and its flyback how warm or hot it will be after 15, 30, 45 and 60 minutes.
Thank you for all your support and patience with me.

Mistakes, don't ya hate that. 450 ma now thats some horz drive. When I solder boards I take a small screwdriver and scrape the board around the traces and connections I worked on. Since i am a walking mistake I double check all the work I do.
and find them way to many times. When things go bad, Some times it is best to take a break from it.