The CTC-5 Made it to Germany already!

[roundscreen]

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

[yagosaga]

Originally Posted by roundscreen

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}

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... ;-)

Originally Posted by roundscreen

... 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.ED

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.

[yagosaga]

Originally Posted by roundscreen

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.

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.

[yagosaga]

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?

[yagosaga]

screenshots, left with input, right without input.

[yagosaga]

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

[yagosaga]

Originally Posted by yagosaga

I did it tonight. The readings of the test meters:
Start: b+ 371v, horizontal output current 210ma, high voltage 21kv ...
60 minutes: b+ 371v, horizontal output current 210ma.
No significant changes. ... 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.

Tonight I have checked the flyback of my PALcolor 708, the first PAL color tv set by Telefunken, which has nearly the same currents like the RCA CTC-5 (380 volts). After one hour the flyback was much more as hot as the flyback of the ctc-5. One can't touch the flyback of the PALcolor for a longer time because it is too hot! In comparison the ctc-5's flyback was really cold.
Both sets are operating with 380 volts in the horizontal output unit (anode voltage for the horizontal output tube), the ctc-5's current shouldn't extend 220 ma. The PALcolor has 260 mA horizontal output current. This indicates that the growing temperature of the flyback of the ctc-5 is in the normal range.

[yagosaga]

Today I have soldered an octal connection for the deflection yokes to operate the chassis outside the set (see photo). I tried to adjust the horizontal output current by turning the core inside the horizontal tuning coil (horizontal linearity). But I can't turn the core, it sticks. How can I loosen the core without destoying the coil? Here by us we do that with a special oil which is a mixture of oil and some kind of acid. But is this the right way for fixing such vintage devices?