#16
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Another problem I noticed, happens in the first seconds after switching on the set. The rectifier tubes (5U4GB) light upe very quickly and the electrolytics were loaded with more than 540 volts. But they are specified only for appr. 400 volts. My suggestion: Parallel to the main switch in the set I solder a rectifier diode (p600d), so the set gets only half the power consumption when connecting with the mains. And when the tubes lighted up, I switch the set on. The voltage at the electrolytics (c105, c106) remains in the specified range. Quote:
Antenna: German tv stations transmit in horizontal polarisation, AFN is transmitted vertical. You had to turn the antenna for 90 ° to receive AFN. |
#17
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Anyway, many electrolytic caps can take a few seconds of overvoltage. Some are marked with "surge voltage" ratings. |
#18
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Last edited by andy; 12-08-2021 at 04:11 PM. |
#19
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> Very true about the transformer not wanting to see DC.
Yes, it doesn't work with U.S.-tv sets. We can do it in Germany with old tube tv's. They have no transformer and serial heating. I have lowered the AC current down to 108 volts which results in 6.3 volt heating voltage. There are less arcs than before in the horizontal output stage. With 104 volts the set is working properly, but the picture is too small now. The flyback is cool even after an hour. The total power consumption noted on the back is 350 watts. But I measured ony 260 to 270 watts (2.5 A).Are there such discrepances in total power consumption? |
#20
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I think the method of operation here with the diode is like when a diode is used without a filter cap in the "instant on" circuit of TV's....part of the AC waveform is cut off so that the effective voltage is lower.
How is the horizontal output tube current/horizontal efficiency coil adjustment? Does this set have a width switch that may be adjusted? Somewhere on an RCA color tv schematic I saw that the filament winding of the power transformer actually produced 6.8 volts? I have not actually measured the filament voltage in an RCA set to check. |
Audiokarma |
#21
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I think it would be a good idea for this guy to buy a autotransformer.{variac}.
Also make sure you have a fuse on the ac line.{mains} to be safe. |
#22
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ctc-5
> How is the horizontal output tube current/horizontal efficiency coil
> adjustment? I'm very busy at work in the moment. Next weekend I have time enough to open the set and to measure the horizontal output tube current. > Does this set have a width switch that may be adjusted? Yes, it has, I have selected the greatest width position. With 108 volts I get full screen width, see attached a photo from the sports in tv this week. Red, blue and green drive I had adjusted meanwhile. > I think it would be a good idea for this guy to buy a > autotransformer.{variac}. OK! I will see what I get here. I shall need a whole transformer park for this set ;-) First a 230 voltage variac, then the 230 volts downward transformer for 110 volts, then the transformer module for canadian 25 cycles which came with the set... |
#23
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Yagosaga- Pretty good picture, I'd say ! I hope you know how LUCKY you are to have this old set-and that it made it all the way to Germany in one piece !! It is TRULY a treasure. Furthermore, am glad you've decided to join our little discussion group here-lots of very good info & good fellowship... Enjoy !!-Sandy G.
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#24
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The most beautiful German color tv set ever manufactored was - in my opinion - the first Telefunken set of 1967, the PALcolor 708. Here is a photo of this set from a guy who lives in Wuppertal. A set with a strong A63-11X, very rare. (Most of this color crt's had a bad red gun after appr. six years.) |
#25
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Wow !! EXTRAORDINARY picture on that Telefunken !! Looks like it's in superb cosmetic shape, too-and the CRT doesn't have that ugly black band around it like a lot of Brit/Euro TVs do-is that TV tube/transistor or hybrid? -Sandy G.
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Audiokarma |
#26
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Is that a wooden mask around the CRT, or painted metal?
A beatiful set, I like the nice clean lines of those German sets. |
#27
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http://bs.cyty.com/menschen/e-etzold...alcolor708.htm Schematics can be found under "Schaltplan", click the word "Einheitschassis". You will see that this set is based upon early U.S. color tv technology with 380 volts D.C., shunt regulator and so on. Another set of this era (with the ugly black band around it) I have documentated on http://bs.cyty.com/menschen/e-etzold...z/metz6285.htm This set belongs to me, I got it before 15 years, and it has the first chromacolor tube (A66-120X) with very strong guns. |
#28
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#29
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I've always liked the "look" of German products-and the "feel". The old Grundig & SABA radio sets of the 1950s-'60s all had a VERY substantial "feel" to them-and generally, they sounded quite good, too !! My Rohde & Schwarz EK-07 Boatanchor-all the knobs have this ultra smooth, almost "buttery" feel to 'em- sorta like "everything's turning in oil". An R-390A Boatanchor, by contrast, feels, well..."agricultural" by comparison. The wooden mask on that TV is pure class, IMHO. We lost a LOT when black plastic became our god...-Sandy G.
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#30
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Transformer park, thats funny. Can you tap the 230v step down transformer to 120.
purchase an american 120v auto transformer and plug it into the 230 stepdown transformer and then turn up the auto transformer output to 110. That way you do not have to worry about 5u4 arcs and surge voltages, etc. My mains put out 122v here if i plug my ctc5s into the mains with out a variac the 5u4s put on a light show and the flyback gets hot.{ctc5s transformers sold in the us are rated at117v}Your set has a vary nice picture. Alot of work to get them going. German electronics are well made. I have 2 Grundig radios. They were easy to fix and sound great. |
Audiokarma |
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