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#1
12-18-2006, 05:21 PM
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Graetz Faehnrich color
Hi folks,
one year ago, I got a hybrid color tv set. It was the Graetz Faehnrich 2441. I remember the good old days when I was 15 years old, in 1975, I saw this set as a new one in the shops. This was the last delta-CRT color tv set with tubes on the chassis, which was sold in Germany. This set here had a broken CRT (510CKB22) and a broken chassis. The plates of the signal chassis and the deflection chassis were broken. I soldered all broken copper and wire connections. Last week, I had a telephone call. Somebody from the technical university told me that there is a spare CRT on the universities' dump. I fetched it and tested it. It was a Hitachi CRT with 0.8 mA red, 0.7 mA blue and 0.6 mA on the green gun. Together with my son, I disassembled the set, removed the broken CRT and installed the other CRT. After assembling the set and switching on, the screen was total green with no blue. At first, I thought, the CRT is bad. But I have measured it. It was OK. Then I measured the CRT's screen voltage. It was 400 volts for red, but only 100 volts for green and 50 volts for blue. When I turned blue screen voltage to highest level, the crt's screen became dark. I checked the potentiometers for the screen voltage (sometimes they lowered their values), but they are OK. I removed the crt plate and checked the screen voltages without operating the crt. The same effect. The solution I got from the man who told me about the spare crt on the universities dump. He wrote to me that he often had troubles in the past with the switches for the screen voltages for purity adjustments. In fact, the fault was a small grime trace on the switches with which one can switch off the screen voltages for blue and green. After removing the switches, the set operated well. http://bs.cyty.com/menschen/e-etzold..._inBetrieb.jpg Eckhard 
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#3
12-18-2006, 06:15 PM
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#4
12-19-2006, 06:26 AM
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The show on the screen is Yellow Submarine.
I have added a photo of the switch for the screen grid voltage. In normal light (picture A) one can not see the grime trace. But with flashlight (picture B) it is visible. It is only a small trace. But it acts like a Zener diode. With a usual Ohm meter, all things seem to be OK. But when some hundred volts are present, the trace become electroconductive. Below a hundred volts the trace acts like an insulator. So the trace keeps the voltage of around 100 volts, equal whether there are 200 volts or 700 volts at the switch. Eckhard
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#6
12-19-2006, 08:39 AM
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Hi Eckhard.
The color on your set is awesome. How many sets do you have in your collection now? What are the two sets I see behind the Gratz Faehnrich? One looks like your ctc 5. Does your son show a strong interest in your collection? Ed
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#7
12-19-2006, 09:39 AM
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The sets behind the Faehnrich are the RCA ctc5 and the Saba T2000color. I have appr. 25 tv sets in my collection (including the small tvs and pocket tv sets).
Here are some more photos from chassis, the broken crt and the set. Eckhard
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#8
12-20-2006, 07:58 AM
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The yoke sorta looks like one you would see on a computer monitor but not as big. Cool looking set.
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#9
12-20-2006, 12:47 PM
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These yokes are common in sets of this era. I have put away the yoke as a spare one.
BTW: The Faehnrich has a rectifier tube for the high voltage but no shunt regulator. The beam current is limited only by the output of the luminance amplifier. My son has some interest, but his main interest is assembling of PCs and sell them. In the moment I have a Philips D22K862 with the K7 chassis on the bench. I have fixed the tuner voltage (33 volts). But there is still no control of contrast, brightness and color. The wires et cet. seems to be OK. The next time I have to measure the signals. Eckhard
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#10
12-20-2006, 07:03 PM
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luminance amp? There is no high voltage regulator in your faehnrich.
That is wild, What does it do when there is a change in line voltage? {frig or washer turning on} Is there a regulator on the b+ line? Your son may get more interested in the vintage sets when he gets older. Most collectors will tell you that they want a set that they watched when they were young. My family had rca color roundies when I was young and now I have a house full of them. Making money assembling computers is good too. Philips K7, Is that a round color set or rectangular? If I recall, You have a friend that has a round color set with a k7 chassis. It looks like it is in perfect condition. Vary cool looking set with a good picture. Ed
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#11
12-21-2006, 03:46 AM
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Quote:
http://bs.cyty.com/menschen/e-etzold...aetz2441_1.jpg http://bs.cyty.com/menschen/e-etzold...aetz2441_2.jpg http://bs.cyty.com/menschen/e-etzold...aetz2441_3.jpg http://bs.cyty.com/menschen/e-etzold...aetz2441_4.jpg http://bs.cyty.com/menschen/e-etzold...aetz2441_5.jpg The high voltage unit is in the third part. Quote:
http://bs.cyty.com/menschen/e-etzold...4inBetrieb.jpg The picture of this set is awesome. Eckhard
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#12
12-21-2006, 08:11 AM
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Sorry if i sound stupid. I took a look at the power supply. No regulator.
It is interesting, Looks like there are two power supply in your set. One part of the power supply is connected to a transformer. The other part is connected directly to the ac line{220}. Does you set have a remote? The beam current circuit looks like a brightness limiter circuit I see in sets here. Brightness limiter controls the beam current so the picture will not bloom due to to much current to the guns. {to much brightness}. When I get home from work tonight I will look at the schematics closer. You set is complex and I like them. Thank you for posting the schematics. Well I had the k part right on the set you are working on. Did you find what is wrong? Does the 33 volts that goes to the tuner go to any of the other circuits in the set?
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#13
12-21-2006, 08:34 AM
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Ed:
the Faehnrich was a very cheap set. All what is not absolutely necessary was omitted. Therefore I estimate it not as complex. The Philips color tv sets are much more complex, Saba also. The Graetz color tv sets of the generations before had two line output transformers, one for high voltage with a regulator circuit (no shunt regulator) and one for the horizontal deflection. The line output unit of the Faehnrich is designed like the b/w horizontal output units. In my opinion it is very similar to the GE portacolor. Perhaps a shunt regulator might not be necessary because the beam currents are lower then in the sets before. The CRT measured not good, but useable. But the phosphors seem to be very efficient. The good picture might not depend on high beam currents but on effective phosphors. A wired remote control can be connected. No ultrasonic remote. In the moment I have no time to work on the Philips K7. Xmas is coming and I have to prepare the Xmas services and a lot of presents for the family. Perhaps I found some time around midnight to make the measures at the luminance controls. Eckhard
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#14
12-28-2006, 04:17 PM
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Quote:
A web page about the Faehnrich is ready, see http://bs.cyty.com/menschen/e-etzold...h2441color.htm And in the next days a web page about an East German experimental color monitor will go online. Due to server troubles I could only upload the photos of this monitor, which is appr. 1960 and fitted with a 21CYP22: http://bs.cyty.com/menschen/e-etzold...arbmonitor.htm Eckhard
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#15
12-29-2006, 09:18 AM
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Even with weak contrast the k 7 has a nice picture. What was the reason that the ground was missing to the controls? Broken wire or a trace on the board?
Are you working on the east German set? Also why is the 21cyp22 yoke and convergence assembly turned to the left? Vary interesting.
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