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who can repair German tube radios (1960s)

C

Chuck S.

New Member
I have a 1965 SABA 16 Konstanz. The manual says it will operate on 220VAC or 120VAC if the selector jumper and the transformer fuse size is changed. I moved the jumper and changed the fuse size, it blew the fuse instantly on 120 VAC. It had never been operated on 120 VAC, was in Germany until now. I switched it back to 220 VAC (step up transformer) and it plays on FM (no other antennas connected) albeit only on one channel. The wiring and speakers wiring resistance checks good. I suspect one of the ECL 86 final tubes is bad. So, finally to my questions, what is a good source for quality tubes (at reasonable prices) and if I can't fix the radio, who has a reputation for effectively repairing German radios of this period? It is a hybrid tube/transistor set. Any and all assistance will be appreciated. Chuck
 
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1. Tubes can be bought though any usual vendor, for example antique electronic supply. Just look up their USA equivalent on tdsl.

2. Swap the two ECL86 to check if one is bad. I put my money on it being a dirty switch contact somewhere or bad capacitor and not the tube.

3. The voltage selector isn't wired properly, or maybe being used wrong. It shouldn't blow the fuse.

4.posting your location may help find a tech
 
I did swap the tubes and the problem moved with the tube. So now shopping for a pair of tubes. I am located in the Oklahoma City area. The fuse I used was a fast blow fuse. Could it be the fast blow to sensitive to start up current draw? Thanks, Chuck
 
Any special reason you'd change the fuse size? The iron will be pulling the same amount of amps either way?
 
Voltage, not amps ... It's the amp draw that will kill a fuse.

Then again, I haven't had much experience with Euro voltage, so I may be blowing smoke here.

Least I ain't blowing fuses. <G>

Luck wit it, eh.
 
sKiZo said:
Voltage, not amps ... It's the amp draw that will kill a fuse.

Then again, I haven't had much experience with Euro voltage, so I may be blowing smoke here.

Least I ain't blowing fuses. <G>

Luck wit it, eh.
Click to expand...

A dual voltage transformer has two 120V primaries in series when it's switched for 240V, but when you switch it to 120, they're put in parallel. Each primary draws the same current regardless, so in 120V mode, the input current is double.

Make sense?
 
Wattage stays the same. Watts is volts * amps, so if you half the volts you double the amps.
 
Any halfway decent tech should be able to get yr set "Ship-Shape" w/o too much trouble. German tube sets, the ones I've been around, anyway. usually don't give much trouble..
 
This might help - contact the Oklahoma Vintage Radio Collectors Club, in Edmond, and they may be able to recommend someone. There is a Raymond Cady advertising as a restorer, but his business website appears to be inoperative. The email may still be good.

http://okvrc.org/classifieds/

Best of luck with it!
 
The problem is using the wrong types of fuses: European and US fuses are different:
(1) As noted, twice the voltage requires half the current, and vice versa. This means that the maximum current doubles when going from Europe to USA (voltage is halved so current doubles), and halved when going from the USA to Europe (voltage is doubled so current halves). The fuse is therefore half the current and guaranteed to blow. But replacing the fuse is more complex than simply doubling the rating.

(2) The continuous current ratings of the two fuse types are different: European (IEC) fuse current is specified for a continuous load of 100% of the rated current while US fuse current is specified for a continuous load of 70% to 75% of the rated current. Instead of a slow-blow type, it would be best to properly size the fuse for the load. A slow-blow is not guaranteed to fill in that 25% to 30% overload as one might expect.
​
You may verify the above by reading the documentation from LittleFuse or Bussman, and I encourage you to do that.
 
Congratulations on being an owner of a Konstanz 16, which means that it had been built in 1966. The sound of these stereo tube radios is amazing. I really hope that you'll get this unit repaired.

Greetings from the Black Forest (the "birth place" of your radio).
 
Thanks for the good wishes. The Black Forest is a beautiful place and I love to drive there, in the summer. (My wife is from Boeblingen) I finally got a correct fuse, switched to 120V,it tried to come on, the fuse blew, and it let the smoke out of something because now it doesn't work on 220V either. I think I need to find a professional to repair this radio. So I'd love some suggestions from everyone. It is a beautiful radio, it belonged to my father-in-law and I really want to have it repaired.

Thanks, Chuck
 
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