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Sekretär III 697/75GWU 3D

Sekretär III 697/75GWU 3D; Stern-Radio (ID = 2457222) Radio Sekretär III 697/75GWU 3D; Stern-Radio (ID = 419173) Radio
Sekretär III 697/75GWU 3D; Stern-Radio (ID = 419175) Radio Sekretär III 697/75GWU 3D; Stern-Radio (ID = 419174) Radio
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Sekretär III 697/75GWU 3D; Stern-Radio (ID = 2457222) Radio
Stern-Radio: Sekretär III 697/75GWU 3D [Radio] ID = 2457222 1400x1050
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For model Sekretär III 697/75GWU 3D, Stern-Radio Sonneberg, VEB, RFT; SONRA; -vorm.: EAK (Ostd.) - ex. AEG
Country:  Germany
Manufacturer / Brand:  Stern-Radio Sonneberg, VEB, RFT; SONRA; -vorm.: EAK (Ostd.) - ex. AEG
Year: 1960 ?? Category: Broadcast Receiver - or past WW2 Tuner
Valves / Tubes 6: UCC85 UCH81 UBF89 UABC80 UM80 UL84
Semiconductors (the count is only for transistors) Tr.Gl.=Metal-rectif.
schematic requested
Main principle Superheterodyne (common); ZF/IF 468 kHz
Tuned circuits 6 AM circuit(s)
Wave bands Broadcast, Long Wave and FM or UHF.
Power type and voltage AC/DC-set / 220 Volt
Loudspeaker Permanent Magnet Dynamic (PDyn) Loudspeaker (moving coil) - elliptical / Ø 22 cm = 8.7 inch
Power out 2 W (unknown quality)
from Model: Sekretär III 697/75GWU 3D - Stern-Radio Sonneberg, VEB,
Material Wooden case
Shape Tablemodel, with any shape - general.
Dimensions (WHD) 560 x 315 x 185 mm / 22 x 12.4 x 7.3 inch
Notes TA nur mit Trenntrafo möglich.
Net weight (2.2 lb = 1 kg) 7 kg / 15 lb 6.7 oz (15.419 lb)
Source of data - - Data from my own collection

Model page created by Klemens Rhode. See "Data change" for further contributors.

All listed radios etc. from Stern-Radio Sonneberg, VEB, RFT; SONRA; -vorm.: EAK (Ostd.) - ex. AEG
Here you find 383 models, 305 with images and 279 with schematics for wireless sets etc. In French: TSF for Télégraphie sans fil.


Forum contributions about this model
Stern-Radio: Sekretär III 697/75GWU 3D
Threads: 1 | Posts: 3
Hits: 1309     Replies: 2
stern-sonn: 697/75GWU 3D; Sekretär III
Timo Haveri
  1 I'm restoring a Sekretär III 697/75GWU 3D radio. There wasn't a schematic for this model in RMorg but I used a schematic for model Sekretär III 697/62GWU which I believe to be close enough. There are no component values in the schematic and I need to know the value of one resistor. It is burned open and the markings are no longer visible. I think it is R11 in the schematic (in the lower left corner, antenna circuit). I have no idea how it got burned. There is no visible damage in the other components.

Also I removed the 50 + 100 uF electrolytic capacitor can but I forgot to look which one is the first and which one is the second filter. I'm guessing that the 100 uF is the first. Am I right?

The final question is about the half wave selenium rectifier. I measured its resistance with a digital ohm meter and I got 1.3 megaohms in the other direction and 1.6 megaohms in the other. I assume that it is bad?

All answers will be greatly appreciated.

Martin Renz
  2 Hello Timo,
you can use the schematic of the 697/77 GWU Sekretär 4 modell. The component values are added there.

You can't check a selenium rectifier with a digital ohm meter. Check the anode voltages instead. If they all are too low, or the rectifier gets hot, this indicates a possibly bad rectifier.

For more information look here and may be here and here (about restauration in general by Hans Knoll)
Timo Haveri
  3 Thank you Martin. I have checked selenium bridge rectifiers before with a digital meter and they behaved just like normal diodes. None of them showed reverse leakage but this one does. I'll try carefully how the original rectifier performs. I already tried the radio with a silicon diode + resistor and it worked but quite weakly. It seems that the volume potentiometer has some problems. And it needs a new UM80 eye tube. Maybe some other tube is also bad.

Stern-Radio: Sekretär III 697/75GWU 3D
End of forum contributions about this model