RFT Saalburg 5170C radio (Techniek Radio/TV)
door Mike Horne 
, 29.12.2012, 13:58 (4349 dagen geleden)
Hi. I am presently working on my RFT Saalburg 5170C radio (ex GDR 1962)and I am having some difficulty in getting reception again on ukw, and a.m bands. The tubes light up ok, voltages correct. One thing that I have noticed is that if you apply a test probe to the g1 terminal of ECH81, it acts like an aerial, so thinking that the ferrite aerial coils were o/c I tested them, but they proved to be ok.
There is no ukw reception either, but there is some life in the output stage when the centre tap of the volume control is pressed.
Has anyone had experience on these radios? I can not see any breaks in circuit.
Regards
Mike (U.K)
RFT Saalburg 5170C radio
door ruudtx , 29.12.2012, 17:06 (4349 dagen geleden) @ Mike Horne
These are not very HQ sets, but anyway.
To test the output stage hold your finger to the upper gram or PU entrance, set in PU mode.
Now you must hear a loud hum. (Or alternatively connect a CD player to the PU entrance)
Hard to say what is wrong in the reception stage, but play the piano with the band switches, they might be corroded, and by working them you might clean them.
Best try MW to test.
When there is no AM reception at all probably FM won't work either. Check the voltages on the tubes ECH and EF.
RFT Saalburg 5170C radio
door Mike Horne , 08.01.2013, 12:51 (4339 dagen geleden) @ ruudtx
Hi. many thanks for your reply. My brother managed to rewind the h.t coil (fiddly job), but now I am getting high volts on the oscillator tuned circuit side and the oscillator tuning gang (stator). at times like these I need a signal tracer. There are no s/c between the two windings.
RFT Saalburg 5170C radio
door Mike Horne , 10.01.2013, 14:31 (4337 dagen geleden) @ Mike Horne
Someone kindly gave me a circuit for this radio, and surprisingly the a.m oscillator tuned circuit & gang capacitor does seem to be connected to the h.t supply via R12 resistor as well as the Oscillator anode of the ECH81. It is most unusual
Cheers
Mike