Both audio interstage transformers are open in at least one winding and I am hunting through my junk boxes for suitable replacments. Would anyone have any of the original type ???
Looking in the book Just Astor by Rod Smith I found this radio on pages 17 and 22. It is an Astor Shielded Three of 1928 or 1929. I confimed this from the dimensions mentioned in the advertisment on page 22.
It has a Pep Punch Audio Transformer and another with Viking written on it. It looks as though there are mounting holes for another Pep Punch where this transfomer is but there is an adaptor plate for the Viking transfomer.
This is a five valve TRF receiver with three tuned stages and two audio. The three plug-in coils are from General Radio Co. and have the following written on them:
Low Loss Coil M.H.22 Turns 59 and 15.
The tuning capacitors are General Radio type 241 of 250 mmF. One of them, is missing its counter balance weight.
Should be easy to trace the circuit and to get this one going again.
The knob on the front under the opening lid is the Antenna coupling control and situated in the box each side of this are two square dry cells.
The socket on the left side of the case is for remote headphones so the officers could listen in away from the trenches. If you look closely you will see two spare crystal detectors in holders attached to the inside of the left hand side. The crystal detectors can be biased and the two crystal holders rotate so they can be switched in and out and the bias made positive or negative. The rehostate on the left is the bias control.
Note the on/off switch that is turned off by closing the lid, nothing is new I guess. The object under the two detectors is the tuning capacitor. On the right hand side of the bottom can be seen a key, a buzzer and an RF choke that picks off the RF generated by the spark from the buzzer contacts.
This tiny RF signal is used to tune the detectors. I guess way back in 1915 this was the only way you would know for sure if your radio was receiveing, there would not have been many signals floating through the air and if you were waiting for an important message from HQ, then the receiver must be ready and working. The calibration chart in Italian is still with this amazing device.
I wonder if this is the companion transmitter ?