UK Vintage Radio Repair and Restoration Discussion Forum - View Single Post

ms660 · 9th Nov 2018, 5:21 pm

If the problem is narrowed down to the receiver and cleaning the switch contacts doesn't sort it out do a hum injection test with a meter probe, the gram input on the schematic in the link that was posted is socket III, socket II is ground and socket I is the radio signal output for a tape recorder etc. The switch contacts in the circuit and the switch layout drawing are shown with the receiver switched to the Off (Aus) position, the switch layout drawing is as viewed from above, both MW and LW buttons have to be engaged for the gram input to be selected.

As an aid (if needed) here's the signal flow path from the gram socket in the schematic through the switch contacts (numbers given) when the gram function is selected:

Socket III >> switch contacts 64--65>>switch contacts 49--50>>switch contacts 18--17.

Lawrence.

9th Nov 2018, 5:21 pm	#29
ms660 Dekatron Join Date: Apr 2011 Location: Cornwall, UK. Posts: 13,454	Re: Reviving Radio in old German Radiogram If the problem is narrowed down to the receiver and cleaning the switch contacts doesn't sort it out do a hum injection test with a meter probe, the gram input on the schematic in the link that was posted is socket III, socket II is ground and socket I is the radio signal output for a tape recorder etc. The switch contacts in the circuit and the switch layout drawing are shown with the receiver switched to the Off (Aus) position, the switch layout drawing is as viewed from above, both MW and LW buttons have to be engaged for the gram input to be selected. As an aid (if needed) here's the signal flow path from the gram socket in the schematic through the switch contacts (numbers given) when the gram function is selected: Socket III >> switch contacts 64--65>>switch contacts 49--50>>switch contacts 18--17. Lawrence.