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

Davewantsone · 13th Jul 2019, 10:04 am

I have repaired quite a few RT1 and R200 radios.
What I use to assist in faultfinding is I have working RT1 with a 0.1nF capacitor connected at one end to the collector of TR3. With RT1 tuned to a radio station I connect a fly lead to this capacitor and use it as a signal source to inject 470 kHz signal into faulty RT1 or R200,300 etc. In some cases it may be necessary to connect the ground of both receivers together. It then becomes easy to trace the fault through the IF strip connecting the fly lead to the bases of the IF transistors. It is also good for alignment of the IF strip. Once the fault has been found the repaired radio will pick up the IF signal from the RT1 with just a loop around the ferrite rod aerial. Lengthen the fly lead distance to attenuate the signal. The RT1 IF had been checked for accuracy.

13th Jul 2019, 10:04 am	#7
Davewantsone Hexode Join Date: Dec 2011 Location: Wigan, Greater Manchester, UK. Posts: 291	Re: Roberts R200 radio not functioning. I have repaired quite a few RT1 and R200 radios. What I use to assist in faultfinding is I have working RT1 with a 0.1nF capacitor connected at one end to the collector of TR3. With RT1 tuned to a radio station I connect a fly lead to this capacitor and use it as a signal source to inject 470 kHz signal into faulty RT1 or R200,300 etc. In some cases it may be necessary to connect the ground of both receivers together. It then becomes easy to trace the fault through the IF strip connecting the fly lead to the bases of the IF transistors. It is also good for alignment of the IF strip. Once the fault has been found the repaired radio will pick up the IF signal from the RT1 with just a loop around the ferrite rod aerial. Lengthen the fly lead distance to attenuate the signal. The RT1 IF had been checked for accuracy.