Collins R-390 Receiver Break In

[wb1aij]

The break-in feature feature on my R-390 is not working. I have the schematic for the R-390-A but they are different. The R-390 circuit is a bit more complicated involving other switches beside the "break-in" switch. It seems that most hams have the R309-A model. Does anyone know where I can get the schematic for my model? I would like to get that feature operating but I don't want to unlace cables to trace wiring all throughout the receiver and I especially don't want to remove the front panel & have all of the gears get out of sync.
Bob Tomlin
WB1AIJ

[W1EUJ]

Are you going to Google search anything?

[W2XR]

A frequent reason for the break-in relay not functioning in these units is the failure of the selenium rectifier stack. This failure mode is common to both the R-390 and the R-390A. If the stack has failed, replace it with a silicon rectifier. That was the problem with my Motorola R-390. The selenium stack in my '67 EAC R-390A is original and still works fine.

Check to see that you are getting DC to the T/R relay. I don't recall the correct voltage, but I think it is on the order of +28VDC.


73,

Bruce

[N3DRB The Derb]

if he did a google search it would probably take him right back here