[R-390] T603 transformer

[Jacques Fortin]

Hi Don,

May I made you remark that the line audio output transformer is always "partly" loaded by the output attenuator at all times ?
Even if a 600 or 560 ohms resistor is not fitted to the line output, the load seen by the output transformer secondary will be 650 ohms instead of 600.
No big deal, right ?
IMHO, if one of these transformers primary fails open, the root cause should be searched elsewhere than the non-loading of the line output.

73, Jacques, VE2JFE in Montreal

Hello Kevin, over the years I have replaced many of these output transformers, especially in the line audio circuit. Most of us use the local audio for our speaker and the line audio is usually open. With the volume of the line audio up there is no load on that output transformer. To combat this, I put a 600 ohm resistor across the line output on the back of the radio. This gives the line audio a load and saves the transformer.  (The resistor is actually 560 ohms 2W)

Hope this helps, happy new year!
Don WC4G