[R-390] R-392

[Jacques Fortin]

Hello Les,

I have some comments about the R-390/URR...
I agree that the 47 ohms resistors fitted on the cathodes of the 6082 pass tubes surely needs to be changed.
5W parts can be used there.
But, IMHO, the same value resistors fitted on the cathodes of the rectifier tubes need to be replaced too.
For the rest of the parts within, all depend on the conditions that the R-390 unit was used and stored.
I found many of the Allen-Bradley carbon film resistors in mine that were completely off tolerance and I had to replace those, especially the 2.2k ohms that feed the plates of the IF amplifier stages.
I also agree that most of the capacitors used within cause no problems, being Sprague Vitamin-Q types.
Except if you find some with traces of oil on their ends: that means that the gas-tight seal have failed and the internal "oil" has been contaminated with oxygen, which result in the well-known PIO "leakage" syndrome.
I had to replace some in my unit (1st contract Collins, sn 2074) but no more than 4 or 5, all in the IF module.
And yes, fitting a solid state HV regulator in is a good idea !

73, Jacques, VE2JFE in Montreal

The only "problems" connected to the R-390/URR are the 47 Ohm resistors under the chassis, four of them if my memory is right.
They are usually slightly charred from heat... 
There is a solid state  kit available that reduces the heat from the PS. Google it. 
No problem caps. Remember this
wasn't a cost reduced receiver like the R-390A. 
Les
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