[R-390] R390(non A) questions

[Edward]

Greetings,

I have always been a fan of the R390A, especially since the mods and restoration tips are well documented (Thank you, Chuck Rippel and others). 

The R390 (non A) is a different story. The only site I have come across is Dave Medley's page (RIP). 

Is there a comprehensive list of mods and restoration tips, along the lines of Chuck's?

Eager to learn more about this receiver, as I am on the verge of getting one. Thanks in advance. 

73,
Ed NI6S