Precision fidelity C7 preamp

 Is anyone able to refurbish this? What would be good replacement tubes? They now  have  Sylvanias in the phono section( I replaced GE's).
The C7 does not have a high-level stage. It is phono-only! The volume control and source selector function passively with no gain for high-level sources (tuner, CD player, tape deck ...). I preferred using my C7 strictly as a phono stage into the high-level inputs of the various SS preamps I bought and sold over time.
Audio Classics in Vestal, NY is my recommendation for repairs and restoration of HiFi gear. But if your C7 is working and sounding fine I would be content to leave it alone. Just do some tube rolling! 
sad news: The unit is now non- functional . I powered it up and instead of a tube blowing, sharp static like  pops are now emitted from the circuit board(like a light bulb blowing up). There also is a strange glow under the circuit board. The music still plays in stereo!
I ran the unit flat out and controlled the volume from the powered speakers. I had a deep soundstage but i dealt with some tube noise.

Fix it? ..Replace it with a Bellari?; I fi?, Schitt?..some other unit?
Sell It as is ?