Russian Tube Preamp, No Return, Here I go again

Are you absolutely certain that you have the right tube in the right socket? Because if you have misplaced the tubes in their sockets, all bets are off, and any symptoms could be explained by that, particularly the ones you mentioned. And no, the power cord is not causing that much in the way of problems. Even if you think you installed each tube correctly, I would open the chassis and take another look at where you placed each tube in relation to the instructions you were evidently given.

yes, tubes are in the correct sockets. I got photo with locations indicated from seller.

Have you double-checked to be sure you got it right?  If so, then I would take the problem to the seller and ask him to reaffirm his instructions to you regarding tube placement.  After that doesn't lead you to a solution,  you need a good tech. 

That's a shame, after all of the waiting.

All is not lost. Broken can always be fixed.