[Milsurplus] "Sick" R390/URR

[Unserviceable but Repairable]

Ya know the 390s only make a modicum of audio out fm their 6AK6 output
stage.  RX's 500Z output to a match xfrmr then a common low-sensitivity
hi-fi/stereo spkr might be a contributor.

Dead bands often fm oxidized xtal pins in that cannister on top.  I go at
'em w. a brass Ace Hdw. toothbrush.  Saves lotsa contact cleaner & does
much better job ...and eliminates possibility of floating rx off 
bench while swimming in contact cleaner pool.

  'rm