Jay wrote:
  Ok, is there a known severe RFI problem with mounting
a RX02
 directly on top of a RL02 in an H960??? 
Forgive the delay in writing about this.  I had the EXACT same problem
with RXO2 mounted on top of an RL02 drive on y PDP 11/34A. At the time,
my suspicion was that the gigantic transformer in the power supply of
the RX02 was generating some kind of magnetic field tha was disturbing
the RL02.  I mounted the RX02 underneat the RL02, andh never had any
problems since.
Rick Bensene
The Old Calculaor Web Museum
http://oldcalculatormuseum.com