[TenTec] 962 Power Supply Shutdown; RFI Cure?

[Edward A. Feustel]

On 12 meters into a dummy load with a Paragon II, with "NO" swr, at 
about 15 watts output and 3 amps IC
the 962 shuts down after a few seconds of key down. On 10 meters into 
the dummy load, there is no problem.

On 10 meters through a 229 antenna tuner with low SWR at.about 15 watts 
output and 3 amps IC the 962 shuts down.
I am using a balanced antenna and the 600 ohm feedline comes into the shack.

So I believe that I am suffering from RF into Power Supply.  I 
understand that others have had this problem.
I have tried moving the power supply from one side of the rig (right) to 
the other, with no effect and have removed
the common ground with no effect.

Search of the archive says that using ferrite beads on the supply leads 
might help, but does not say what  beads to use or where
to get them. Any other constructive advice would be greatly appreciated.

Ed, N5EI