[TenTec] Paragon II RS-232 noise, problem solved

[Ken Brown]

I dug a bit deeper into the Paragon II, and the Paragon II Operator's 
Manual. I found that the schematic for the RS-232 board is incomplete. 
Some little details which someone may have thought were non-essential 
were left out, such as the Vcc to the big ACIA chip. There is no ground 
wire included in the cable running from the RS-232 board to the DB-25 
connector board. I thought adding a ground here would fix the problem, 
and maybe it would have, however before it tried that, I noticed the 
single wire used for the CI-V interface. This wire, which runs from 
connector W on the RS-232 board to connector W on the SIDETONE BOARD, 
also does not have a ground wire with it. Unplugging the wire at either 
end eliminated the noise (or at least put it below the noise floor of 
the radio.) I left it disconnected at both ends, as I do not intend to 
use the TTL level CI-V interface.

DE N6KB