[TenTec] Paragon II intermittent transmit

[Ken Brown]

My Paragon II has had an intermittent fault causing no TX power output 
in CW or SSB modes. There was always power in FM mode, and in AM mode 
carrier but no sideband power. These symptoms led me to suspect problems 
in the balanced modulator. FM and AM carriers follow a separate path, 
not through the balanced modulator. I opened up the top cover of the rig 
today, and did some probing with the oscilloscope. Before I got very far 
it started working again. The manual "sort of" explains the operation of 
the balanced modulator without being specific about voltages. I have 
been monitoring the TD line into the balance modulator, because 
according to the manual the balanced modulator is enabled by this "TD" 
voltage. The manual does not say what the correct voltage is. I am 
getting about 2.7 VDC here when the rig is keyed. This voltage comes 
from the CONTROL BOARD, and is switched on by Q7 , which is sourced from 
the +REG supply.

I would like to know what the correct voltage during key down is on TD 
line. Anyone poked around in this part of a Paragon II?

DE N6KB