Maxtrac Power Control

[John G]

Several of you folks have mentioned that when the Maxtrac is taken out of its normal operating frequency range, it becomes difficult if not impossible to control the output power by means of the softpot through RSS control. It has been suggested and, I understand tried, to just hook an adjustable regulator to the controlled B+ line. Another way that will retain the over current protection already there is as follows: On the logic board, remove R810, 811. Connect a 10K pot from pin 1 of J7 to ground. From the wiper of the pot, connect a 27K resistor to pin 3 of U451. This merely replaces the analog voltage output by the D/A convertor with a user settable voltage. The voltage is taken from pin 1 of J7 because that is tx 9.6 v. That will cut the voltage to the brick off during receive. The manual indicates that the D/A convertor puts out 0 volts in receive and 4 to 7 in transmit.

[COSMOS_]

John.... Does this apply to the 30 watt units ? I have a D37MWA5gb7ak
that I can only get 15 watts out of , even with the Mod. Thanks...

[John G]

Can't guarantee it, but it should be the same. Best I remember, the 30watt is just the 12 watt with an extra transistor to boost the output from 12 to 30 watts.