As far as I know, nothing changes in the PA while in reception HAM or GEN.
Maybe you mean in transmision. Then voltage TX13.5V appears (13.5V line is allways present for drivers and finals collectors). After the fac mod, predriver Q01 takes from TX13.5V too. This TX13.5V voltage is reduced for bias to 0.7V in two cascaded regulators. If they are shorted an extreme high bias can pass to the drivers and finals. And some disaster may happen. TX13.5 comes from Q01 in RF unit, via RL01 in RF unit. Check both. They made the Rx/Tx conmutation.
If a tantalum capacitor in Q01 collector shortens and the 13.5V PS protection does not work (mine lowered to 3v), RL01 may have damaged by overcourrent, because Q01 in PA takes power via this relay once the fac mod has been made. In schematic PA Q01 takes from 13.5V line, after mod it takes from TX13.5V via RF unit Q01 and RL01.
But all this is related to Tx/Rx, not with HAM/GEN.
I think the mod was done to avoid PA Q01 to autoscillate in Rx. If you get TX13.5V line with voltage during Rx (RF unit RL01 stuck), the whole PA can oscillate madly.
If it gets hot in HAM Rx... you have a problem somewhere.
