[TenTec] Herc II and 9420 problem

[Harry Coates]

Tom,

I had problems like that also for along time, usually happened when I apporched 200+ watts output.. Ended up replacing pass transistors in 1 9420 ps unit.. Than found a bad solder joint on one of the big shunt resistors on the power dist board.. Start at the power connector and work to the amp boards checking voltages at each one.. Do a little tug and wiggle on "EVERY" component lead you can get at.. If it moves look again..  I ended up replaceing all 8 power transistors and found 5 more bad solder joints..

The HERC II is worth anything it takes to fix.. 

GL,

Harry Coates
WA8HC1 at charter.net