Ameritron AL80B Amplifier Mod
      By Mitch Cox ( W4COX )
This is just a heads up to those of you who own the Ameritron AL80-B amplifier. Notice the red arrow, this is where a failure will happen sooner or later. The solder lug is placed too close to the ground foil on the circuit board. The solder lug at the arrow is the RF out from the relay that goes under the circuit board and comes back up through the small toroid that connects to the out going SO-239. The lug that causes the failure is about 0.40" from the ground foil, as soon as enough dust gathers around the solder flux around this connection you will hear a big bang. This takes out all of the components that measure RF output and reflected power on the front meter, it also ruins the T/R relay by welding the contacts together.
The fix for this is the cut the large un-insulated wire that runs through the toroid on the bottom of the circuit board, stand the toroid up vertically and support it with either a dab of hot glue or non-corrosive RTV. Re-connect the wire from the relay to the large un-insulated wire where you cut it loose on the back of the toroid. This removes the outgoing RF off of the circuit board altogether and prevents this from ever happening again. If you don't address this problem now it WILL happen to your amplifier sooner or later.
Best Regards,
Mitch
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AL-80B Dynamic Bias Defeat