This very rough video shows the bad effects of improper neutralization in an AL811H Ameritron amplifier. Poor neutralization will cause significant SWR error on 15 and 10 meters as the Plate control is moved through resonance.
Hi Tom, quick question, I had to replace the tuned input board on the 811h I picked up. Tuned input was fried. The new generation board seems to have a different hookup location for the blue grid wire, which was by the relays, and is now marked to place by the rest of the wires by the transformer side. D16 is fine, loads fine with palser with full output, but I get no or very little grid current, lol, did that make sense? Is it correct that they changed the grid, blue wire that goes straight to the grid meter, from the relay area to the string of wires connected on the right side of the back board, thanks Tom for all your help.
MFJ for some time has been installing a fan that barely moves air. Almost all newer 811s have grossly inadequate cooling. If it has a Cooltron fan, the fan is junk. The protection stuff has been updated in newer amps, any problems like MOVs can be addressed when they fail. Many H models are not properly neutralized, but problems like that can be addressed on an as-needed basis. I need to do a better video on neutralization.
