[Amps] GE EF-5A VHF Amplifier

[Xmitters@aol.com]

Hello Again :-)

I have a General Electric EF-5A VHF power amplifier. I think it is Progress 
Line or Mastr Progress Line vintage, not sure.

Every one of these amplifiers I have seen at hamfests a few years ago, all 
had the plate current meter blown open. And with mine, I found out why. As you 
get close to tuning the thing up, you get a big nasty high voltage bang from 
inside the unit, the windings on the RF coke on the plate lead get squashed into 
the center of the RF choke form and quite often, the 4CX250B tube gets 
damaged. I was very careful to properly neutralize the amplifier and careful not to 
overdrive the thing. I got to the point where it appeared stable for 10 
consecutive keyups. OK, I fixed it, so I thought. On the next keyup, she arced over 
again! I had a simpson panel meter in use to watch the plate current, and that 
meter just like all the others, blew open.

So are there any old timers in the group that has some flying time with this 
amplifier that might know how to calm this thing down? Maybe some 
strategically placed Zsorb blocks inside the plate cavity? The amp has been in my shack 
collecting dust, for about ten years because of this issue.

This really looks like a good amplifier and I have a good supply of 4CX250B 
pullouts, so I would sure like to fix this amplifier if at all practical to do 
so.

And BTW if there are any boat anchor collectors out there that would like to 
have some GE Progress Line gear, we really need to get together :-) Swap gear 
for intellectual property maybe? :-D

Jeff Glass, BSEE CSRE
WB9ETG since 1970