[TenTec] 9420 VS Switcher

[John W. Farler]

Gary, My Hercules II blew one section of the 9420 or the supply in losing one section blew the control section of the amp.  TT repaired the amp, but I didn't want to try to get the supply down there for repair.

As a result, I bought an Ameritron 75 Amp switcher, and have used it for three or more years with no problems at all.  It's the same as the MFJ Supply with a different tag on it.
It puts out the 500 watts with no problem.I

John, K4AVX

Original MESSAGE:
Date: Sun, 2 Jun 2019 04:50:27 -0400
From: Gary Hendricks
Subject: [TenTec] 9420 VS Switcher


I have been looking at the schematic for my 9420 supply and it looks 
like the output of the series regulators have no over voltage 
protection. If my memory doesnt fail me I think when I was working at 
TenTec I remember hearing the service guys talk about pass transistor 
failures on this supply being somewhat common.

Has anyone used one of the high current switching supplies on the 
Hercules II amp? I see some avail at 14 volts and 100 amps with every 
protection built in.

Thinking about letting 9420 go and using one of the switchers because of 
the protection built in

Thanks

Gary K4MT