[Amps] Amps Digest, Vol 93, Issue 11

[Bill, W6WRT]

ORIGINAL MESSAGE:

On Fri, 10 Sep 2010 13:45:38 +0200, Marius Hauki
<rezycle.bin at gmail.com> wrote:

>If the back to
>back diode combination should become open circuit (in case of a very
>large glitch) and someone (not me) then removes Bminus before Bplus,
>there is no return current via the chassis path to Bminus. This would
>place the RF deck at Bpluss.

REPLY:

Correct, however in my experience diodes in normal operation always
fail in the shorted mode rather than open. A truly large glitch such
as a lightning strike might cause them to open of course, so I also
recommend a heavy gauge ground wire be connected between the amp
chassis  and PS chassis. This wire is a good idea regardless of what
other protective citcuits are used. 

You could make this ground wire a part of the power-on circuit so that
AC power can not be applied to the PS unless the ground wire is
intact.  

Bill, W6WRT