[Amps] Alpha 87A Question

[David Kirkby]

jon s wrote:
> I am relaying this for my Father (AI9U) who does not subscribe
>  
> Last night he was back at his station after a 10 day period of non-use
>  
> FT920/Alpha 87A/3 ele Steppir/40_80 Dipole
>  
> With the Amplifier Off - but still in line he was using the tuner to match the dipole, when an "incredible bang" (his words) occured in the amplifier,  tripping the 220V breaker. Upon reseting the breaker, the Alpha powered up but would not do much else
>  
> Anyone ever have something like this happen? 
>  
> I'm wondering how in the world it could have happened with the power switch Off. 
>  
> Anyone care to speculate on a cause?

Parasitic oscillation!! They get blamed for everything on here, but 
perhaps even they are not that troublesome.

Is sounds like something has probably shorted the incoming mains supply 
to me. I suspect a look will soon find the marks of something having let 
the magic smoke out.
-- 
David Kirkby,
G8WRB

Please check out http://www.g8wrb.org/
of if you live in Essex http://www.southminster-branch-line.org.uk/