[TenTec] Centurion 422 Fuses blowing

[W. Keith Hibbert]

BTW: The QRO rig years ago was a homebrew VHF AM station, 4-250 final on 
6, 4X150A on 2, BIG modulator with P/P 812's... NOT QRP by any stretch 
of the imagination!

73, Keith, WB2VUO


On 01/30/2014 08:35, Bry Carling wrote:
> I havea nice Tentec Centurion 422 and the main 20A fuses blowing.
>
> It started spontaneously.
>
> I can turn on the main power OK and the filaments light up on the 3-500Zs.
> The 12 volt power supply is OK because the pilot lights come on.
> However when I flip the standby - operate switch to the Operate positionm the fuse or fuses
> will blow.
> I replaced them with good 250V 20A cuses.
>
> I checked the plate transformer windings and everything seems normal for all three windings.
> Nothing is shorted. The safety ground for the cover-ofrf condition is not across the HV plate
> supply. I checked that nothing else is shorting out the plate supply either.
>
> Does anyone have any idea what might be going on here?
>
> Many thanks - Brian Carling, AF4K
>