[TenTec] Ten-Tec amplifier vacuum relay noise

[Ken Brown]

Arthur Trampler wrote:
> I haven't tried this but want to "compare" noises: recently purchased a 
> Centurion and the relay seems to buzz a bit as it switches...I too am 
> wondering if it is how it is mounted mechanically.  It is free to move a bit 
> and perhaps I set it in the wrong spot!
>
>   
I don't notice any buzz either while it is switching or while it is held 
in the energized position. I just hear the clickity clack as I send. The 
problem goes away when I wear full ear covering headphones.

If you hear a buzz, you may want to check the filter capacitors in the 
low voltage DC power supply for the control circuitry in the amplifier. 
Scope the voltage across the filter capacitor to see if there is a 
significant 60 or 120 Hz ( I don't have a schematic for a Centurion, so 
don't know whether that power supply uses full wave of half wave 
rectification) ripple component there. Or if you don't have a scope, 
just temporarily parallel a capacitor of similar value, across the 
filter capacitor. If the buzz goes away, then the normal filter 
capacitor is probably ready to be replaced.

DE N6KB