[Boatanchors] AF-67 22.5 Volt Battery Replacement

[msix at nmia.com]

> Does anyone know where I could find info on a circuit to replace the 22.5 volt battery in the AF-67?
> These batteries are getting expensive.....thanks...Bill K4JYS
>
2 choices:
Rectify the 12VAC using a negative voltage doubler and apply about 3ma to
a 22V/1W zener thru a dropping resistor. This won't work if you run the
fils on 12VDC :-)
or...
I changed the 5881s to zero-bias Class B 6AG7s and the 12AU7 to a 6CX8
triode AF amp and pentode driver. I think the circuit is still on the
N9BOR pages at
www.qsl.net/n9bor/Multi-Elmac.htm
search for my call there...
73 John W7ZFB - always good in QRZ