The AM Forum

Attempting to build my own version of Harvey Wells APS-50 power supply.   Anyone have the specs for the HV transformer?  Near as I can tell from the manual Figure 17, it looks like 470-0-470 at 350mA would do the trick.

Thanks,
Steve KK7UV

I used what I had on hand; 350-0-350 @ 180 mA. FWCT, 1N4007's, and a 8 Hy 100 mA dollar hamfest choke. Forget the output voltage, but it was close enough. Runs cool, it gets somewhere between 20-25 watts carrier out.

Just remember, that thing has DC all over the tank ckt. I wonder why they chose to do it that way? Blocking cap is right at the ant connector.

Phil

I suspect that was the only way they could get it to work on 6 & 2M. I had one mobile in the late 50's and actually worked Eskip with it on 6M but I was mostly on 10/11M and some 20M.

Carl

Carl, since the one I have isn't near collector grade, I thought about removing the vhf coupling coils and the phono jack, and moving the blocking cap just to give it a try. I believe the PA B+ voltage coild be bumped a little bit and maybe a little more outpoot. The stock tank circuitry is the limiting factor at the moment; it's basically an arc-over waiting to happen as it is now with all the low rated components and full DC sitting on them.

Phil