50Hz vs. 60Hz

[Tony Duell]

> 4. The big 'gotcha' appears to be ferroresonant PSUs. I knew those would be=
>  a problem=2C but I must admit I didn't know DEC used them. OK=2C so we've =
> been told the RX01/02 is ferroresonant. Think carefully folks - are there a=

The RX01/02 is _certainly_ a ferroresonant PSU.

> ny other DEC PSUs that use ferroresonant transformers? I'm thinking mostly =
> about logic PSUs from early pdp-8/12/15 to later 11s - 11/34=2C 11/73=2C pd=
> p-8a etc=2C but any data on peripherals which used ferroresonants would als=
> o be welcome!

The PDP8/e and PDP8/a do not use ferroresonat PSUs (I have both machines...)
Nor does the 11/40, 11/45, 11/34 or any Q-bus 11 AFAIK. 
I can check the '12 prints if you are not sure.

The safest thing to do is to look at the prints and the mains 
transformer. A ferroresonant PSU will have a capacitor connected to a 
winding on the transofrmer iwth nothing else connected to it. If you see 
that, take care.

DEC used Diabloe Model 30 drives at one point (RK02, RK03). And at least 
one DIablo PSU for said drives was a ferroresonant one. I don't think DEC 
ever used that PSU, though, they used one of their own design with a 
conventional mains trasnsoformer and electronic regulators (so no 
prolems). Actually, IIRC the Dailo ferroresonant PSU was one of the few 
I've seen with taps on the resonant winding so it could be strapped for 
50 or 60Hz.

-tony