24 Sep
2009
24 Sep
'09
11:51 a.m.
Thanks to all those who have responded on 50Hz vs. 60Hz
So to summarise:
1. Most PSUs are unlikely to present a problem, especially since we're going from
lower to higher frequency.
2. Tape drives are likely to run just fine.
3. Disk drives will be as expected (pulley issues) for older drives, but RL should work??
4. The big 'gotcha' appears to be ferroresonant PSUs. I knew those would be a
problem, but I must admit I didn't know DEC used them. OK, so we've been told the
RX01/02 is ferroresonant. Think carefully folks - are there any 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, 11/73, pdp-8a etc, but any data on peripherals which
used ferroresonants would also be welcome!
Thanks
Mike
http://www.corestore.org
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24 Sep
24 Sep
12:22 p.m.
On Sep 24, 2009, at 2:51 PM, Mike Ross wrote:
3. Disk drives will be as expected (pulley issues) for
older
drives, but RL should work??
The RL Technical Description document states that the drives must
be switched between the two voltage ranges, but that they operate on
either 50Hz or 60Hz.
-Dave
--
Dave McGuire
Port Charlotte, FL
2:22 p.m.
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
4:45 p.m.
From: "Mike Ross"
4. The big 'gotcha' appears to be
ferroresonant PSUs. I knew those
would be a problem, but I must admit I didn't know DEC used them.
OK, so we've been told the RX01/02 is ferroresonant. Think carefully
folks - are there any 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, 11/73, pdp-8a etc, but any data
on peripherals which used ferroresonants would also be welcome!
I know the 8/i uses a 704 ferroresonant supply, and I'd guess most
PDP-8 cpus of that vintage or earlier. I'm unsure about the 8/L's
718 power supply. (Normally there'd be a 50Hz variant described,
but I don't see one, but I don't have a proper schematic for the
supply, either.) The PDP-12 uses a 724 power supply, which also
has a resonator. The PDP-8/i and PDP-12 seem have a resonating
capacitor supplied with the transformer for the intended configuration,
so it may suffice just to change the wiring or the capacitor. The
8/a used a supply which has a different transformer part number in
the 50Hz version.
Vince
5568
days inactive
5568
days old
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