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Re: Apple Power Supply Questions
On Apr 13, 3:44 am, "Michael J. Mahon" <mjma...@aol.com> wrote:
> capknight wrote:
> > On Apr 12, 7:39 pm, capknight <cepheusfi...@gmail.com> wrote:
> >> Hello,
>
> >> I picked up a number of active and dead power supplies recently. A few
> >> are the AE Vulcan GS supplies, AE IIe Supplies and original OEM Apple
> >> supplies.
>
> >> Some were dead but I was able to resurrect them by replacing the
> >> electrolytic capacitors.
>
> Yes, I have a couple of supplies to do the same surgery on. ;-)
>
> >> The readings are a bit odd on the Vulcan GS supplies. I've listed them
> >> below with modified and unmodified numbers (meaning I replaced the
> >> caps in one and left the other original).
>
> >> The negative 12 volt leg seems really low on the Vulcan GS supplies as
> >> well as the re-capped AE IIe supply.
>
> Since I presume these are unloaded voltages, they are solely the result
> of inaccuracies in the windings of the high frequency transformer.
>
> The voltages you report are all within tolerances for the uses that
> the supplies are intended for.
>
> >> I did not test the Vulcan GS supplies with the 105mb hard drives
> >> installed. I was able to find re-certified drives that work just fine
> >> with the Vulcan GS cards.
>
> I'm curious about which drives you found that work...
>
> >> Testing was done straight from the boards and not through the cables.
>
> >> One thing I did note on the Vulcan GS supplies is that the gauge of
> >> the wires from the 120v receptacle to the switch and board are very
> >> thin in comparison with the other supplies.
>
> >> Any thoughts?
>
> That shouldn't make any difference. The total power drawn by the supply
> is well under 100W, so the line current is under 1 ampere. Any slight
> voltage drop in the line section is regulated out by the supply.
>
>
>
> >> Thanks!
>
> >> C
>
> >> Modified Vulcan GS (caps replaced):
> >> ================
>
> >> -4.32
> >> -10.07
> >> +12.19
> >> +5.47
>
> >> Fan: +12.17
>
> >> Molex for HD: (red) +5.46
> >> (yellow) +12.17
>
> >> Unmodified Vulcan GS:
> >> ==================
>
> >> -4.27
> >> -10.05
> >> +12.13
> >> +5.42
>
> >> Fan: +12.11
>
> >> Molex for HD: (red) +5.47
> >> (yellow) +12.08
>
> >> Modified Applied Engineering IIe Supply (caps replaced):
> >> ============================================
>
> >> -4.99
> >> -11.6
> >> +12.03
> >> +5.28
>
> >> Unmodified Apple IIgs Supply:
> >> =======================
>
> >> -4.98
> >> -12.13
> >> +11.24
> >> +5.05
>
> > I forgot to note that I did make some slight adjustments to the pot on
> > the board to see if I could move the voltages around a bit. It helped
> > on the AE IIe supply.
>
> > Thanks,
>
> The only actively regulated output is the +5v--all the other voltages
> are supposed to track that voltage open loop, just by virtue of the
> transformer winding ratios. The adjustment is for the +5.
>
> Standard Vcc tolerance for TTL is 5v +/- 10%, so anything from 4.5v
> to 5.5v is within spec (though timing margins will vary somewhat
> over that range, the parts should continue to meet spec).
>
> The other voltages are less critical, particularly the negative
> voltages.
>
> -michael
>
> ******** Note new website URL ********
>
> NadaNet and AppleCrate II for Apple II parallel computing!
> Home page: http://home.comcast.net/~mjmahon/
>
> "The wastebasket is our most important design
> tool--and it's seriously underused."
Thanks for the reply!
Perhaps I should also try the supplies under load. I was mostly
concerned by the odd readings in the Vulcan GS supplies on the
negative voltages.
I have much to learn about these things. At the moment I was just
comparing the existing caps in the supplies, matching them as close as
possible on Digikey and installing. It's actually worked out pretty
well so far!
The Vulcan GS drives that I found in the 105mb range were the Conner
CP3104. Discount Computer Peripherals has a few in stock. They are
located at http://www.4drives.com/. Someone was kind enough to point
me
to an FAQ or file that listed the exact drive types for the Vulcan
series.
I was able to get the drives up and formatted using the AE tools on
the 3.5" disk provided. Afterwards with some fiddling I was able to
get the Microdrive Turbo GS CF card working in slot 7 with the Vulcan
GS card in slot 4 (?).
Copied the files over in GS/OS and it works great! A bit slow compared
to the CF card, but it was very cool to get them working.
Henry over at Reactivemicro dug up a IIe ROM for the Vulcan card so I
can put one of them in my IIe. I need to do some research to make sure
the Vulcan GS and IIE card were the same except for the bios (crossing
fingers).
I have/had a third Vulcan GS card and supply, but I made a boo boo on
the supply and it was quite the spark. The card is misbehaving from a
different mishap.
Two functional and one down. Ack.
Anyhow thanks again for all the info!
Best,
C