Apple Power Supply Questions

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.

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.

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.

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?

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,

C

Yes, I have a couple of supplies to do the same surgery on. ;-)

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'm curious about which drives you found that work...

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.

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

Could you point us to that info please? :) It'd be good to know what I
can replace my 40Mb IIe drive with when it fails.

Do you know what version that IIe ROM is? Mine is v1.4 either E or F
(it's hard to know for sure because the printing ran off the bottom of
the sticker) so I was just seeing if there's a newer version.

Thanks!

]3ob

> > located athttp://www.4drives.com/. Someone was kind enough to

Hey! I thought the Vulcan was an ST506 interface. But the CP3104 is an
IDE (ATA) drive.

So I am guessing from your message that the Vulcan's requirement is
for an IDE drive that supports 8-bit transfer mode (which was deleted
from practically all drives - the last vendor I know of to support it
was Conner Peripherals in fact).

FYI, it is a requirement of the CompactFlash specification that all CF
cards must support 8-bit mode. So you should be able to drop in any
size of CF card by using a simple passive adapter like this one:
<http://www.dealextreme.com/details.dx/sku.10309> ($2.64 with free
shipping) or this one that has an externally accessible CF slot
<http://www.dealextreme.com/details.dx/sku.10311> ($4.21 with free
shipping).

The negative supplies are used by only a few circuits, and only
for bias, with very low currents. I'd expect everything to work
fine with a 20% voltage tolerance. The only exception would be
circuits that were marginal to begin with, but again, I don't
expect any problems.

The loads I use are 25W wirewound resistors. I use a 5 ohm load
for +5 (1 ampere) and a 10 ohm load for the +12 (1.2 amperes).
This is actually a "disk busy" load, so it gives a good indication
of the supply's performance.

Negative voltages don't require loads, since only a few milliamperes
are drawn from them in use.

Great! You might also want to compare Jameco for prices.

<snip>

That's correct.

The current surge may have only blown the fuse. The supply may be
otherwise undamaged assuming that the short has been removed.

Unless the power transistor is blown, it shouldn't be too hard to
fix. The problem with switching supplies, apart from the fact that
they are dangerous to probe while operating, is that they are
regulated by a feedback loop. Anything amiss in the loop can cause
misbehavior (like shutdowns), so there are more components to rule
out than if the feedback loop were not there.

One way to simplify diagnosis of a feedback system is to break the
loop, so all "signal" flows are one-way, but many systems are unstable
with the feedback disabled, including most switching supplies.

You're welcome, and good luck!

Hello!

I haven't received it yet, but as soon as I get it I'll let ya know!

Ok I hope this chart comes out..

---------------------------------------------------------------------------
---------------------------------------------------------------------------

Drives used in the 20 meg Vulcan:

+PHYSICAL+ LOG.
PAGE
144
MANUFACTURER UNFORMAT WTH. PL CYLS ST CYLS INTERFACE ACC
XFER. POWER
MODEL NUMBER FORMATED HGT. HD PREC AC HDS REC.METH T-T
CACHE MTBF
L.Z. ST ADDITIONAL
COMMENTS

---------------------------------------------------------------------------
SEAGATE 25.0MB 3.50 2 404 26 615 IDE(AT) 40ms
7.5Mb 9.0W
ST125A-0 21.5MB HALF 4 NONE SM 4 (2,7)RLL 8.0ms
150K
AUTO 17

---------------------------------------------------------------------------
SEAGATE 25.0MB 3.50 2 404 26 615 IDE(AT) 28ms
7.5Mb 9.0W
ST125A-1 21.5MB HALF 4 NONE SM 4 (2,7)RLL 8.0ms 150K
(in mine) AUTO 17

---------------------------------------------------------------------------

Drives used in the 40 meg Vulcan:

+PHYSICAL+ LOG.
PAGE
144
MANUFACTURER UNFORMAT WTH. PL CYLS ST CYLS INTERFACE ACC
XFER. POWER
MODEL NUMBER FORMATED HGT. HD PREC AC HDS REC.METH T-T
CACHE MTBF
L.Z. ST ADDITIONAL
COMMENTS

---------------------------------------------------------------------------
WESTERN DIGITAL 48.0MB 3.50 2 782 27 977 IDE(AT) 70ms
7.8Mb 7.0W
WD93048-A 40.0MB HALF 4 SM 5 (2,7)RLL 4.5ms 30K
17 1:1
INTERLEAVE

---------------------------------------------------------------------------
WESTERN DIGITAL 48.0MB 3.50 2 782 27 977 IDE(AT) 69ms
7.8Mb 6.9W
WD93048-AD 43.2MB HALF 4 SM 5 (2,7)RLL 40K
(My original) 17 56 BIT ECC, 3:1
INTERLEAVE

---------------------------------------------------------------------------
WESTERN DIGITAL 48.0MB 3.50 2 782 27 977 IDE(AT) 28ms
7.8Mb 6.9W
WD93044-A 43.2MB HALF 4 SM 5 (2,7)RLL 4.0ms
8KB 40K
(Tried, works) 17 56 BIT ECC,
3,329 RPM

---------------------------------------------------------------------------
CONNER 3.50 2 788 26
CP-341 42.9MB HALF 4 NONE VC (2,7)RLL Works in
Vulcan
AUTO COMPAQ
OEM, TYPE 17

---------------------------------------------------------------------------
CONNER 3.50 2 805 26 IDE(AT) 29ms
7.5Mb
CP-342 42.9MB HALF 4 NONE VC (2,7)RLL Works in
Vulcan

AUTO

---------------------------------------------------------------------------
MINISCRIBE 51.3MB 3.50 2 745 28 IDE(AT) 28ms
8.0Mb 8.0W
MS8051A 42.7MB HALF 4 NONE VC (2,7)RLL 8.0ms
32KB 150K
AUTO
3,484 RPM

---------------------------------------------------------------------------
MAXTOR COLORADO 51.3MB 3.50 2 745 28 IDE(AT) 28ms
8.0Mb 8.0W
8051A 42.7MB HALF 4 VC (2,7)RLL 8.0ms
32KB 150K
AUTO
3,484 RPM

Vulcan Gold can use:
Conner CP30084 80meg 1/3 height C/H/S: 903/4/46

Conner CP3104 100meg 1/2 height C/H/S: 1547/4/33

---------------------------------------------------------------------------
---------------------------------------------------------------------------

Hope that works for you!

C

Interesting.

I think the biggest problem with the Vulcan cards is that they are
programmed for a very small segment of hard drives. I've tried other
40 and 100 megabyte drives from the period and haven't had any luck.

If it's not on that list above, they simply don't work.

Thanks for the info on the CF adapters!

C

Sweet! Any additional info is much appreciated.

Definitely will check them out too!

So the cards are the same and the bios is just different? Exciting!

I think I nuked the power transistor. The Vulcan has those somewhat
"interesting" heat sink attachments to press the transistors against
the wall of the supply to conduct their heat. The piece of aluminum
holding that particular transistor (I am guess that's the one right
next
to the fuse assembly) is a bit tarnished. When I replaced the fuse and
tried again, the spark comes right out of the area.

Ack.

I think it has to do with the ceramic caps I replaced. The two ceramic
caps that look like little boxes. Think I read the readings
incorrectly
and installed incorrect replacements. Oops.

Somehow I lost the two originals as well (ack).

Need to figure out what to replace now.

Keep me busy this weekend! In between blowing power supplies and
running all my cases through a bath of retr0bright! Hah!

Thanks again!

C