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Apple Power Supply Questions

C

capknight

New Member
Joined
Mar 19, 2009
Messages
4
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.

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
 
HOLY COOKED ICS BATMAN!

+5.42 will cook 5v logic.

The +5.28 may cook things too.

The power spec for digital logic (TTL, NMOS, etc...) is +5v +/- 5% which comes to 4.75 to 5.25 volts.

You need to check parts in the regulator section to see if any other caps (tantalum) or resistors have changed values.

Also, are you testing these with a load on them? If not, you run the risk of frying the switching power supplies. They tend to blow up if running unloaded on the +5v outputs.

RJ
 
Hello!

Eek! I did test them without loads. Very briefly they were powered on, but thanks for the warning. I'll avoid it in the future.

I'll have a look and see if I can dial down the +5 using the pot on the board as well as looking about to see if anything else bit the dust.

Thanks again for the excellent suggestions!

Best,

C
 
capknight said:
Hello!

Eek! I did test them without loads. Very briefly they were powered on, but thanks for the warning. I'll avoid it in the future.

I'll have a look and see if I can dial down the +5 using the pot on the board as well as looking about to see if anything else bit the dust.

Thanks again for the excellent suggestions!

Best,

C
Click to expand...

Hi, The original PSU was designed to crow bar, off load. There is a zener trip circuit on the +12v. It may be an idea to check this out as well as setting up the other outputs.
good luck
 
When (not if) you get the Vulcans working , with the assistance of the eggheads here (not including myself, I'm dumb as a stick), will they be available? Any advance price-range in mind?

--T
 
Hello,

Haha! I hadn't thought of selling any of them. If I do make them behave themselves and want to part with one, I'll let you know.

Thanks!

ATF
 
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