Re: Internal Heavy Duty Power Supply

[Ed Eastman <noone@nowhere.net>]

Mark Frischknecht wrote:
> Dou you have any Diagrams of how you did that or some informative pictures?

On both project I eyeballed everything as I progressed, no diagrams were
made.

The first project was very simple, make hole, insert fan, plug fan into
IIgs MB fan connector.

The second project was little more complex.  Open, remove wire
harnesses, jumper voltage to 115, jumber power wire to ground, attach
IIgs power lead, run AC through switch, modify IIgs PS case into
mounting bracket, mount.  Easy huh?

Hopefully the following descriptions may help you if you'd like to do
the same thing, and ATX PS inside a IIgs.

Well for the first one, I was having some stability issues in my IIgs
and noted how hot the power supply was getting.  Too hot, I was
thinking.  I had a fan from a PC and held it to the top of the IIgs
power supply and went, hmm, should fit.  I disassembled the IIgs PS and
found that near the front were some big heat sink fins and 'lots' of
space.  So I set the fan on the disassembled PS, put the PS back in the
IIgs and tried to close the lid.  There was almost enough room.  So I
cut a hole in the top piece of the power supply, spread the fins on the
heat sink to allow more depth and mounted the fan as low as posisble
above the heat sink fins.  (Don't ever press onteh tops of my IIgs with
this mod, the blades astart to conect with top of the heat sinks.)  Then
I eyeballed where the fan touches the top of the case and removed the
fins from the inside.  This was done neatly with a pair of pliars.
First insert the pliars into the cracks between the plastic fins.  Then
squish the fin to get a good grip near the underside surface, then
twist.  It'll peel the fin right off fairly neatly.  This leaves the top
of the IIgs looking close to  normal.  A little sand paper or grinding
to tidy it up and remove excess bumps and it looks OK.  (By OK, I mean
ugly hacked.)  Keep in mind though that removing these air vent fins
also removes the regidity and strength to hold stuff up on that spot.

So for a picture of what this looks like, let me help you visualize:
pull the main box of your IIgs aside and look at it.  :)  For the
inside, open the IIgs take a fan from a PC and set it on top of the
power supply about an inch back from the front.  (If you don't have a
fan handy, you can draw one on a three and a half inch square piece of
paper for the same effect.)

On the second project, I had been thinking about the buggie power supply
and the fan I had on mine and a really small ATX PS I had seen recently
inside a PC at work.

I found the pin-out of the AXT power supply on on the box (and on the
internet prior).  Make sure your ATX PS comes with -5V if you are going
to try this yourself.  I got a similar pin-out for the IIgs connector
and power supply.

My thought was that he ATX PS board was small enough that it could go
inside the IIgs PS box but it was about a half inch or more too wide.
Other considerations were that I wanted the fan to exhaust and that no
AC voltages were to be accessible inside the IIgs.  Call me greedy, I
wanted enough room to mount a disk inside in the same space too.  (Think
a Vulcan or Pegasus HD/PS combo.)  And don't forget, the IIgs should
look 'stock' when done.

Having tried to mount and twist and tuck a new PS board inside the IIgs
PS case, I finally decided to nibble out the sides along the bottom and
let the darn power board stick out, AC and all.  Even then I ran into
some issues getting the board slide in the way I wanted to mount it and
just removed the sides all together.  Once I did that, I realized that
the original housing was tight on the board and would add negigible size
to the board and would hold the fan in place and keep fingers and stray
wires out of the AC.  I nibbled the container until all I had left was
an L shaped piece of aluminum consisting of the back and bottom plates.
 Voila!  My IIgs PS was now a mounting bracket that snaps into the IIgs.

In summary, I removed the 115/230 switch to make room for the IIgs power
switch and put a IIgs wiring harness on, putting a switch on the AC line
into the PS and finally hard wiring the PS into 'on' mode.  I drilled
holes int he case of  the ATX PS and mounted the ATX case to the IIgs PS
case using the screws formally used to mount the original PS board.
Then I reassebled and sealed the ATX PS with the modifcations.  Hmm,
looking I notices I also removed some tabs from the metal lid shielding,
the lid didn't fit quite right as the original PS left a gap between
itself and the lid.

Pretty strait forward really.

As for pics, I don't have any and I don't know why, I recall taking
some.  I have the second project here and can take some pics.  E-amil me
and I'll send them out.

Thankx,
Ed