Internal p.s.: Transplant How-to-Do-It

[buggie@ben16.unm.edu (stephen e buggie)]

buggie@unm.edu                                  January 23, 1999

         APPLE II INTERNAL POWER SUPPLIES:
    HOW TO TRANSPLANT THE IIE P.S. CIRCUITRY
              INTO THE IIGS CASING

          by  Steve "Power Man" Buggie

       Working IIe internal power supplies are abundant and cheap,
while IIgs power supplies are getting scarcer and scarcer.  I sell
_external_ 150 watt "bugg-power" units for $27 plus $5 shipping;
201 of these units have been shipped since April 1996!

       The IIe and IIgs internal power supplies use exactly the same
output voltages and color codes:  BLACK = negative (two wires);
ORANGE = +5v DC;  YELLOW = +12v DC,  GREEN = -12vDC,  BLUE = -5v DC.
The IIe unit is rated by Apple at about 35 watts and the IIgs unit is
rated by Apple at about 45 watts.  The IIe units were made by Astec,
while the IIgs units were made either by Astec (heavy, steel casing),
or by DynaComp (lightweight brushed alumnum casing.  The Dynacomp
IIgs p.s. is more prone to failure.

       Still, for portability, the internal power supply remains
useful.  I can do the work described below for you at nominal cost:
$12 plus $4 shipping for an outright sale.   $6 plus shipping if you
mail me your dead IIgs power supply.  $2.00 plus shipping if you send
me a GOOD IIE p.s. in addition to the dead IIgs p.s.

       The transplant is easy enough that the ordinary "solder-slinging"
user can do this himself  Here are step-by-step instructions.  These
instructions apply to dead DYNACOMP IIgs power supplies --- I have
done the transplant successfully on two of these units.  The ASTEC
IIgs p.s. has a different mounting arrangement for the circuit board.
I've looked at it, but have not yet done the transplant on the Astec
IIgs version.

TOOLS & MATERIALS NEEDED:  Soldering iron and rosin-core solder;
       wire cutter and wire-stripping tool, philips-head screwdriver;
       electric drill; brown corregated cardboard, adhesive glue (e.g,
       "Liquid Nails" or equivalent non-conductive adhesive), heat-
       shrink insulation for AWG-18 wire: 3/16" diameter prior to
       shrinkage, DC voltmeter.


1.  TEST both power supplies to verify that the IIE unit is GOOD and
that the IIgs unit is BAD.

2. With power cord disconnected, remove the case=screws and open the
two units.

3. Inspect the FUSE in the IIgs unit.  It is soldered to the board :-(
If fuse is blown, replace with a fuse of the same amperage.  Apply power
and check voltages at the Molex-7 nylon plug. If unit works, then close
up the box --- you're done!  If fuse blows again, then proceed to step 4.

4. Cut the colored output wires:  For IIgs unit, cut them NEAR the board;
for IIe unit, cut them near the plug.  This will allow wires of the
finished unit to remain relatively long. AC plug to be DETACHED from the
unit in this and in the remaining steps.

5. IIgs unit: near the AC switch/socket end, notice where the brown (live)
wire and blue (neutral) wire are soldered to the board.  But both wires
close to the board.  Detach the green wire (ground) from its bolt on the
inside casing.

6. IIe unit: Find the brown (live) and blue (neutral) AC wires; cut those
wires, leaving the wires that attach to the circuit board as LONG as
possible.  These wires are located near the switch/socket end of the
unit.

7. IIgs unit: remove the philips-head small screws that hold the
circuit board to the casing, and lift the circuit board out.

8. IIe unit: remove philips-head small screws; lift the circuit board
out.

9. Hold the two circuit boards side by side.  Notice that the IIgs version
is LONGER than the IIe version.  Notice and compare the locations of the
holes for the mounting screws on the two boards.  Near the "switch-socket"
end, both boards have two holes.  Midway down the length, on the
"starboard"
(right side), the mounting holes are slightly misplaced. Using a 3/16"
drill, drill a hole on the IIe circuit board slightly "forward" of the
present hole, so that the bolt will be positioned correctly with its
barrel-nut on the IIgs inside casing.  (The drilled hole will pass through
a non-critical portion of the board.)  Clean away any drill filings.

10. The IIe circuit board will be attached wiith only three bolts inside
the IIgs casing. Check that it will fit correctly by sliding the board
into the IIgs casing.  Redrill the midway-positioned hole if necessary,
removing the board from the casing while doing the drilling.

11. With the circuit board removed, cut to size a piece of brown
corregated cardboard to fit in the "forward" 2/3 length of the casing.
Attach the cardboard to the inside of the casing with "liquid nails"
adhesive --- or other non-conductive adhesive.  The cardboard provides
physical support for the circuit board, and also insulates the underside
contacts against possible short circuits!  Secure the three mounting
screws
through the circuit board: two screws at the "switch-socket" end, and one
screw through the drilled "midway hole.

12.  Connect the AC wires: BLUE to BLUE, and BROWN to BROWN.  Solder them,
clean the solder flux from the solder joiunt, and insulate with
heat-shrink
tubing.  Three layers of heat-shrink tubing are recommended.

13.  At the "bow" (forward end), connect/solder all six output wires,
matching color-codes exactly: BLACK to BLACK,  ORANGE to ORANGE,  YELLOW
to YELLOW, GREEN to GREEN, BLUE to BLUE.  Clean the rosin from the solder
joints, insulated with triple layers of heat-shrink tubing.

14. String the output wires through the side-opening, passing them through
the black plastic strain-relief.

14. (Optional step) Before sealing the unit, non-conductive adhesive
caulking could be smeared on circuit board edges to secure the board from
vibration or movement.  I use 100% silicone caulking in the big tubes:
either "GE SOLICONE II" or "ACE HARDWARE 50-YEAR 100% SILICONE."

15.  Blow out any dust or shavings.  Reattach the cover with its small
bolts.  Before connecting to the computer, attach the AC cord and TEST
THE VOLTAGE OUTPUTS at the Molex-7 plug.  If these are normal, then
the unit can be attached to the IIgs.

16. Salvage reusable parts left over: The switch/  AC socket from the IIe
casing; fuse, resistors, capacitors, etc. from the dead IIgs DynaComp
board.   That's it!                   Steve "Power Man: Buggie

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 ** Stephen Buggie  UNM-Gallup,  200 College Road,      Gallup NM 87301 **
 ** buggie@unm.edu      IIgs/IIc/IIe  voice: (505) 863-2390 or 863-7504 **
 **     GALLUP NM: located just 500 miles S.E. from "Bribetown" Utah    **
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