Connecting a 1541-II disk drive to a PC/AT power supply
Written by Sergio Aguayo

First of all, NO WARRANTY! These steps worked for me, but I shall not
be made responsible for any damage that may be caused by this
document.  Of course, this has been reviewed and found OK.

Things you need:

- A 1541-II power supply or a 4-pin male DIN connector
- A PC/AT power supply
- A soldering iron
- A multi-meter if you are not sure what you are doing

Steps:

1. Cut the cable of the 1541-II power supply by the side of the brick.
2. Choose a 4-pin power connector of the PC/AT power supply
3. Connect the BLACK wire of the 1541-II power cable
   to one of the BLACK wires of the PC/AT power supply.
4. Connect the GREEN wire of the 1541-II power cable
   to the RED wire of the PC/AT power supply.
5. Connect the RED wire of the 1541-II power cable
   to the YELLOW wire of the PC/AT power supply.

The thing should look as this
(looking from the back of the PC/AT power connector):

 r   bl  bl  ye 
 e   a   a   ll                 (to the PC/AT power supply)
 d   ck  ck  ow
+--------------+
|OO  OO  OO  OO| <--- PC/AT power connector
+--------------+
 gr  bl  NC  r
 ee  a       e                  (to the 1541-II)
 n   ck      d

If you don't have a multi-meter don't read the following:

- Connect the negative cable to either of the black wires of the AT ps
- Touch the YELLOW wire with the positive cable.  Should read about 12V.
- Touch the RED wire with the positive cable.  Should read about 5V.

Connect the PC/AT power supply as always and turn on your 1541-II.
All should be OK now...

You could remove the 4-pin PC/AT power connector from the cable, but
this is the simplest way of making this modification.  If you want to
do so, just do it.

What to do if you don't have the 1541-II ps's cable
---------------------------------------------------

You'll need, first of all, a pin-out of the power connector:

/----\                  1: +5VDC 1A
|3  2|                  2: Ground
|4  1|                  3: NC (not connected)
\-^^-/                  4: +12VDC 0.5A

Note: The ^^ is the notch side.
[Addendum 7/1/2003: in the figure above, the connector is viewed from
the front side (not the side where the cable is soldered).]

Also, you'll need this extra things:

- A soldering iron
- A 4-pin DIN plug (?)
- A three-wires cable (with at least 1.5m)
- A multi-meter is recommended

Please note: I had the ps cable, so I didn't have to do this.  This
should be correct, though, but who knows...

Steps:

1. Solder each wire to the plug.  If you have four or more wires on
your cable, just cut them.
2. Now you have your power cable!
3. Go to the step 2 of the first part of this document

Notes: 

- The color codes for the wires are for reference only.  I don't know if
  all the power supplies use the same colors.  It is better to use a
  multi-meter and the pin-out above.
- NO WARRANTY

Any questions/comments to sergioag@ec-red.com
5/18/2002