This is a description on how to bolster the power supply for the Mod4


1. Get a second supply, either a 65W or 35W version, be advised
that there are/were two vendors for the supplies for the Mod4.
One was Radio Shack, and the other was ASTEC, either supply will
work. I personally used a 65W ASTEC due to the fact that the Radio
Shack supply has quite a few Technical Bulletins out fixing various
"little" problems with the supply, but generally it works if you
don't push it too close to the 65W limit. If you do you will see
the jiggly screen, and this is due to the supply going into current
limiting mode, it literally starts to cut current to save its fanny
from frying.

2. The next step is to open the cabinet, this is accomplished by removing
the screws from the bottom of the computer, there should be ten screws
when you are done, along with the one right in the middle on the back of
the computer. Then you lift the top up "gently" and lay it to the side of
the computer, it comes off, or rotates off toward the CRT side of the system.

3. Now you need to get a supply of MOLEX connectors that go on the new
supply, corresponding to the power leads you want to run from the new supply.
 I would suggest that you run the Video and Floppy drives from one supply
and the mother board from the other. The easiest way to shop for the
connectors is to take the supply to the electronics store and match it up
there instead of guessing. You will need a two position connector for the
video, a three position connector for the incoming AC, and a 10 position
connector for the floppy drive power.

4. Now you need to remove the keyboard, this is done by removing the screws
you can see around the edge of the keyboard, then gently lifting it up and
out of the way so you can get to the power switch located on the right
underside of the computer. Solder two wires to the same two places on the
switch you see the wires that go to the supply that is already in the computer.
Then thread the wire under the drive housing and put the MOLEX connector on
(The 3 position job) then you are done with the AC part the connector, the AC
is labelled TB1 on the 65W ASTEC and J3 on the 65W Radio Shack supplies.

5. The video part is even easier, since you may be able to get the video
connector to reach the new supply without having to do anything else, be
sure to try to get it to reach before you make a new one. To get it to
reach (Possibly) try uncoiling a turn or two of the video supply line from
the big coil on the iron ring this should be mounted toward the to and on
the inside (Near the CRT) of the mother board, just follow the wires till
you come to it if you are confused as to what this piece is. The video
connector goes on the very right hand side of the big long connector (if
you are holding the supply with the big connector at thr top, the letters
will be upside down) the Video is labelled COM and V2. So after doing this
you are now ready to do the floppy drive connectors.

6. The floppies are just about as easy, just note which of the wires goes
to what to the floppy drives. These are the wires that go up over the top
of the supply and into the back of the floppy drives. Cut each wire then
solder an extension to each of these and put them back into the same slots
in the new MOLEX connector (This will be on the long connector) there will
be three wires going to the floppy drives that you will have to cut and
extend one will go to V1 one to V3 and one to COM.
The connections will be in positions 3, 4, and 9, these numbers
correspond to you looking at the connector as if you help the power
supply with the plug in section at the top and count from left to right.
i.e. position 3 is the third slot/peg from the left side of the power
connection stip, or a COM, V1, and a V3 connection, all you need to make
sure of is that you get the same wire from the old supply to the same
slot on the new supply, wire color doesn't matter.

7. After you have done all the electrical work you are ready to mount the
board. I used 8 nylon stand offs the ones that thread together to form the
legs for the supply. I did this by putting one in each corner hole then
screwing on another one above the board. This left the lower ones with a
threaded hole to allow a screw to fasten in down, I then just lined up two
of the legs with some of the slots in the bottom of the computer and then
bolted it down by putting screws into these stand offs that were over the
slots, you can drill holes to get the other two legs bolted down, but I
doubt you would really need to unless you are going to take the Mod4 on
a bumpy ocean voyage or something similar. Also don't forget to ground the
new supply, you will see on the back of the supply under the corner hole
in the upper left side (you are now looking at the back of the supply with
the connectors at the top) is a grounding pad, just run a wire from the old
supplys ground to this one and you are all done. Plug it all together turn
it on and see if you got all of this right.

8. If you do not feel comfortable doing this modification see if there
is a friend around that tinkers with electronics and is willing to help.
 It really is a fairly simple operation, but if you get wires crossed you
can cause severe damage to your computer, so be careful, and if you are
not sure call someone who knows. The Radio Shack Repair Center nearest
you should be able to give you any extra needed advice, I have always had
no problem with the Repair guys just the salesmen. Good luck!!


**********DISCLAIMER***********

I assume no responsibility for any damage caused to your computer
by doing this modification. You do all modifications at your own risk.
Please feel free to leave me any comments about any information I need to
add to help clarify any part of this modification. I wrote this
assuming the people that are going to try to attempt this have at least
a minor background in using a soldering iron and some simple tools. My
compuserve number is 73327,442.
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