If you would like to add a power connector to your MyIDE+Flash these instructions may help.
Please do not try to power a hard disk from your cartridge port, you will probably damage the cartridge, computer or power supply. Using a CF adapter with a CF card or micro-drive will work fine.
A molex power connector cut off an old PC power supply is ideal.
If there is a yellow/black pair, remove those wires.
Opening the cartridge.
The cartridge may be difficult to open the first time as the shells are tightly press fit together.
To start, grab the cartridge at the open end and try to seperate the two halves. If you cannot open it manually, you can very carefully insert a small flat head screwdriver between the PCB and top shell as shown below.
Be careful to insert it only between the top shell and PCB to avoid damaging components which are on the other side of the PCB.
Insert it at the position shown just until you reach the securing peg, then gently pry to release the peg from its holder.
Repeat on the other side of the cartridge. The photo below shows the screwdriver inserted just up to the securing peg, do not insert beyond this point or traces and components could be damaged.
Once you have the cartridge open, locate the position labelled 'C2' on the upper left of the PCB.
Solder your red wire to the hole marked (+) and your black wire to the other hole in the same circle.
Tuck the wires around the side of the pcb so they can leave through the open space behind the IDE connector. This is a tight area, so it will also act as a strain relief for your power wires.
Reassemble the cartridge shell. You now have a standard 5v+ connector you can use to power small devices like a CF->IDE adapter.