------------------------------------- Amiga Technologies A1200 Floppy Fix ------------------------------------- By Bruce Abbott (bhabbott@inhb.co.nz) When Amiga Technologies produced the Amaiga 1200 they made a small change to the internal disk drive circuit, so that they could use peecee drives. Unfortunately they did not connect the READY line which is required by some games. To fix the Amiga Technologies A1200 drive all you need to do is solder one wire from the drive onto the motherboard. It will then be 100% compatible with a standard machine. Here's how the mod works:- The AT1200 drive is a Panasonic JU257 designed for a peecee, so it has Diskchange on pin 34 and nothing on pin 2. AT got it to work by joining pin 2 and 34 on the motherboard. Of course this means that the READY signal is missing, which causes the incompatibility. To provide the missing Ready signal, you can solder a wire from the external drive connector at pin 1 (RDY) to the internal RY pad on the drive's circuit board. If you look on the underside of the drive board you should see the words SW1 and RY DC, and a small slot where a switch could go. On the upper side there is an unused pad marked R52 (next to this is R53 which joins the switch in the DC position). Simply connect your wire to this pad. You may need to scrape some paint off the pad to expose the copper track. I will now try to draw a picture to illustrate this.. ____________________________ solder a wire from here.. | ________________ | Panasonic JU-257A605P _ / \ | | | E581 68 ohms \ | floppy disk drive |_| \ |_____________ (should connect \ | ======= |____ to external disk \ | | | | | | drive port pin 1!) \ | | \ | | \_________|_____ R52 R53 | | \O O---O | ..to here | --> O O O | | --------- | | SW1 | o X o | | | --------- | | | | | | | | | --------------------| | | | | | stepper | | motor | | | | | --------------------| The electrical circuit is like so.. External Drive Amiga motherboard Internal Drive -------------- ----------------- -------------- pin 11 Disk Change pin 2 o--------------------+------------------o _CHNG | (nothing) | | .----------- | pin 34 +---------| DC output +------------------o-----+ | | DC | H R53 | | H (DC) | | | | disk drive +-----+ | controller SW1 | | chip R52 | (RY) | pin 1 Ready | | o<------------------------------------------------->+---------| RY output _RDY ^ `----------- | | This is the wire to add! As you can see the modification is really very simple, I wonder why AT didn't do it in the factory?