High Density Floppy Controller Manual V1.03


By C.Swinson (c) 2002-2007


STFM REV D Fitting Instructions. Please read the revision note at the bottom of the page before starting!

Here you can see the WD1772 Controller IC. It will need to be unsoldered totally from the ST's motherboard. Much care must be taken not to damage any of the tracks under the IC. Some ST's will have the WD1772 in a socket. In this case the socket must be removed.

The WD1772 now removed. We can now get ready to install the HD Controller Board.
The WD1772 is now plugged into the HD Controller Socket. Notice which way round the IC is in the socket.

On the ST board next to where you took out the WD1772 IC is a connection called "W2" (Top of Picture). Here is where we will gain our Drive 0/1 Select Signal from. De-solder the first joint since there will be a wire attached there.

STE users note that the W2 connection is below the floppy board and called W301.

Here the white wire is soldered into place. There are 3 holes and it must go in the exact oneas shown in the picture (the square hole)

On the bottom of the PCB (underside) there are 2 rows of pins which solder to the ST's motherboard. These pins are seperated by a black spacer. This must be push down towards the bottom of the PCB. If it is hard to push down then cut the black spacer every 2 pins and push the spacer down in sections. Take care when doing this sice bending the pins will cause problems with hole alignment. Its not crytical where the black spacers are, they are more used to keep the pins level than anything. You can remove it if you wish though it helps to keep the pins as straight as possible.

The bottom of the image you can just make out a large IC which is under the controller module. The controller module must be almost resting on top of this IC. If there is any significant space then the module will be too high and no fit under the floppy drive. Make sure your floppy drive still fits on the spacers before you solder in the module!

The HD Controller board is now soldered into place. Make good notice which way round the board is! Then trim leeds.


Now the white wire is soldered to the right solder pin on the HD Controller Board.

The middle solder pin on the board is now soldered to the internal floppy drive's orange wire.

The floppy cable is fitted up-side-down which gives the twist in the cable. HD drives have the cable connections backwards to normal 720K drives.

The now free left-hand pin is for external drives. It it recommended that you fit the external drive socket ( optional ) to prevent confusion at a latter date.

Here is the back off the ST's case. We need to drill a small 6mm hole in the case to allow for the jack socket to be fitted.
Mark out a line from the right side of the Hard Disk connector. Mark down from the top 8mm and draw a cross at that point. It is important to keep the line at 8mm since the socket may get in the way of the case. You may want to look ahead a few pages to see where the socket will be fitted in relation to the case. You can of course mount the socket wherever you wish on the case. If you can find a better location suited to you then put the socket there.
Here a 6mm hole was drilled. A 8mm drillbit was used as a countersink to round the end of the hole a little. Since the ST's case is very thick plastic the hole needs to be countersunk a little.
The socket is now fixed into place. Note from the picture below which way around the socket goes.
The shielding both top and bottom is put back on the ST's motherboard. You can see how the socket just misses the top shielding. Don't worry about the jack socket tab being near the metal shielding. as it is not used. You can cut it off if you wish.

The whole ST board is moved out a little to allow better access to the socket while soldering. A small jumper wire is soldered to the far tag on the socket. The other end is screwed onto the metal shielding. If you have a metal drive shield then leave it off since it will get in the way. This leaves a hole spare for our screw to go in.

Or if you prefer drill a small 2.5mm hole to the left of the screw shown and fix a small 6BA nut and bolt through the case. Then fix the wire to that instead.

The black wire is soldered to the back side of the socket. The other end is connected to the HD Controller board.
The Black wire is connected to the left side pin on the HD Controller Board.

The ST mother board is slotted back into place. The metal shielding. is mounted back into place. The small bolt under the socket you just fitted might get in the way of fitting it back into place. If so just bend the back of the ST's case a little and maneuver the ST back into place.

The floppy cable gets a little tricky because of the fold, so take care and try not to trap it or bend it too much.

The top of the ST's case is put back on for a moment to see how the drive fits. In this instance the case will need to be edited since the new drive is slightly different than the old drive.
Here mark out where the case will need to be cut.

The case was cut around the eject button of the floppy drive. It will need a little filing down to get it all level but after that your almost done!

You need only need to follow the disassemble steps in reverse to screw your ST back together.

With the High Density Floppy Controller board fitted it only makes sence to fit our High density external drive to the setup!

The revised board has only minor changes.

1) The Black,organge,white wire solder pins have been spaced out a little for more room to solder. The connection remain the same.

2) There is a extra solder pin at the top left of the board ( as shown in the image ). If you have problems fitting the small jumper wire to the ST's metal case then you can solder the wire to that extra pin.

3) if the External drive is not used then it is recommended that the left pin (black wire) be soldered to the extra pin (top of image).