Unfortunately these drives are not compatible with standard drives. They have a single 26-way cable connector, which although it may look like the connection to an Amstrad 3" drive has a different pinout and carries three 5 volt lines instead of a separate power cable. Do not confuse these drives with Citizen drives with standard 34-pin and separate power supply cable; these are widely available in 720K and 1.44M configurations.
As a standard 3.5" drive has a 34-way connector, the 26-pin Citizen has an obvious incompatibility with it, but equally, a 26/34 way cable made to connect an Amstrad 3" drive to a 3.5" standard drive will not work either and may do some damage.
The pinout for the Amstrad 26 pin 3.5" Citizen drive is as below.
Pin No. Function
1 5 Volts 2 Index 3 5 Volts 4 Drive Select 0 5 5 Volts 6 Not connected 7 Drive Select 1 8 Ready 9 Not connected 10 Motor on 11 Not connected 12 Direction 13 Ground 14 Step 15 Ground 16 Write Data 17 Ground 18 Write Gate 19 Ground 20 Track 0 21 Ground 22 Write Protect 23 Ground 24 Read Data 25 Ground 26 Side 1 Select
By looking at the file on making a cable for a 3" to 3.5" standard and using the table above it is possible to see how a PcW9512+, a PcW9256 or PcW10 could be converted to use a 3.5" standard drive as a B: drive etc. but I haven't done so yet. It looks as though the same problem with the READY signal arises as discussed in the file. The power supply problem shouldn't arise as these machines will have a more robust 5 Volt supply.
Ron King
Email address.... ron@king27.freeserve.co.uk