Allows you to connect an original 1.44MB 3.5" PC FDD without any modifications or PC FDD modified for AMIGA. It also allows you to connect a GOTEK emulator (SFR1M44-U100 or SFR1M44-U100K).

(GOTEK, must be set to position S0)

You can connect 3 mechanics in any combination to FDD1, FDD2 and FDD3.

It all depends on the setup of the juper.

NOTICE:

Unconnected drives are displayed in the Workbench system as "DFx:????" it's not a bug, but a function of the adapter.

Settings:

For each drive port (FDD1,FDD2,FDD3)

there are two jumpers available to set the function of the adapter.

JP1 – JP4 for FDD1

JP2 – JP5 for FDD2

JP3 – JP6 for FDD3

The first jumper (JP1, JP2, JP3) is set by DISK CHANGE for the particular drive.

Jumper (JP1,JP2,JP3) positions 1-2 for Gotek or modified PC drive.

Jumper (JP1,JP2,JP3) positions 2-3 for unmodified PC drive.

Second jumper (JP4,JP5,JP6)

sets the SELx signal (DS0 or DS1)

Jumper (JP4,JP5,JP6) positions 1-2 for Gotek or modified PC drive.

Jumper (JP4,JP5,JP6) positions 2-3 for unmodified PC drive.

Both jumpers from a given pair (JP1-JP4,JP2-JP5,JP3-JP6) are always connected to the same position.

Unless we had a partially modified PC FDD where only the SEL signal was modified to DS0 and DISK CHANGE was not modified, then we would have to set: the first jumper position 2-3 and the second jumper position 1-2.

Important:

Jumper JP7 can be connected either with a piece of wire or with a 0 Ohm smd resistor, but do this only if you really need 12V for the drive. Standard FDDs use only 5V.

If you activate 12V, it can easily lead to the power connector being inserted backwards and subsequently destroying the drive or Gotek.

Many thanks: 

Roman Breński, Jarosław Bieliński and Radosław Kujawa for this project.

http://romanworkshop.blutu.pl/elec/amiextfdd.htm

(DIY) C64iSTANBUL

https://www.pcbway.com/project/shareproject/AMIGA_EXTERNAL_FLOPPY_DISK_DRIVE_ADAPTER_bfe5cc33.html

Components:

6x 3 pin 2.54mm (jumper) JP1 to JP6   

2x IC 74LS38 SOP-14 U1,U4

2x IC 74LS74 SOP-14 U2,U3

6x resistor 2k2 Ohm 0805 R1 to R6

2x ceramic capacitor 100nf 0805  C1,C2

3x 4 pin 2.54mm KF2510-A (Male header) power FDD  J1,J2,J3

1x DB23 male (d-sub 23) J4

3x 2x17 (34 pin) 2.54 mm male Socket straight idc headers PCB

4x DIP 14 IC socket

You can make a d-sub 23 connector from d-sub 25 by cutting or 3D printing it and using pins from d-sub 25

https://www.thingiverse.com/thing:1238286

You can download the 3D design of the adapter cover here.

https://www.printables.com/model/1501583-cover-for-amiga-external-3x-fdd-smd-variant

If you would like to print a 3D cover for the 3.5 FDD, here you will find an STL file for several models of mechanics.

https://www.printables.com/model/1441622-cover-for-pc-35-fdd

Advice:

I have seen flat cables that have pin 5 blinded on the connector. Therefore, it is better to remove pin number 5 from the connector on the PCB.