Guide on how to connect a 3.5" drive to a CPC6128/664

From CPCWiki - THE Amstrad CPC encyclopedia!
Jump to: navigation, search

Guide to hook up a 3.5" pc drive to your Amstrad CPC 6128 or 664 (For non-techy people like me).
You can also check out another guide here

This guide is for people who own CPCs 664/6128 with 34 pin EDGE connector type interfaces (sold e.g. in the UK and DK).
For another guide, check Guide_on_how_to_connect_a_3.5.

A 36-pin Centronics connector is used by the German CPC 6128 (classic) and with a dangerously different pinout also by the CPC6128plus, each needing different kinds of cables, cf. DIY:Floppy Drives: Multi-Adaptor Cable for External Floppies & HxC emulator.

What you need (minimum requirements)

- a pc 3.5" floppy drive: For usable models see Drive_Compatibility, Modify_PC_floppy_drives and Adding_3.5"_drive_to_CPC464.
- a old style pc floppy cable - a paperclip or a small piece of wire - a powersource for the drive - a 3.5" floppy disc

Suggest u also get:

- pins & jumpers or maybe some real switches. - tape

The Cable

By some amazing luck the 6128/664 use the exact same floppy-connector as a old 5.25" pc floppy drive. So all you need to connect up is a old style pc floppy cable that has both the old style 5.25" large edge connector and new style 3.5" small pc floppy connector. Hardest part is probably to get one of these cables as they havnt really been used in years. If you have a 486 pc or older, try peeking inside to see if it has one of these cables, then you can easily borrow and replace it with a new style cable.

Looks like so:


But let give you a hand. BELKIN still sells this cable, I got mine locally but this one looks like its the one: ... 36&sr=8-16

This is the 5 connector one, but a 3 connector one may also work if it has the right kind/amount of connectors.

The pc 3.5" Floppy drive

So far all the 3.5" drives ive tested all worked. The question is if you want a drive that is both compatible with 720kb floppies AND 1.44mb floppies. All drives SEEM to work flawlessly with 720kb floppies .. but for some reason .. you get a LOT of read errors with SOME drives when you insert a 1.44mb floppy?

Quick fix: Use 720kb floppies only. 720kb floppies are hard to get, so just make some yourself from 1.44 floppies. Tape over the little "High Density" hole in the top left (both sides). That way the drive will think the floppy is 720kb only and act accordingly. Works Great.


Slow fix

find a drive that works with both size of floppies. I say: a old TEAC FD-235HF drive works with both size floppies. Hearsay from other sites: Alps & Mitsumi drives MAY work fully. One way or the other i use the tape mod on all my 1.44mb floppies because it makes them compatible with all the drives i have.

Paperclip & more

All you really need is one piece of paperclip (the metal kind) to be able to make a single short on the floppy cable, but it would probably be better to get some proper pins and jumpers or some real small wires. Also if you wanna do some really fansy stuff, you might wanna get at least 3 paperclips/wires/pins/jumpers. (se later) Motherboard pins are usually sold in long rows where you can break of smaller parts, like a set of 2 pins, then use normal pc jumpers on em to quickly set on/off.



You need to power the 3.5" floppy drive somehow. A normal pc powersupply will do this quite nicely but there are "complications". A modern powersupply dosnt turn fully on unless it detects a motherboard is present. There is 3 possible solutions to this problem:

1. drag a whole pc up next to your amstrad so u can power the floppy that way.

2. use another way to power the floppy.

3. cheat a modern pc powersupply to think a motherboard is present. Fooling a modern powersupply isnt really that hard .. all u need is to connect the GREEN wire (ready signal) with one of the BLACK wires (ground). This works with both the 20 pin powersupplys and the newer 24 pin ones. Here is a shot of my 20 pin one:


Connected the green pin 14 wire with the black pin 13 wire. Note that i used pin 13 just because it was right next to pin 14 .. but any other black wire will work just as well. The newer 24 pin powersupply can be fixed just like that, but note that the green wire is pin 16 on the 24 pin one. So a possible setup on the 24 pin setup could be green pin 16 connected with black pin 15.

More about powersupply pin layout here

20pin: 24pin:

Note that VERY old powersupplies USED to turn on fully by themselves, so if u have a REALLY old pc u can see if it works.

Setting it all up

All u do is basicly the same as if you would hook up a FD1 drive to a cpc 6128. No soldering or disassembly required. Just hook up the cable to the DRIVE connetor on the Amstrad and the Floppy drive to the next edge connector on the cable. Pretty hard to get it wrong as the edge connector only fits one way and usually the same is said the floppy connector. BUT .. there IS a few floppy drives that have the pins upside down, so u might need to twist the cable around once .. most likely not tho.


Note that this type of pc cable usually has some internally twisted cables .. make sure the CPC/PC does NOT have the twisted bit between them.

IMGP1639 50%.jpg

You can process the same way with only 1 drive 3"5 and 5"1/4 connectors , you can use the 3"5 connector before the edge card connector instead.

Setting the READY signal

Last thing you need to do is set the ready signal. This is done by connecting pin 33 and 34. Its the last 2 pins on the cable. Use a bend paperclip or a small wire to short the 2 pins like so (Marked in WHITE):


Thats it. Now u SHOULD have a fully working 3.5" B drive.

1. Power on the floppy first.

2. Then turn on the cpc.

Errors at this point

- You turn on the cpc but get a blank/rolling screen? Most likely the pc cable connector needs to be flipped over (pins are upside down).

Type "|B" to change to drive B in basic (where ø is the rsx char). A simple CAT will show if the disc/drive works.

Other Errors at this point

Bad Command?
Floppy drive detected by cpc but is not powered. Recheck your powersupply is connected and working.
You turn on the cpc and both drives act-as-one .. and the floppy light is constantly on?
Most likely you didnt short pin 33 & 34
.. is the paperclip/wire loose?
.. or did you accidentally short pin 1 & 2 instead? Try moving the paperclip to the other end of the connector.
Read error on drive? Disc hasnt been formatted yet?
Use software like Discology to quickly format drive B
.. or to quicky copy a disc from A to B
.. or make a test floppy on pc (see transfer bit later).
Disc is write protected error?
Make sure the write tab on the disc is down (move tab down on right side of disc).

Two heads (OPTIONAL)

Ok, everything is working so far? Want to do some more advanced stuff like using 2 sides on your floppy?

Easy enough .. right now your floppy is using head 1 (aka side 1).. if you also connect pin 31 and 32 it will change to side/head 2. Remove the short again to get back to side/head 1. I must admit that i myself only use one side/head because i cant be bother with the switching sides/heads. But it might be worth it if you buy one of them fansy on/off switches from a electronics shop. Pin 31&32 is marked in RED on picture.

Making floppy primary drive(OPTIONAL)

Donno if you have ever tried running software straight from a B drive, but it usually sucks badly (software freeze up). Wouldnt it be nice to if you could turn drive B into drive A (and A into B)? Connect up pin 11 & 12 while the drive is on to do the drive switcheroo. Marked in BLUE (sixth pair of pins from top). Make sure to remove the short after you have turned off the whole thing (or you will get a drives-act-as-one error on next bootup). So you will have to set the 11/12 pin each time you wanna do the drive switching .. This one however seems quite usefull .. off to the shop to get a switch

Another closeup of all 3 pairs of pins without doodlin:


And up and running


Transfering software between CPC and PC:

Yup, a pc can read and write those 3.5" Amstrad formatted floppies. There is a handfull of pc utilities that can read/write to the floppies.

I suggest getting CPCDiskXP by Oscar Sanchez from

It reads a 1 side in about 100 seconds (with verify) .. and writing back 1 side takes about 25 second Runs in Windows XP/Vista using a nice lowlevel driver that you might recognise from Amiga- and Atari ST-discs reading pc tools. Note that you can only use floppies from a INTERNAL floppy drive (a usb one wont work). Seems to me that only the Amstrad is picky about if u use 1.44mb or 720kb floppies .. the pc has no such troubles, so ANY floppy drive may work on pc (from my experience). Also the tape-down-1.44-to-720-floppy-fix works on pc too.

Things that pop'ed into my head reading up on all this

Using a whole pc to power the floppy is getting annoing and uncompfy, so my brain has been thinking in overdrive to come up with a solution.

1. use a normal external-IDE-HDD-USB-enclosure to power the drive .. All you need it the enclosure (with its powersupply) .. then fit a Y-split cable (a IDE-power to Floppy-power one). This is possible if u can find the Y-split cable:


2. use a usb-floppy drive .. dissassemble it and hook it up to pc or Wii or xbox 360 or pc or .. Donno if this is possible .. or if you need yet another type of Y-cable or other. Would look nice with one of them slimline usb-drives.

3. Not a tech wizz at all, but all u need to power a floppy is 5V ?? or do you also need the 12V too? Anyways, a couple of batteries on row might do that easy-ish.

Worries and what not

What if i hook something up wrong will my Amstrad break? Nah, dont think so, I mean I did EVERYTHING wrong at least twice and both 6128 & 664 is still alive and running. Also I tried a LOT of things myself before with a FD1 cable and such. Still we are talking about electronics and all that, so do be carefull, and dont forget that everything should fit nicely .. no reason to force anything. OMG OMG my precius 20+ year old gem of a Amstrad just blew up in my face, will you takes full responsibility and buy me a new one? Eh?, sure i will .. not.


Q: Can I use a FD1 cable to connect a 3.5" floppy drive?

A: In theory yes, but its hard to set the ready signal. Connecting pin 33&34 is probably best done on the drive itself with a small piece of wire/metal. People who can solder will know how to fix the cable itself tho.

Q: Can i hook up a 3.5" to a cpc 464 like this?

A: No. Hooking up a 3.5" isnt possible without some serious soldering and you also need that DDI interface.

Q: Can i use a 3.5" on a 6128+ ?

A: Sure you can, but u need to make a cable that fits the the Centronics connector and since the pins is a bit upside down with the 6128+ its a bit more on the technical side. Look here for more: ... drive.html

Q: I got one of those german Schneider 6128 with Centronics connector?

A: Sure, but just like 6128+ its a bit more technical and need a special interface/cable made.

Look here:

Q: The floppy drive isnt registered at all .. not even getting errors?

A: Try cleaning the connector on the Amstrad.

Q: Can I use those odd format discs on the 3.5" ?

A: 41 track & other Amstrad formats works fine.

Q: Can i use the fully 720kb on the floppy?

A: You need a special rom like Parados to replace Amsdos to do that.

Q: Can i use a 3.5" floppy drive internally in my 6128/664?

A: Well, sure but u need to make another special cable bacause the real internal cable is a lot smaller than the usual pc floppy cable. Also you will need a power converter cable if u want to power the floppy from the inside. If you do use it internally you wont have to set the "primary" pin 11 & 12 as it is already primary.

Thanks goes to

- Executioner, UKmarkh, JMD, Wanderer, Zeropolis79, Gryzor and Ptr for great help and contributions to the guide.

- Everybody in the forums for putting up with my rantings

- Anyone online who i stole info from

Sorry About

I may have made a few assumtions .. especially about the floppy compatability based on from my own experiences and such. If im wrong let me know

My eeiiieenglish isnt the most fluid and correct spelled and all that, but is readable I hope.

Links about 3.5" floppy drive hookup

Guide on how to connect a 3.5 Another local guide

Modify PC floppy drives How to force certain PC drives to produce RDY signal (used for CPC) (Spanish & English) ... e&artid=67 (French) (French) (Spanish) (Spanish)

Great sources about anything CPC (including 3.5" connecting) or (English/French/Dutch/German/Spanish) (German)

Tools to read CPC floppies on pc


ManageDsk: ... es&sortby=



Dsktools "dsktools is a set of tools for reading and writing DSK and EDSK images to real floppy disks for use with theAmstrad/Schneider CPC range of home computers. The main target platform for dsktools is GNU/Linux."