A1200 second floppy

[Nbdy]

Hi,

Have read many pages that I found On google for a second floppy even a Pc floppy mod for Amiga ...

Now the question : Can the second (PC floppy with mod) be added to A1200 only soldering wires to the DB23 port connector with any hardware between the floppy and the amiga ???

All I have read and shematics seen, it should be possible only leaving the DS1 on PC floppy connected (not modding to DS0) ???

THX

[hooverphonique]

If "mod" means obtaining a READY signal from the drive, then the "any hardware" must include an ID pulse generator so the Amiga will recognise the drive (if it's DD, this is quite simple), and a latch circuit for the floppy motor.

[alexh]

I think he means PC 720k floppy disks which have their PCB changed so diskchange is pin 2, ready is pin 4

http://jope.fi/drives/

1.44mb drives additionally need the HD rotation speed changed from 300 rpm to 150 rpm. (There are very few drives that support this mod)

[hooverphonique]

Originally Posted by alexh

I think he means PC 720k floppy disks which have their PCB changed so diskchange is pin 2, ready is pin 4

Yes, if you're using a ribbon cable connector at both ends, modifying the drive pinout is important, of course (like an Amiga-internal drive).
If soldering discrete wires to the DB23 connector, you can skip this, including changing the drive to DS0, because you would just connect the wires to where they need to go.

[Nbdy]

So there is no need for some hardware between the DB23 and the drive ???

Just wires ???

[alexh]

Originally Posted by Nbdy

So there is no need for some hardware between the DB23 and the drive? Just wires?

For HD you need a particular drive and that drive needs the disk drive PCB modifying.

For DD some floppy disk drives work with just wires (internally). Some don't.

Ian Steadman created an open-source bit of HW that works for every PC floppy disk drive (by recreating the missing nREADY signal).

http://ianstedman.co.uk/v2-x-floppy-drive-adaptor/

"The design is simple, it swaps connects Diskchange from pin 34 of the PC drive to pin 2 of the Amiga. It generates the nREADY signal based on the nSEL0 signal and nINDEX, which signals to the Amiga that the drive is ready for access. Latches the MTRx signal to allow use as an external floppy disk drive"

Other people still make them today.

https://www.ebay.co.uk/itm/333509649554
https://amigastore.eu/440-amiga-exte...dapter-m1.html

[Nbdy]

OK, I have 4-5 Mitsumi/NEC/TEAC floppy drives which I have moddet to work with Amiga ...

Noticed that I need to place a tape on the HD hole on the disk to read them (I could sloder also the switch) ...

Do I need to change the DS0 back to DS1 on the floppy board, or if I connect the wires I should just change the wire to the SEL0/SEL1 pin ???

Will try to made just the cable as a cheap solution ...

Have a head full of information, now just to take the right one

THX for advices

[Jope]

Noticed that I need to place a tape on the HD hole on the disk to read them (I could sloder also the switch) ...

This is normal. When you're reading/writing DD bit rates, you want the drive to be in DD mode. Whatever signal processing and filtering it does is matched to the bit rate, along with the magnetizing current.

Please note, some drives will no longer detect diskchanges if you solder the HD detect switch, so keep this in mind and check with the drive as your first internal drive to see that it still works after this modification.

Do I need to change the DS0 back to DS1 on the floppy board, or if I connect the wires I should just change the wire to the SEL0/SEL1 pin ???

This depends on the external floppy adapter you use. Normal parlance is to route the lowest select from the D23 to DS0 on the flat cable, but this is not always the case. You must check for yourself.

Will try to made just the cable as a cheap solution ..

You will need the motor latch and id stream generation, so a solution with 7474 + 7438 chips (or equivalent) is needed if you want to connect an Amiga modded floppy drive to the Amiga's D23 connector. A straight cable will not do, the drive will not be detected and the motor will pulse on/off.

[Nbdy]

Originally Posted by Jope

You will need the motor latch and id stream generation, so a solution with 7474 + 7438 chips (or equivalent) is needed if you want to connect an Amiga modded floppy drive to the Amiga's D23 connector. A straight cable will not do, the drive will not be detected and the motor will pulse on/off.

OK, so a solution without the hardware is not possible ..


THX