AT A1200 and internal floppy change....

[StormLord]

I have an A1200 from escom that uses the "called" Pc HD floppy drive...
Recently my drive got dead and I thought that a PC drive will work OK..
BUT.. nope..
Then I search the aminet to find some info , and that got me more confused, because I found info for making a AT mobo compatible with old one Also I found a cable hack to add a PC drive to commodore mobos! But I didn't find how to add a PC drive to AT mobo just to use it as an 880k drive!!
If you have heard anything or have some experience please post! you may be very helpful!

[RedskullDC]

PC Floppy drives won't work out of the box on your Amiga.

You will have to:

1) Force the drive to use Double Density.
PC's use pin 2 on the connector to switch DD/HD.
Cut the trace from Pin 2 of the drive cable connector.
Connect the DRIVE side of the trace cut to a GND point, this will force the drive to DD mode.

Some drives will ignore this signal when you insert a HD floppy disk. Not a problem, since you shouldn't be formatting HD floppies as DD anyway due to the different write-head current used.

2) Locate the 'DiskChange' signal on the drive.
Most drives will have a jumper which selects either 'RDY' or 'DC' to appear on pin 34. The Amiga expects it on Pin 2.
When you locate 'DC', connect it to the AMIGA side of the trace cut you made in step 1.

3) Change the Drive Select jumper from DRIVE #1 and change it to DRIVE #0. Some more recent drives are hard-wired as Drive #1. You may have to do a little investigative work.

That should be all you need to do.

Cheers,
Red

[StormLord]

WOW! Thats what I call TOTAL answare!.
Maybe the tread closed before it begins! :-)
thanks very much
I searched some floppy drives I have and none of them has a jumper for rdy/dc select... also none of them has drive select jumper.. actually there is no jumper at all at the back of the drive .. I will open one to see if it has some internal.... also because these drives are very recent maybe its DRIVE1.. is that a problem or it just the amiga recognise it as DF1: ??
Thanks.

[StormLord]

I opened and searched an ALPS 1.44 pc drive and I've done the DD modification by cuting the trace on pin 2 and ground it. I also found the DS0 jumper and I closed this and opened DS1. But I can't find anything for RDY (READY?) signal on the PCB..
Its a new drive so I belive it has just the diskchange to pin 34. I could cut the trace from pin 34 and connect it to pin 2 that the amiga expects the diskchange but what about RDY that must be presents at pin 34 on amiga ? Anyone knows what signal is it? I mean is it a high or low signal and when it appears and disapears? I'm asking that to see if it possible to generate this signal somehow or to find it on the drive..

[RedskullDC]

StormLord wrote:
Its a new drive so I belive it has just the diskchange to pin 34. I could cut the trace from pin 34 and connect it to pin 2 that the amiga expects the diskchange but what about RDY that must be presents at pin 34 on amiga ? Anyone knows what signal is it? I mean is it a high or low signal and when it appears and disapears? I'm asking that to see if it possible to generate this signal somehow or to find it on the drive..

No, don't cut the trace on pin 34. Leave the RDY signal there.

You need to find the Diskchange signal, and route it to the Amiga side of the trace cut on pin 2.

Do you have a part no. for the drive? serial no.?
Perhaps a hires pic of the circuit board?
May make it possible to locate the DC signal, or do a web search for the tech info.

Red

[RedskullDC]

Incidentally, the drive will work without making the "DC" jumper, but you will have to use the old "C:Diskchange dfn:" command, that used to be used for ancient 360k 5 1/4" drives that didn't have a Diskchange signal.

Red

[StormLord]

RedskullDC wrote:

No, don't cut the trace on pin 34. Leave the RDY signal there.

But I belive Pc drives has the diskchange on pin 34 and not RDY...

You need to find the Diskchange signal, and route it to the Amiga side of the trace cut on pin 2.

If I'm correct on the above the diskchange signal already apears on pin 34 of pc drive, so I can redirect it to pin 2 that the CBM amiga expect it. the problem is how to find the RDY signal..
I searched the web for pc drives pinout and I show stating diskchange on 34.. is this wrong ? I must say that the drive I'm using is not the drive from an AT A1200 but from my pc..

Do you have a part no. for the drive? serial no.?
Perhaps a hires pic of the circuit board?
May make it possible to locate the DC signal, or do a web search for the tech info.

Red

the drive is ALPS electric DF354H090F with S/N:4A536915
I did a web search but only german pages appeared and I don't speak or read german :-(
I can't have hires pics before monday  :oops:

[RedskullDC]

StormLord wrote:

But I belive Pc drives has the diskchange on pin 34 and not RDY...

PC's normally use RDY on pin 34. They ignore the Diskchange signal entirely.

If I'm correct on the above the diskchange signal already apears on pin 34 of pc drive, so I can redirect it to pin 2 that the CBM amiga expect it. the problem is how to find the RDY signal..
I searched the web for pc drives pinout and I show stating diskchange on 34.. is this wrong ? I must say that the drive I'm using is not the drive from an AT A1200 but from my pc..
the drive is ALPS electric DF354H090F with S/N:4A536915
I did a web search but only german pages appeared and I don't speak or read german :-(
I can't have hires pics before monday  :oops:

I had a quick look at the german pages you mentioned, and on the ALPS site for their 3.5 docs.
Nothing of a very technical nature. The pics will help hopefully.

Red

[delshay]

HD DRIVE

i have a HD DRIVE when fitted to A1200 ( internal )rev 2B it sees both HD & DD disk..


when same drive fitted to A1200 ( internal ) rev 1D4 only sees it as DD drive.

[RedskullDC]

delshay wrote:
HD DRIVE

i have a HD DRIVE when fitted to A1200 ( internal )rev 2B it sees both HD & DD disk..

when same drive fitted to A1200 ( internal ) rev 1D4 only sees it as DD drive.

Manufacturer?, Model No?
Kickstart version in each machine?
Be more specific huh?

When you say 'it sees bot HD & DD' do you mean it will format/read both 880k and 1.76M disk formats?

Red

[delshay]

@redskulldc

both a1200 by commodore
both a1200 kickstart 3.1

in the rev 2b it can see amiga 880k & 1.7m..useing ms dos driver its 720k & 1.44mb.


when fitting the same drive in a a1200 1D4, only sees amiga 880k & on the ms dos side it sees 720k.

NOTE: no software is reqd..

i think i need to remove a resistor on the A1200 1D4 near the floppy connector.
but which one?..


its great having HD disk,as games that took more than one disk or anything else for that matter i just roll into one disk but cant use it on my 1D4..

[RedskullDC]

delshay wrote:

both a1200 by commodore
both a1200 kickstart 3.1
i think i need to remove a resistor on the A1200 1D4 near the floppy connector.
but which one?..

Sorry, I meant who is the manufacturer of the floppy drive?
Do you have a part no.?

Red

[StormLord]

After searching with lot of drives , I couldn't find the diskchange signal.
After experiment I found how we can easily create it and connect it to pin 2 of the drive that the amiga expectit. I found that in we give a LOW signal (bridging it to ground) to pin 2 the amiga starts searching the drive with the known famous "click", thats does not change when we insert a disk, but when wth a disk inserted open the pin2 from ground the drive access the disk and apearing it to desktop :-)))
I wanted to use a "push-off" switch inside the drive thats when the disk is inserted to open pin2 from ground... After some though I decided to use one of the buttons that the drive has already for write/protect, DD/HD, motorON/OFF, I decided to use the motorON/OFF switch but because these switches are working the oposite I wanted (its push ON) I used a small 5v relay glued at the back of the drive. And now I have a NEW! amiga drive compatible with old progs that want ready and diskchange signal together.
The procedure are :
1) First find a drive that has DS0/DS1 jumper or solder pads and change it to DS0, alternative if you cannot find this and because new PC drives are configured as DS1 you can use a PC floppy cable with the twist, the results are the same and the drive reacts as DS0 (DF0)
2) cut with a blade the trace on the drive going to pin2 and connect the cutted trace to a ground (all ODD numbered pins except 3 are grounded) becarfull not to connect pin2 on the ground but the other side of the cut. this is for the drive to become Double Density.
3) get an SMALL 5v relay that has pins that is connected if the relay does not work. Connect one pin of the inductor of relay to 5v of the power connector and the other pin of the inductor to the MotorON/OFF button pin that is not connected to the ground until the button is pushed
4) finaly connect the pin2 of the drive and pin1(ground) to the the pins of the relay that is connected when the relay is not working and glue the relay somewhere.
DONE! enjoy your new amiga drive and start waching State Of THE Art demo! :-)
EDIT: its much simpler to do it that to describe it!!

[delshay]

@REDSKULLDC

i dont have the name of the drive..to get this i will have to take the drive cover off..

the drive has a extra cct board on the outside ( plugs into drive interface)..

i think i got the above drive from POWER COMPUTING along with a external HD drive..

the external is in a metal case,again no name.. will need to take apart to find name..


the external HD drive works ok on 1D4..but no internal..


NOTE: the extra cct board is not needed for some HD drives
as i can plug-in the external drive to the internal drive slot & still get HD & DD..

the extra cct board must be a converter for some drives to activate HD drive.


the drives have no effect on performance...i can still boot from NDOS type disk..