AT A1200 and internal floppy change....

[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

[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

[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

[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

[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