Amiga 2000 Floppy Drive problem

[Teo Zenios]

----- Original Message ----- 
From: "Ethan Dicks" <ethan.dicks at gmail.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Sent: Friday, July 01, 2005 1:30 AM
Subject: Re: Amiga 2000 Floppy Drive problem


> On 7/1/05, Teo Zenios <teoz at neo.rr.com> wrote:
> > I was messing around with my Amiga 2000HD today (installing a 2.04
Kickstart
> > Rom to replace the 1.3 Kickstart among other things) and now my internal
> > floppy is dead. The drive worked fine after I changed the rom and the HD
and
> > installed workbench 2.04, it was when I reassembled the system and
rebooted
> > I noticed the floppy was no longer working. I took the drive out and
didn't
> > notice any smell or burnt traces (as if I had the power connected
backwards
> > and it fried), any way to troubleshoot one of these things (Chinon
FB-354)?
>
> Hmm... given that there isn't _one_ FDC chip - perhaps you could check
> your 8520s?  Those control the floppy digital signals (presuming your
> problem is that the drive doesn't light up, as opposed to a spinning
> floppy that won't read - that can be analog electronics or Paula).
>
> You could remove the drive, check carefully for shorts so you don't
> fry another machine, and try it on another machine (as DF1, to be most
> helpful).
>
> I'd also make sure you didn't dislodge the DF1 jumper on the
> motherboard - the A2000 is quirky in how it supports drive selects and
> internal/external drive numbers.  This shouldn't affect DF0, but it
> _will_ affect DF1.
>
> I guess I should have asked first - you do have the schematics, don't
> you?  They are at the back of the Tech Ref manual if nowhere else (for
> pre-v6 mobos - not sure where to find late-model schematics).
>
> I guess the point is - determine if it's the Amiga or the floppy drive
> first.  As for troubleshooting the drive itself, I don't know that a)
> there's enough information to successfully poke around in the innards,
> or b) you'd be able to find parts to fix if it you could.
>

Jumper 301 is still in the open position (for a single drive).

The two 8520's looked ok (nothing shorting pins together or stuff like that,
no signs of overheating). I swapped the 2 chips around and still have the
same result (external Df2: works while the internal DF0: is dead).

I checked the floppy cable and didn't see anything out of the ordinary
(except a pin in what looks like position 2 of the cable but I think that is
a key, since the motherboard does not look like it has a broken pin on it).

At this point I think it either the floppy cable has a bad line, or the
drive is just dead. Since the amiga cable does not look like a standard
floppy cable I think I will try setting the drive for Df1: and shorting
Jumper 301 to see if its recognized at all.

I did some research and quite a few older DD 3.5" PC drives can be jumpered
to Amiga mode (ofcourse I don't have any on the list).