Amiga 2000 Floppy Drive problem

[Dwight K. Elvey]

Hi
 Has anyone mentioned measuring the voltages on the control
pins. It would be good to know if it was the controls
or the drive.
Dwight

>From: "Ethan Dicks" <ethan.dicks at gmail.com>
>
>On 7/1/05, Teo Zenios <teoz at neo.rr.com> wrote:
>> Jumper 301 is still in the open position (for a single drive).
>
>Perfect.
> 
>> 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).
>
>OK... swapping the 8520s and watching the symptoms was a pretty
>standard method back in the day - it's easy and it works, so that
>_probably_ shows your 8520s are OK.
> 
>> 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).
>
>That _is_ a key (and needs to be in any Amiga hardware FAQ - I can't
>remember how many times we had to tell people that in our Amiga club -
>every novice who added an internal floppy use to call us up and ask
>how to "replace a broken pin"... they thought that the
>pin had become stuck, and they must have pulled it out when they
>messed with the cable.
> 
>> 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).
>
>And they support the /DISK-EXCHANGE signal (p 34?)   That was what
>always hosed frugal early-adopters of the Amiga - they'd try to use a
>cheap floppy, and the OS wouldn't be able to step the drive in and out
>one track to get the drive to assert the /DISK-EXCHAGE (or whichever
>one it was) so that the drive could 'tell' the OS that the diskette
>that used to be there isn't there any more.
>
>You _can_ hook up a floppy drive that won't assert that signal, but
>that places a burden on the user's head to have to type an AmigaDOS
>command to flush the previous diskette's particulars and to cache the
>new diskette.
>
>-ethan
>
>