Re: dual 5.25 disk drives apple brand

[giorgio.morocutti@alice.it]

Il Fri, 29 Oct 2010 07:59:25 -0400, Steven Hirsch <snhirsch@gmail.com>
ha scritto:

>On 10/29/2010 07:17 AM, Sam Latella wrote:
>> Hi,
>>
>> I've got a quick question on a dual combo 5.25 disk drives that are apple
>> brand.  This dual drive came with the apple //e I just inherited.  It uses
>> an apple I/O card on the apple IIe (not a disk II card).  Now my question is
>> can I use this dual 5.25 drive on the IIgs by just plugging into a 3.5 drive
>> or directly into the smartport on the IIgs?  It would make life easier in
>> creating 5.25 disks for the IIe.
>
>I believe there's a resistor that needs to be cut off the circuit board to 
>make it cooperate with 3.5" drives on the SmartPort.  Unfortunately the 
>details are lost in the mists of time...
>
>Anyone remember?
>
This is a cut and paste from an Apple doc.txt:


This evening, I received with great appreciation, the Duodisk mod I
had been
asking for. They were courtesy of John Daniels
(ah499@cleveland.freenet.edu).
He asked me to post it here so that others could benefit as well. Here
goes!

+---------------------------------------------------------+
          
Subj: Duodisk Modifications
 
There are TWO modifications that should be made to Duodisk drives.
 
The first one was recommended by Apple perhaps 5-6 years ago, to solve
occasional problems with trashing diskettes by Duodisks.  The solution
is to
remove 2 capacitors.
 
The 2nd modification is only required for Duodisks to be used on Apple
IIGS's
(though the modified Duodisk will still work fine on older Apple
II's).  It
requires removing a resistor.  The problem is that the Duodisk draws
just a
little too much current. This problem is especially apparent when
several
drives are daisy-chained from the GS Smartport. Problems are MOST
likely to
occur when the Duodisk is daisy-chained from a Unidisk 3.5 Drive.
 
DUODISK MODIFICATION - REMOVAL OF CAPACITORS
 
OK, here's the first modification for the Duodisk drive.  This mod
should be
done on ALL Duodisks, no matter whether they're used on //e's, IIGS's,
etc.
The problem was that diskettes would sometimes be damaged when doing
an
Open-Apple-CTL-Reset, or when using disks with certain kinds of copy
protection.  The mod was in an Apple dealer service bulletin several
years
ago.
 
Here's an excerpt from the bulletin, describing the problem:
 
  "Data on disk is damaged when using "Open-Apple-CTL-Reset" for
rebooting,
  or when using software with certain copyright protection schemes.
  Analog board PN is 676-[]101 or 676-[]102."
 
The Analog board is the one inside Drive 1 in the Duodisk.  You may
have to
unplug the cable near the back right of the board to see the board's
model
number.  Anyway, if you have the -101 or -102 board, just break off or
cut
out Capacitors C29 and C30 (at board locations A1 and B1,
respectively).
 
I've done this on all 3 of my Duodisk drives, so I can vouch for the
safety
of the procedure.
 
DUODISK MODIFICATION - RESISTOR REMOVAL
 
Here's the second modification for your Duodisk drive.  This is the
exact
message as posted on Compuserve in 11/86 by an Apple Computer
employee:
 
**********************************************************************
 
Duodisk Mod                13-Nov-86 1150               Accesses: 12
 
    This file describes how to modify your duodisk for safe use on the
GS.
    Obviously, it is preferable that you have it done by the dealer,
but if
    you want to do it yourself here's the info... Questions/problems
to
    76703,3030, PM
 
Using the DuoDisk with the Apple IIGS
 
The DuoDisk can not be used as the last daisy chained device on the
built-in IWM disk port of the Apple IIGS. For instance, a UniDisk 3.5
will be rendered inoperable when the DuoDisk is installed in the above
manner - although using the DuoDisk by itself is not a problem.
 
A qualified technician will have to modify the DuoDisk analog
board if the DuoDisk is to be used as the last device on the
chain. Please use the following procedure to determine how to
modify the analog board.
 
IDENTIFYING WHICH ANALOG BOARD YOU HAVE
          
Remove the top cover as documented in Technical Procedures. Turn
the drive so that the I/O connector is facing toward you. The
identifying number will be at the bottom left of the analog
board. The number might read 676-[]101, 676-[]102 or 676-[]107.
 
PERFORMING THE MODIFICATION
 
If the I.D.# for the analog board is 676-[]101 or  676-[]102, use
a pair of nippers and cut out resistor R8 (located at position A2).
 
If the I.D.# for the analog board is 676-[]107, use a pair of
nippers and cut out resistor R39 (located at position A1).
 
Ciao

Giorgio


Apple II and Apple III forever !!!