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
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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
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If the I.D.# for the analog board is 676-[]101 or 676-[]102, use a pair of
nippers to cut out resistor R8 (located at position A2).
If the I.D.# for the analog board is 676-[]107, use a pair of nippers to cut
out resistor R39 (located at position C3).