This is my process of diagnosis on the emax II
first thing i checked was the power supply .. which in this emax is non standard
its been upgraded and the supply rails are stable and no sign of ware
or damage .
so with that ruled out i moved onto the floppy drive
Powered the system with floppy drive attached -- Result ( Checking
Floppy - System Locked )
Powered the system with my pc floppy drive attached -- Result (
Checking Floppy - System Locked )
Powered the system with no drive attached -- Result ( Checking Floppy
- System Locked )
in all 3 cases the diagnostic lights on the front showed an error with
either floppy drive or controller
pdf for diagnostic
http://synthark.com/synthesizer-museum/emu-gallery/emulator-archive/manuals/so as i knew my drive was working but it failed in the emax and it
failed with no drive attached as well i surmised that it was the
controller chip at issue ..as the original emax drive reacted like my
working drive .. i took it that the drive was ok
.. so next was to do some research to find out which chip was the
floppy controler
a bit of googling and help in this forum post ...found it to be the WD1772-ph 02-02
after locating it on the pcb i discovered it was soldered directly to
the pcb rather than in a socket as in later versions of the emax :/
i had to take the sampler completely apart so i could get to both
sides of the pcb
this made the job of replacing it considerably more difficult as there
are 28 legs to de solder on both sides of the pcb to remove it ...
which is quite tricky to do
once the chip was removed and all the lpads cleaned up i then fitted a
28pin dip socket for the new chip to sit in .. so that if ever goes
again it will be a simple job to replace the chip
rebuilt the sampler
Powered the system with floppy drive attached -- Result ( Checking
Floppy - System Locked )
Powered the system with my pc floppy drive attached -- Result (
Checking Floppy - checking scsi ...looped )
this lead me to believe that when the chip went originally that it
took the drive with it .. or vice versa
then this morning i took a standard floppy drive and did a small modification and
swaped the drive id from d1 to d0
. plugged it back into the emax .. and it boots
working sampler
just need to screw it all back together
Photos coming soon
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