E-mu Emulator Sampler User Forum for the EIII EII EI and EIII XP

after recently repairing a friends emu ultra 6400 .. which had a power supply issue ive been given this emaxII to repair

ive had it open and had a look and there are no component failures that i can see

upon power up it shows on the lcd screen checking floppy . and that is where it stops

i hear no seeking on the floppy drive


am i correct to presume that its a dead floppy drive

here is a set of photos ive uploaded on my facebook

https://www.facebook.com/media/set/?set=a.10153080903654572.1073741864.573014571&type=1&l=0c4a58594e

Tested another floppy drive today and its doing the same.

Floppy light comes on .. no seeking .. says checking floppy and there it stops

Any ideas folks

sounds very much like a bad WD1772 (floppy controller chip).

Anything I can do to find out...maybe remove clean and re seat the chip

Yeah you could try that or just buy a new one. Furthermore I would check the PSU..

Any idea where I might get a new one?

....  ::)

http://lmgtfy.com/?q=buy+wd1772


& ebay,...,...

thanks i did google it myself ... i just was not sure if it was a chip that required programming prior to instillation and in that case i would need one programmed for the emax II  ... however i guess from your response that its just a generic chip and it should work right out the packet

none the less im going to try and clean it first ... and check all the other chips  for leg corrosion

ive located that chip on the board as well .. and noticed its not in a socket .. so its not likely to be corroded legs

i really dont want to have to de-solder it unless i have to ... is there any way i can test this to be 100% that the chip has packed up

are there other things i should be checking first

Hm, that's bad...

My E-mus had sockets. Well I repaired my 5 Emus and 2 had broken WD1772. I'm just a hobby tech so I don't know how to test it.

done a spot of research on the chip

here is a data sheet if anyone needs it

http://www.milton.arachsys.com/nj71/pdf/Roland/wd177x.pdf

seems its been used in all sorts of gear not just the emax ...

The floppy disk controller (FDC) in the W-30 is a Western Digital WD1772, the same controller as used in the Atari ST, Ensoniq SQ80, the Commodore 1570/1571 and 1581 disk drives, the Acorn BBC and Master series computers, and Andre Fachat's CS/A65 6502-based homebrew computer system.


there are a few versions .. although from what i have read they are all backwards compatible


attached is a photo of my wd1772-ph  02-02

found some diagnostic manuals for free

http://synthark.com/synthesizer-museum/emu-gallery/emulator-archive/manuals/

The diagnostic lights also lean towards floppy drive or controller chip .

So I'm ordering one from eBay tomorrow ...will let you guys know how it goes

Parts arrived today... will most likely be doing the repair on Sunday...

Will post my results and photos

Well i removed the old chip which was quite hard job .. with dual layer pcb ... wish it had been in a socket ...

well now i have a socket fitted on the board with a brand new WD1772-ph 02-02 installed

put the whole thing back together .. and the same issue ... checking floppy ..nothing

so i found another floppy drive ... which i used to test it with initially .. pluged it in ... went past checking floppy and onto checking scsi ... however it still did not boot ...

so im thinking there was an issue with the drive and the chip

found this pdf of jumper settings for various floppy drives

http://freaknet.org/asbesto/roba/diskettes-jumpers.pdf

so im going to make sure the drive i have is set to ID0

and have another go

wish me luck

modified another drive to d0 and she lives ... will post photos later too

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

Photos

http://www.facebook.com/media/set/?set=a.10153080903654572.1073741864.573014571&type=1&l=0c4a58594e

Did you check if the IDE cable or the pin-layout for the floppy-drive isn't broken?

Kind regards,
Frank

i never changed the floppy cable ... the problem was with the controller chip and the floppy drive its self .. once both were replace all was fine