unidisk 5,25 analog board #2 doesn't write

[myemail@fattimi.ei (Andrea)]

Hello, I have this unidisk 5,25" silver version that does read but
doesn't write or format disks. The problem is in the analog board since
the mechanics work fine with the board of another drive.

I opened the case, it mounts the analog board #2 and I noticed that the
IC in position IC3 74LS367 is larger than its socket, it's quite
strange, isn't it? 
Unfortunately the types of ICs are not written on this kind of analog
board as it happens with the previous one, so I can't check if this is
the correct chip for that position.
Then I noticed that the drive works the same way even without any chip
in IC3, this is making me believe more strongly that the 74LS367 is
wrong in IC3.

Can anyone check what is the right chip for IC3 or provide me schematics
for this analog board #2 ?

Thanks in advance
Andrea


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