23 Mar
1998
23 Mar
'98
4:37 a.m.
On Sun, 22 Mar 1998, Don Maslin wrote:
All I can see through the back is what looks like a blue 16-pin DIP chip
in a socket labeled "2F" in drive B and not drive A. This is probably the
jumper plug you're talking about. I can't see the top surface, so I can't
see if there are straps, broken or otherwise. I could probably remove the
thing from drive B, but inserting it into the other drive would be
impossible without removing the drive from the metal housing.
Of course, if I simply removed the part from drive B, and connected the
ribbon cable to B and not to A, it might work. I'd rather not have
another loose part to keep track of until I get the right tool to
reinstall the thing, though. :/
Doug Spence
ds_spenc(a)alcor.concordia.ca
Interesting! Take a look at the back side of the
II's drives and see if
you can identify the small black 'cable' that leads to the head. It will
move as the heads move. Anyway, if you spot two, then the machine has
double sided drives and that could be the reason that the 2's drives -
single sided - cannot read the disk.
Both machines have single-sided drives, and the disk I have is definitely
single-sided.
If you compare the part numbers on the motherboards -
assuming that they
are there - you will find that the board on the II is an 81-110, whereas
the 2 should be either 81-184 or 240. They are not the same board.
The 2 has an 81-240A. I can't find a number on the II's motherboard.
Anyway, the
only other thing I could try is to make drive B in the 2 think
that it's drive A, to see if I can boot from there. Does anyone know how
these drives decide which one's A and which one is B? And can I switch
their identities without removing the drives from the metal housing? I
don't have the proper screwdriver to remove the drives.
This is usually set by a socketed DIP jumper plug on the drive circuit
board located near the ribbon cable connector. It could be a DIP switch,
but not usually. If the DIP jumper plug and they are both in the same
position, just swap them. If they are in different positions, then swap
the positions on both drives. These DIP jumper plugs have a frangible
strap between opposing pins, and usually all but one or two are broken.