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Top Secret 12
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Top Secret 12.adf
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1991-08-15
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³¼WRITEPROTECTED AND¼³
³¼WRITEENABLED-SWITCH¼³
¹
This little modification should be
at some use for nearly all Amiga
owners, because it can avoid viruses,
do copying easier etc. etc. If you
only want to have a switch that
writeprotects all drives at the same
time, it can be done much more easy
than if you also wants a writeenabled
switch. So, lets take the easy first...
First you have to locate the right CIA
chip with the numbers (U7 & 8520).
When this is done find leg 5 and solder
a small wire to it. The wire should
now be soldered to the middle pin on a
on-on switch and the other pin on the
switch should be soldered to ground
(pin 1 on same chip). Thats it. The
first position on the switch is ALL
drives writeprotected (even if the disk
is unwriteprotected). And the other
position is normal ('disk-controlled').
And now, lets go on with the more ad-
vanced type. As written before, find
leg 5 on the right CIA-chip. Pick out
the chip and bend the leg (#5). Now
solder a wire from the leg to the
upper pin on a on-off-on. The midd
le pin should be connected to the
fifth 'hole' in the socket. Put the
chip back in the socket and solder the
last pin on the switch to leg one
(ground) on the chip. Again, thats it.
You now have writeenable on the
middle position of the switch. Write
protected in the other position and
'disk-controlled' in the last position.
The simple way this switch works, is
to make use of the WPROT-signal. When
low (connected to ground) ALL floppy
drives are writeprotected and when con-
nected to nothing (high) ALL drives are
unwriteprotected. If you have any pro-
blems in the unwriteprotected posi-
tion, it's maybe a good idea to sol-
der a 1 Kohm resister from pin 20 on
the CIA (+5v) to pin 5 on the same CIA.
This is because I'm not 100% sure if
the CIA-chips are tri-state or not.
I do not think they are but anyway.....
³The technical Mailbox
Co. Jacob Blichfeldt
Langelandsvej 1A
7400 Herning
Denmark
Hawkeye/Kefrens