18 Jan
2005
18 Jan
'05
12:19 p.m.
From: ard(a)p850ug1.demon.co.uk
[mailto:ard@p850ug1.demon.co.uk]
To: cctalk(a)classiccmp.org
I'll see if anyone in the local radio club has any I could borrow for a few
evenings. I know how to use one, it's just been a few years. I have an old
Heathkit scope behind me, but there's another thing waiting for my
attention. The trace is about as wide as my pinky and as noisy as heck. Not
real helpful I'm afraid.
I don't kwow what it means when I reply to my
own replies,
but here goes. I
I do it all the time, but then I am know to be insane...
have the same continuity measurements on head 0
and head 1.
However, if I swap the controller board
the problem
stays with the drive.
Ah, so it certainly looks like a head problem :-(
So, if I have the same continuity, and the problem doesn't
seem to be on the
controller, I can only guess either dirty or magnetized
heads.
Magnetized heads are not normally a problem with floppy
drives, at least
not as big a problem as dirty heads.
It's a pity you don't have a 'scope. I'd ask you to connect it
(differential inputs) to TP1A and TP1B, ground to TP2. Those are the
outputs of the read preamplier part of U2 (3470). You could
then compare
the read signal from the 2 heads.
Since I don't have access to a tape head demagnetizer (hey,
all I use is
DTRS for my recording), how else could I demagnetize these heads?
Can you not still buy demagnetizers? There are plenty of magnetic
recording heads still in use...
But I would try really cleaning it first. It could be a speck of oxide
stuck across the gap or something.