6 Feb
2016
6 Feb
'16
3:27 p.m.
Date: Sat, 6 Feb 2016 00:46:33 -0500
From: Dan K <100dashsix at gmail.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Subject: Re: Calibration of 8" floppy drive?
Message-ID:
<CAAQ+N0XNG=NnWGRnt8oxN4WeXTuoLCXPO9BQRn9oaSjZfVNW
5A at mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Are there any good alternative solutions I can do to replace it? I'm
sure I don't want the plastic touching the disk media.
-Dan
Seems like eons since I learned to align PerSci 299B's with Dysan alignment
disks and 'cat's eyes' on a 'scope :)
I echo the other sentiments here - do NOT undo or unscrew anything relating
to head positions especially involving allen (hex) screws unless you have a
'scope, an alignment disk, a very good quality set of hex screwdrivers (keys
will normally NOT suffice) and a modicum of experience. Granted, lead screw
single-headers are a little easier to do than voice-coil double-headers but
if you don't have to get into it then don't - explore all other options
first.
I'm afraid my TM-848's are double headers so the top head provides the
pressure but back when the drives were single headed felt pads did the job
of the second head. The tension was provided by the spring, the pad just
prevented scoring. I do NOT speak from experience BUT if I had to use
anything the kind of small felt pads you can get from hardware stores (e.g.
B&Q in the UK) seem remarkably similar in composition and would be worth a
try especially if you have one original to compare. Cut to shape, most are
self-adhesive too - bonus.
HTH
James
6 Feb
6 Feb
3:34 p.m.
One interesting thing I noticed (and I'm investigating at this very
moment) is the arrangement of the head load armature. A spring-loaded
arm will swing down and push the felt pad against the media, which
brings it into conformity with the head. However, there's a little
thing on the lever that touches the plastic head load mechanism that I
posted links to earlier.
When the head load solenoid is retracted, the felt pad arm is lifted
up enough that the disk can slide in and out freely. When the head
load solenoid fires, the whole thing comes down and it's clearly
supposed to push on the media. However, I think in both my drives it
doesn't touch it, or if it does it only barely touches it. I'm
thinking perhaps the armature has to come down further.
That being said, at least once I tried doing that, manually letting
the arm come down, and it didn't improve the observed behavior. It's
possible something else was happening then too, so I'll retest.
-Dan
On 2/6/16, James Attfield <james at attfield.co.uk> wrote:
Date: Sat, 6
Feb 2016 00:46:33 -0500
From: Dan K <100dashsix at gmail.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Subject: Re: Calibration of 8" floppy drive?
Message-ID:
<CAAQ+N0XNG=NnWGRnt8oxN4WeXTuoLCXPO9BQRn9oaSjZfVNW
5A at mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Are there any good alternative solutions I can do to replace it? I'm
sure I don't want the plastic touching the disk media.
-Dan
Seems like eons since I learned to align PerSci 299B's with Dysan alignment
disks and 'cat's eyes' on a 'scope :)
I echo the other sentiments here - do NOT undo or unscrew anything relating
to head positions especially involving allen (hex) screws unless you have a
'scope, an alignment disk, a very good quality set of hex screwdrivers
(keys
will normally NOT suffice) and a modicum of experience. Granted, lead screw
single-headers are a little easier to do than voice-coil double-headers but
if you don't have to get into it then don't - explore all other options
first.
I'm afraid my TM-848's are double headers so the top head provides the
pressure but back when the drives were single headed felt pads did the job
of the second head. The tension was provided by the spring, the pad just
prevented scoring. I do NOT speak from experience BUT if I had to use
anything the kind of small felt pads you can get from hardware stores (e.g.
B&Q in the UK) seem remarkably similar in composition and would be worth a
try especially if you have one original to compare. Cut to shape, most are
self-adhesive too - bonus.
HTH
James
9:50 p.m.
It figures: after all this talk about neither of the drives working, I
plugged one of them in (the one that's in better condition) and it now
recognizes the disk. The felt pad presses on the media, at least very
lightly, and perhaps this is the source of the main problems in the
other drive.
Other issues I didn't mention: the metal front panel that prevents the
disk drive from opening too far is broken on one of them, and the
latching mechanisms on both drives don't work, so that I have to wedge
something on top to keep the disks engaged. I also haven't tested the
reliability of the drives, as in writing a ton of data and verifying
it.
I noticed you changed the destination to cctech instead of cctalk,
James. I'll try to do that in the future for on-topic-only
discussions, as I suspect that's the custom here.
-Dan
On 2/6/16, Dan K <100dashsix at gmail.com> wrote:
One interesting thing I noticed (and I'm
investigating at this very
moment) is the arrangement of the head load armature. A spring-loaded
arm will swing down and push the felt pad against the media, which
brings it into conformity with the head. However, there's a little
thing on the lever that touches the plastic head load mechanism that I
posted links to earlier.
When the head load solenoid is retracted, the felt pad arm is lifted
up enough that the disk can slide in and out freely. When the head
load solenoid fires, the whole thing comes down and it's clearly
supposed to push on the media. However, I think in both my drives it
doesn't touch it, or if it does it only barely touches it. I'm
thinking perhaps the armature has to come down further.
That being said, at least once I tried doing that, manually letting
the arm come down, and it didn't improve the observed behavior. It's
possible something else was happening then too, so I'll retest.
-Dan
On 2/6/16, James Attfield <james at attfield.co.uk> wrote:
Date:
Sat, 6 Feb 2016 00:46:33 -0500
From: Dan K <100dashsix at gmail.com>
To: "General Discussion: On-Topic and Off-Topic Posts"
<cctalk at classiccmp.org>
Subject: Re: Calibration of 8" floppy drive?
Message-ID:
<CAAQ+N0XNG=NnWGRnt8oxN4WeXTuoLCXPO9BQRn9oaSjZfVNW
5A at mail.gmail.com>
Content-Type: text/plain; charset=UTF-8
Are there any good alternative solutions I can do to replace it? I'm
sure I don't want the plastic touching the disk media.
-Dan
Seems like eons since I learned to align PerSci 299B's with Dysan
alignment
disks and 'cat's eyes' on a 'scope :)
I echo the other sentiments here - do NOT undo or unscrew anything
relating
to head positions especially involving allen (hex) screws unless you have
a
'scope, an alignment disk, a very good quality set of hex screwdrivers
(keys
will normally NOT suffice) and a modicum of experience. Granted, lead
screw
single-headers are a little easier to do than voice-coil double-headers
but
if you don't have to get into it then don't - explore all other options
first.
I'm afraid my TM-848's are double headers so the top head provides the
pressure but back when the drives were single headed felt pads did the
job
of the second head. The tension was provided by the spring, the pad just
prevented scoring. I do NOT speak from experience BUT if I had to use
anything the kind of small felt pads you can get from hardware stores
(e.g.
B&Q in the UK) seem remarkably similar in composition and would be worth
a
try especially if you have one original to compare. Cut to shape, most
are
self-adhesive too - bonus.
HTH
James
3020
days inactive
3021
days old
2 comments
2 participants
participants (2)
-
100dashsix＠gmail.com -
james＠attfield.co.uk