Calibration of 8" floppy drive?

[Dan K]

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
>
>
>