floppy disk drive manuals - test-drb@ccmp.vtda.org

2 Aug 1999

Thanks for the information.  Don Maslin sent some information which it turns
out doesn't apply exactly to my particular drives, as some of the jumpers on
his list dont exist, while others, on the drive, don't appear on the list.
I'm not sure what that means, though.  The drives had paper tags printed
with dot-matrix which are mostly missing, and I'm quite certain the
printed-on-foil labels are not specific enough to account for the different.

Having re-jumpered the drives, they are able to read one another's writing,
though I'm uncomfortable with some of the behaviors certain jumpers produce,
particularly one, which seems to effect the drives differently.

I've had these drives since they were a new product, but haven't looked at
them since a couple of moves before I landed here ten years ago.

I'm not in a hurry now that these drives are available for me to use to
troubleshoot other drives, but when your scanner's back on line, I'd really
appreciate a copy of the bitmaps.

thanx,

Dick
-----Original Message-----
From: Fred Cisin (XenoSoft) &lt;cisin(a)xenosoft.com&gt;
To: Discussion re-collecting of classic computers
&lt;classiccmp(a)u.washington.edu&gt;
Date: Monday, August 02, 1999 2:03 PM
Subject: Re: floppy disk drive manuals

...
 I have the "Operating and Service Manual" for
the Tandon TM848-1 and 848-2
8" drives.  Since I still use some of those drives, I'm not willing to
part with them, but I could get copies made.  Unfortunately it looks like
I won't have a working scanner at all this week.  If you can help me
through what to look up, and teach me what to look for, I'd be glad to
check things for you.  Let me know which sub-model you have.

For example:
for motor speed, on the 848-1, trigger off of R33; for the 848-2, trigger
off of test point 12.

For cat's eye alignment:
Channel A: Test point 2
Channel B: Test point 3
Ground: Test point 1
External trigger: Test point 11, negative trigger, for single sided
drives, R33 is alternatre test point, negative trigger.  Test point 12,
negative trigger for double sided drives.

Tony:
I also have manuals for the Sony D31V and D32V drives!

--
Fred Cisin                      cisin(a)xenosoft.com
XenoSoft                        http://www.xenosoft.com
2210 Sixth St.                  (510) 644-9366
Berkeley, CA 94710-2219

On Fri, 30 Jul 1999, Richard Erlacher wrote:
> I have a couple of Tandon 8" slimline drives (They're in the basement and
> I'm not so no model number.)  They clearly can't read one another's
writing
...
 > consistently, so I'm interested in alignment
data as well as the jumper
> definitions.  Would you have a manual which contains that information?  I
> need to know what the jumpers are and do, and what the factory default
> settings are.  I also need to know where the dif-amp outputs to be used for
...
 > alignment are located, (pin numbers) as well as
the index sensor pin and
> other signals used in adjusting these drives for radial head alignment,
> index alignment, track zero calibration, etc.  If you have it and could
> email me that data, it would help greatly.
>
> regards,
>
> Dick
>
> -----Original Message-----
> From: Tony Duell &lt;ard(a)p850ug1.demon.co.uk&gt;
> To: Discussion re-collecting of classic computers
> &lt;classiccmp(a)u.washington.edu&gt;
> Date: Friday, July 30, 1999 7:23 PM
> Subject: Re: Cromemco 4FDC, How do you format a disk?
>
>
> >> true and for the data I gave the 125kbits/sec rate is too low.  As
it's
...
 > >> minima was 250kbits/s is twice that! 
Part of the recording scheme is
> that
> >> there are rules for continous strings of 1s and 0s, they arent
permitted
...
 > >> to exist for clocking and bandwidth
reasons.
> >
> >I've seen plenty of controllers and data separators that put limits on
the
...
 > >maximum number of consecutive pulses and gaps.
That's why you need clock
> >pulses in MFM recording, and why Apple had the 5-3 and 6-2 encoder tables.
...
 > >I have _never_ seen a drive (and I've read
OEM and service manuals for all
...
 > >sorts of drives) that specify any restrictions
on the user data using the
...
 > >standard encoding schemes
> >
> >At normal 5.25" data rates (125kbps (user bits) FM, 250kbps MFM) :
> >
> >Repeated MFM 0's looks like repeated MFM 1's looks like repeated FM
1's,
> >and consists of pulses every 4 us.
> >
> >Repeated MFM 1010... looks like repeated FM 0's, and consists of pulses
> >every 8us.
> >
> >Now, all drives support user sectors of 1024 bytes (8192 bits), MFM at
> >least (and I don't think this is a real limit of the _drive_ either).
> >That means you could have either of the above patterns for 8192 bits --
> >the user bytes 'touch' each other with nothing between, and there's
> >nothing to stop you having a sector of 0's, a sector of FF's or a sector
> >of 55s if you want it. A disk drive that couldn't store said data would
> >not be useful.
> >
> >I've got a Sony 3.5" drive on the bench at the moment. Now this drive
> >rotates at 600rpm, so you would double the above data rates. Some of the
> >tests involve recording pulses every 2us (corresponding to the first case
...
 > >above) and 4us (corresponding to the second
case above) continuously for
> >one revolution and then playing them back. The service manual for the Teac
...
   FD235 gives tests involving the recording and
reproduction of 250kHz
(pulse every 4us) and 125kHz (pulse every 8us) waveforms.

So it would certainly appear that these 2 drives could correctly handle
FM recording at half the user data rate of the standard MFM encoding. In
other words that Teac (720K) drive would handle FM encoding at 125kbps.

-tony

--
Fred Cisin                      cisin(a)xenosoft.com
XenoSoft                        http://www.xenosoft.com
2210 Sixth St.                  (510) 644-9366
Berkeley, CA 94710-2219