On 8/18/2015 4:11 PM, tony duell wrote:
>
>> Yeah, but the TIP31A part is cheap, and is free air mounted on its leads
>> - it isn't screwed down. I'd rather do the repair nicely. Anyway, it
>
> Sure...
>
> What I would do is bolt a tag + wire onto the tab of the old transistor (don't
> tell
> Yeah, but the TIP31A part is cheap, and is free air mounted on its leads
> - it isn't screwed down. I'd rather do the repair nicely. Anyway, it
Sure...
What I would do is bolt a tag + wire onto the tab of the old transistor (don't
tell me you don't keep solder tags and small nuts/bolts (M3,
On 8/17/2015 11:14 PM, tony duell wrote:
>>
>> Well, in the process of repairing the Altos power supply I managed to
>> break the center lead off of the TIP31A that feeds the 2N3055 series
>> pass transistor. This time, I need to order parts.
>
> Do you? The centre lead (collector) is connected
> The bearings were actually easy to replace, no special tools required.
> The hardest part was getting off the nut that was holding the spindle
> together.
Nothing to do with this drive (in fact I have never seen this in 8" drives)
but some direct drive 5.25" drives have a left hand thread screw
>
> Well, in the process of repairing the Altos power supply I managed to
> break the center lead off of the TIP31A that feeds the 2N3055 series
> pass transistor. This time, I need to order parts.
Do you? The centre lead (collector) is connected to the tab on that transistor.
So a
solder tag
Well, in the process of repairing the Altos power supply I managed to
break the center lead off of the TIP31A that feeds the 2N3055 series
pass transistor. This time, I need to order parts.
In the meantime, I swapped drives to make the problem more drive accessible.
Also, the Shugart 801 drive I
The bearings were actually easy to replace, no special tools required.
The hardest part was getting off the nut that was holding the spindle
together.
Other than that, the bearings side into place pretty easily (the top
one, which is the most critical, required the heel of my hand to press
it in p
On Mon, Aug 17, 2015 at 5:22 PM, Jay Jaeger wrote:
> Well, in the process of repairing the Altos power supply I managed to
> break the center lead off of the TIP31A that feeds the 2N3055 series
> pass transistor. This time, I need to order parts.
Isn't the center lead also the tab?
> Also, the
I'd always wondered why that was so.It has been handy to see which
were 360K as I don't think HD everhad the donut ( maybe rare ).Dwight
On Sun, 16 Aug 2015, Chuck Guzis wrote:
Where I saw the problem was with the Micropolis 77-track (single sided) 100
tpi drives.
Their 35 track 48tpi ss drive
On 08/16/2015 08:46 AM, dwight wrote:
I'd always wondered why that was so.It has been handy to see which
were 360K as I don't think HD everhad the donut ( maybe rare ).Dwight
Where I saw the problem was with the Micropolis 77-track (single sided)
100 tpi drives.
--Chuck
> From: ccl...@sydex.com
snip
> I believe that the earlier Micropolis 5.25" floppy drives worked the
> same way. I recall that when they first came out, they'd mangle the hub
> area of a floppy because the spindle motor often had been turned off by
> the host. Eventually, the design was mod
On 08/15/2015 09:49 PM, dwight wrote:
Sorry about the error in which side has the cone and which side has
the cylinder. I don't have a 800 here in front of me to look at. It
still doesn't make any difference if the moving arm is a little off.
The piece that is mounted on the arm is designed to fl
Sorry about the error in which side has the cone and which side
has the cylinder. I don't have a 800 here in front of me
to look at.
It still doesn't make any difference if the moving arm is a little
off. The piece that is mounted on the arm is designed to float
on the spring. It is still the spind
On 08/15/2015 08:55 PM, Jay Jaeger wrote:
On 8/15/2015 8:31 PM, Jon Elson wrote:
On 08/14/2015 02:58 PM, Jay Jaeger wrote:
No, I didn't write any of what was quoted. ;) If one is going to remove
the entire message quoted, then it probably makes sense to delete the
"wrote" line as well. ;)
On 8/15/2015 3:13 PM, Jay Jaeger wrote:
>
> To make matters worse, that test with the first SA 801 managed to smoke
> the 24V power supply on this system, so now I have to pull it all apart,
> and pull out the regulator transistor which is mounted from the reverse
> side through to the board and
On 8/15/2015 8:31 PM, Jon Elson wrote:
>
> On 08/14/2015 02:58 PM, Jay Jaeger wrote:
No, I didn't write any of what was quoted. ;) If one is going to remove
the entire message quoted, then it probably makes sense to delete the
"wrote" line as well. ;)
>
> The way most of the old 8" floppies wo
On 08/14/2015 02:58 PM, Jay Jaeger wrote:
The way most of the old 8" floppies work is they have a cylinder with an
ID that matches the ID of the floppy hole. The floppy sits against the
face of the cylinder, and a plastic, springy cone is pressed into the
cylinder by a bearing and spring on
On 8/15/2015 1:55 PM, tony duell wrote:
>
>> Certainly one of my thoughts along the way. But, the spindle cone does
>> not rock or anything like that. And, I switched the clamping part out
>> with another drive - neither was affected by the swap.
>
> It strikes me that there are 3 main subasse
> Certainly one of my thoughts along the way. But, the spindle cone does
> not rock or anything like that. And, I switched the clamping part out
> with another drive - neither was affected by the swap.
It strikes me that there are 3 main subassemblies associated with clamping the
disk :
The c
On 8/15/2015 1:35 PM, tony duell wrote:
>
>> Not so on these drives. On the Shugart SA-800 series, the spindle
>> (driven by a belt from a motor) has a MALE cone on the end, and the
>> clamp, from above goes around it (female if you like).
>
> I have just pulled the case on one of my HP9885s, w
On 8/15/2015 12:32 PM, tony duell wrote:
>>
>> Not so on these drives. On the Shugart SA-800 series, the spindle
>> (driven by a belt from a motor) has a MALE cone on the end, and the
>> clamp, from above goes around it (female if you like).
>
> How does that work? The disk media must fit around
> Not so on these drives. On the Shugart SA-800 series, the spindle
> (driven by a belt from a motor) has a MALE cone on the end, and the
> clamp, from above goes around it (female if you like).
I have just pulled the case on one of my HP9885s, which uses an SA801
chassis and HP electronics. Th
On 8/15/2015 11:59 AM, Chuck Guzis wrote:
> I went and stared at some of my 8" drives for a bit this morning.
>
> It occurs to me that if your top guide frame is laterally "warped", the
> centering of the hub clamp assembly won't work.
Agreed. But the darn thing is cast, with lots of fillets fo
>
> Not so on these drives. On the Shugart SA-800 series, the spindle
> (driven by a belt from a motor) has a MALE cone on the end, and the
> clamp, from above goes around it (female if you like).
How does that work? The disk media must fit around that male cone. Is the
complete disk carried by
On 8/15/2015 11:51 AM, tony duell wrote:
>
> In every 8" (and 5.25") drive that I've seen the spindle (the bit driven,
> maybe
> indirectly, by the motor) has a female cone on the end. There is then the
> clamping
> cone, often plastic which fits into it through the hole in the disk.
Not so on
On 8/14/2015 11:56 PM, tony duell wrote:
>
>> There is no play in the spindle at all. Certainly not 1/2 track worth.
>> Can't wiggle it at all, no visible wobble, etc.
>
> Not necessarily play. Anyway, half a track width is just over 10 thou
> and I am not sure I could notice that amount of ru
I went and stared at some of my 8" drives for a bit this morning.
It occurs to me that if your top guide frame is laterally "warped", the
centering of the hub clamp assembly won't work.
If you've got a wiggler gauge handy, you may want to see what the
deviation is when the hub clamp mates wit
> Except that when the media is aligned to the spindle correctly, the
> drive performs flawlessly, including exchange with another drive. If
> the spindle itself were wobbling so much as to cause the other symptoms,
> I don't see how it could ever work right.
> On these drives, the centering co
Certainly this thing is old enough. But I don't see how it would ever
work if that were the case.
When the media is on center, it works flawlessly, including interchange
with another drive.
One thing I am going to try today is to manually center the media with
the AC power disconnected (not spin
On 8/14/2015 11:56 PM, tony duell wrote:
>
>> There is no play in the spindle at all. Certainly not 1/2 track worth.
>> Can't wiggle it at all, no visible wobble, etc.
>
> Not necessarily play. Anyway, half a track width is just over 10 thou
> and I am not sure I could notice that amount of run
It could be an indication of pot metal failure.
I had one drive that the spindle from the driven side was clearly
swelling. I replaced it from a spare parts drive.
What happens is that the metal has oxidation at grain boundaries.
It is said that it is caused by small amounts of contaminating
metals
>There is no play in the spindle at all. Certainly not 1/2 track worth.
> Can't wiggle it at all, no visible wobble, etc.
Not necessarily play. Anyway, half a track width is just over 10 thou
and I am not sure I could notice that amount of runout by eye. Also
I have learnt by bitter experience t
On 8/14/2015 3:01 PM, tony duell wrote:
>
>> The clamping is not out of alignment. If it were, the results would be
>> more consistent. Besides, the clamping is not really responsible for
>> the alignment. It is a matter of the media relationship to the spindle
>> as the clamping comes down on
> The clamping is not out of alignment. If it were, the results would be
> more consistent. Besides, the clamping is not really responsible for
> the alignment. It is a matter of the media relationship to the spindle
> as the clamping comes down on it.
The fact that it sometimes centres proper
On 8/14/2015 1:33 PM, Chuck Guzis wrote:
> On 08/14/2015 09:27 AM, Jay Jaeger wrote:
>
>> When I look at the cartridge guide without the spindle clamp in
>> place, it is now centered above the spindle, and at the same distance
>> from the spindle as my drive that does not have these issues.
>>
>>
On 8/14/2015 2:01 PM, Fred Cisin wrote:
> On Fri, 14 Aug 2015, Jay Jaeger wrote:
>> I have a Shugart 800-8 with a media centering problem. I know it is
>> definitely that and not something else (say, electronics, TRK00
>> position, etc.), because I can see the "wobble" in the signal coming
>> fro
On Fri, 14 Aug 2015, Jay Jaeger wrote:
I have a Shugart 800-8 with a media centering problem. I know it is
definitely that and not something else (say, electronics, TRK00
position, etc.), because I can see the "wobble" in the signal coming
from the heads on a 'scope.
If all thge disks were for
On 08/14/2015 09:27 AM, Jay Jaeger wrote:
When I look at the cartridge guide without the spindle clamp in
place, it is now centered above the spindle, and at the same distance
from the spindle as my drive that does not have these issues.
Anybody have any experience like this? Thoughts? There
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