5 Jan
2021
5 Jan
'21
9:51 a.m.
Den l?r 2 jan. 2021 kl 19:34 skrev David Gesswein via cctech <
cctech at classiccmp.org>:
This is my info on RD53 sticking heads. Your symtoms
match what I have seen
with this drive.
If the heads are stuck to the rubber bumper the drive will spin back down
when it finds the heads won't move. It will also spin down if it can't
switch from the coarse speed control loop to using the head servo signal.
There is a narrow band where the heads are parked with the proper signal.
When the rubber has deteriorated the heads are no longer over it. Adding
shims
can fix that. I used a tent with RK05 filter but others have opened drives
in reasonably clean locations sucessfully. Best to keep the pets away.
http://www.pdp8online.com/rd53/rd53.shtml
Shim picture.
http://www.pdp8online.com/rd53/pics/lock.shtml?small
Thanks. Good advice and good prictures! Need to find some material that
makes a good shim then. It will be very interesting if this solves the
problem. I wonder if the other symptom I saw where the drive kept spinning
while the head was moving back and forth also is related to the first? It
didn't sound like full seeks but rather quite short. The drive kept doing
this for maybe one minute and then spun down.
/Mattis
On Sat, Jan 02, 2021 at 02:05:11PM +0100, Mattis Lind wrote:
there
rubber
------------------------------
Den l?r 2 jan. 2021 kl 11:48 skrev Rob Jarratt
<
robert.jarratt at ntlworld.com
:
> When that has happened to MFM disks of mine it has been because for one
> reason or another the heads have not moved and found track 0. Why they
> aren't moving could be more than one reason. They could be stuck, or could be
some other problem that is preventing them getting the power
needed to move.
Did you solve the problem? How?
I have heard that Micropolis 1325 is prone to have a problem with a bumper that sticks to the head mechanism. Maybe
it is the same for this
Micropois drive? What resolutions are there to this type of problem?
/Mattis
>
> Regards
>
> Rob
>
> > -----Original Message-----
> > From: cctalk <cctalk-bounces at classiccmp.org> On Behalf Of Mattis
Lind
> via
> > cctalk
> > Sent: 02 January 2021 08:59
> > To: General Discussion: On-Topic and Off-Topic Posts
> > <cctalk at classiccmp.org>
> > Subject: ICL PERQ 2 T2 Micropolis 1303 spinning down.
> >
> > I have a nice ICL PERQ 2 T2 that I am going to start working with
now.
> >
> > First thing was to try to image the hard drive. It is a Micropolis
1303.
> It spins
> > up but when it reaches what I think the correct speed it immediately
> spins
> > down. Usually I think there would be a click and then the heads would
> > recalibrate. But there is no click and no head movement.
> >
> > I really would like to make an image of the drive. What are your
> thoughts?
> > Are the heads sticking?
> > Some kind of solenoid that is not releasing the heads? Not properly
up
to
speed? (but it sounds like the speed is right)
/Mattis