I have heard that Micropolis 1325 is prone to have a problem with a rubber 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 > >

Den l?r 2 jan. 2021 kl 11:48 skrev Rob Jarratt <robert.jarratt at ntlworld.com Did you solve the problem? How? I have heard that Micropolis 1325 is prone to have a problem with a rubber 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 ------------------------------

-----Original Message----- From: cctech <cctech-bounces at classiccmp.org> On Behalf Of Mattis Lind via cctech Sent: 05 January 2021 17:52 To: David Gesswein <djg at pdp8online.com>; General Discussion: On-Topic Posts <cctech at classiccmp.org> Subject: Re: ICL PERQ 2 T2 Micropolis 1303 spinning down. Den l?r 2 jan. 2021 kl 19:34 skrev David Gesswein via cctech < cctech at classiccmp.org>: signal. 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: > > 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 > there > > > 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 > rubber > > 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 > > > > > > > > > > > > ------------------------------ >

The "shim" method worked fine. The drive spun up and I managed to dump it. Imade six dumps and the same five sectors were bad on every read I did.

So now I have a nice dump of the PERQ 2 system. Wonder what it is on it?

I am dealing with this a *lot* with all these disks from Bob's basement. The problems seem to be three categories: 1) Disk does not spin up at all. So far it's all been sticking motors, they don't have a lot of start up torque at all. For the first 4 disks (ST412, Quantum 30mb, and two ST506) I was able to remove the bottom board, turn the disks manually (clockwise) while applying power to spin them up. The motor will start to turn, then as you continue to spin it with your finger it will go faster as the oils distribute themselves. Note: I need to figure out how/if I can oil drive motor bearings without opening them or ruining the seal. 2) Stepper/coil motors are stuck. This is easier to deal with on the ST412,Quantum,ST506 drives as there is literally an arm on the side you can move. These can be oiled externally if needed. On the RD53, the heads were stuck internally, what I did was unlock the heads manually (open bottom panel and turn the locking cam) while tapping the drive on the side with the palm of my hand. This could work, but hit it too hard or sharp and you will crash the heads. Maybe I could use the rubber hammer.

3) Controller board caught fire and exploded. Yes, this burned my rug with flying debris, it can happen. Have a fire extinguisher handy. I am thinking of building a small dust free space to open the tops of other drives. Not sure if this is an immediate death sentence, a lot of these drives have filters inside that could probably handle one or two openings worth of dust, but man that is an edge case. In the old days I built a tent over my RM03 disk and counted on its absolute air filter, but I don't think I can do that with RL02's as the fan for the absolute air is also the disk spindle motor.... Then again the Diablo 44 is always running the fan but I haven't found a source of air filters for that yet (unlike the RL02).

from the Micropolis drives that where schematic are available on bitsavers

Meantime, anyone know how to convert one of Dave G's disk images on the MFM formatter to a format that can be read by SIMH? I have been working a lot with this thing, and would like to see if any of the data is really there.