Den lör 2 jan. 2021 kl 19:34 skrev David Gesswein via cctech < cct...@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. > 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 see things like : --------------------------------------------------------------------- ! LoadDisk.Cmd ! Copyright (C) 1983, 1984 - Perq Systems Corporation. ! Abstract: ! Load version G.6 of POS onto the hard disk. so there is some PERQ stuff there at least. > > http://www.pdp8online.com/rd53/rd53.shtml > > Shim picture. > http://www.pdp8online.com/rd53/pics/lock.shtml?small > > > 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.jarr...@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-boun...@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@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 > > > > > > > > > > > > ------------------------------ >
