ICL PERQ 2 T2 Micropolis 1303 spinning down.

[Chris Zach]

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).

Hm.

CZ



On 1/2/2021 3:59 AM, Mattis Lind via cctalk wrote:
> 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
>