Re: Just got a possible prototype Widget disk - any special considerations?

Here's a nice wobble-cam video of the drive attempting to come up:

https://www.youtube.com/watch?v=eFRTS87hTBQ

-J

On Tue, Dec 30, 2014 at 2:21 PM, Jason Perkins <perkins.jason_at_email.domain.hidden> wrote:

> Good to know about the motherboard.
>
> Patrick, did you check out the pictures I posted? It looks like the
> mounting stands were never fitted to the servo board. Were they screw / nut
> on early versions?
>
>
> https://lh5.googleusercontent.com/-V4qbUsfa-UA/VKH8-Z9ysEI/AAAAAAAAF0o/ly3O9bKFnBY/s800/IMG_20141229_200128.jpg
>
> I did carefully shake the drive and didn't hear any rattles. Upon powering
> it up it spins fine, unlocks the head brake, does the initial squeak squeak
> then seems to get stuck doing the same operation over and over. From your
> notes this would be the r-w test on the spares track. At least the bearings
> are all quiet.
>
> I presume this means the drive needs to be low-level formatted?
>
> Thanks,
>
> -J
>
> On Tue, Dec 30, 2014 at 1:35 PM, PSchaefer <dr.p.schaefer_at_email.domain.hidden> wrote:
>
>>
>> Am Montag, 29. Dezember 2014 20:25:00 UTC+1 schrieb compu_85:
>>
>> > -No apple serial number sticker on the front, instead a 4 digit SN
>> > is written in pen (my other 2 widgets have 5 digit SNs on an Apple
>> sticker)
>>
>> ...and sometimes the serial number is stamped onto the chassis.
>>
>> > -The Read/Write and Servo boards are different part numbers than
>> > my other 2 drives
>>
>> There are two PCB designs with different part numbers, and each comes
>> with at least five revisions (marked from A..Z). Also for the controller --
>> the old one is a small four-layer board, the new one a bigger two-layer
>> design.
>>
>> > -The MotherBoard has green edge connectors vs. the black on
>> > my other 2 drives
>>
>> ...and some have blue connectors. The same applies to the stopmask of the
>> bareboard: there are many colors between yellow an green.
>>
>> > -The heatsink on the Servo board was trimmed
>>
>> That is unusual and might be an indication that someone repaired the
>> drive and needed access to the servo board. Replace it with something
>> bigger if you want to operate the drive for a longer time. The servo driver
>> transistors do get hot.
>>
>> > I was going to pop in the controller from one of my other drives and
>> see what
>> > happens. However, if there is anything "interesting" on the drive I
>> don't want to
>> > risk damaging / erasing it. Are there any special steps I should take?
>>
>> Before powering up, shake it carefully and listen for loose parts inside.
>> There is a glass scale inside, a part of the servo system. This is glued to
>> the chassis frame. The glue ages, and if the drive is bumped, it may come
>> loose. If this part gets into the motor, the whole inside of the drive is
>> turned into dust. Unfortunately a very common failure mode.
>>
>> As the next step, rotate the motor flywheel carefully. If it rotates
>> without any irregularities, apply power. After some 30 seconds, you should
>> hear a clicking noise, followed with a "squeak-squeak". If not, turn it off
>> and check and adjust the brake solenoid on the bottom. Put the drive upside
>> down, so that the heads do not move the heads while the drive is not
>> spinning.
>>
>> After the initial "squeak-squeak", the controller board performs a self
>> test, then a RW test on a spare track, and finally a surface scan. If
>> everything passes and the green light stays on, you can use BLU to create
>> an image file. Else, swap boards to identify the faulty one.
>>
>> Do not touch the adjustment screws on the motherboard unless you know
>> what to do. Do not bend the motherboard or lift the drive using it as a
>> handle -- this may misalign the pots. Do not swap motherboards, this will
>> not work without realignment. And never never never open the drive (unless
>> you are sure that it is scrap).
>>
>> If you know what to do: circuit diagrams and alignment instructions are
>> on bitsavers.org.
>>
>>
>> Patrick
>>
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>
>
>
> --
> Jason Perkins
> 313 355 0085
>

-- 
Jason Perkins
313 355 0085

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