Spinning up RL02 w/o head load ? (was Cleaning RK05 packs)

Pete Turnbull pete at dunnington.plus.com
Sat Jan 7 03:42:28 CST 2017

On 07/01/2017 04:08, Robert Armstrong w#rote:
>> Paul Koning <paulkoning at comcast.net> wrote:
>> one would think unplugging the power to the head actuator coils  ...
>   One might think that, and that plan works for an RK05, but an RL02 is
> smarter.  Unless the heads go on cylinder within a few seconds of the head
> load signal, the drive logic just faults and spins down again.  Not very
> useful...  What's needed is a way to stall or fake out the drive startup
> state machine logic.

I haven't done this for a while, but I think it might work if you also 
disable the SK TO (Seek Timeout) signal on the main logic board, and 
maybe also POS SIG (Position Signal).

There are several setup and adjustment procedures that require one to 
move the heads by hand, including right back onto the loading ramp. 
You'd do this with the cover open, the logic board swung up and resting 
on its clip at the back of the drive, and with the amplifier box turned 
to a vertical position sitting on its right-hand supports.  The 
procedures require the above signals to be disabled, and the servo drive 
(the single inline connector under the amplifier box) to be 
disconnected.  However, they all start by pressing LOAD and allowing the 
heads to load at least as far as the loading area at the outside edge of 
the disk before disconnecting the servo drive; I can't remember if the 
heads actually go beyond that into the area where the data tracks are.

How you disable the signals depends on the version of the main logic 
board - there are three different types, all described in the pocket 
service guide.

Pete Turnbull

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