Re: Hidden power switch for Widgets?

Am Sonntag, 25. Januar 2015 20:28:27 UTC+1 schrieb Tom Stepleton:

I'm not sure what would be required for that to work, but my recollection
> is that it can't be as simple as putting a switch between some/all of the
> power lines and the drive. I think I once tried disconnecting just the
> power connector (and not the data ribbon cable), and the green drive LED
> lit up anyway, even though the drive mechanism was still. If that memory is
> accurate, some of the data cable's lines must also need to be disabled to
> truly leave the Widget "off".
>
To disable the Widget you can just interrupt the motor +12V, leaving all other voltages connected. The selftest will be aborted in case the spindle does not spin up, therefore the head brake keeps engaged. However, the drive is still visible to the Lisa and it will wait until timeout before trying to boot something else.

Pin 19 of the Sub-D25 connector (or the equivalent pin on the 26pin header) is an "open cable detect" signal. It has a pullup inside the Lisa and is tied to ground in the device. It may sufficient to cut this signal to make the drive invisible to the Lisa. Try this with the IDEfile first before cutting the Lisa drive harness.

Regards
Patrick

-- 
-- 
-----
You received this message because you are a member of the LisaList group.
The group FAQ is at http://lowendmac.com/lists/lisa.html
To post to this group, send email to lisalist_at_email.domain.hidden
To leave this group, send email to lisalist+unsubscribe_at_email.domain.hidden
For more options, visit this group at http://groups.google.com/group/lisalist
--- 
You received this message because you are subscribed to the Google Groups "LisaList" group.
To unsubscribe from this group and stop receiving emails from it, send an email to lisalist+unsubscribe_at_googlegroups.com.
For more options, visit https://groups.google.com/d/optout.



text/html attachment: alternate version of message