Re: Modern replacement power supplies for Apple ProFile hard drive?

The controller doesn't finish a write in progress if the power fails, whether there is enough energy in the capacitors or not (I suspect not).

If you know what part is bad, fixing the PSU seems to be the path of least effort to me.

Otherwise, since I expect you aren't putting anything on the ProFile that you can't afford to lose, I suggest you connect PowerOK directly to +5V and see if you actually get any evidence of spurious writes. Since the ProFile automatically parks after a few seconds of inactivity, normal power-up and power-down is unlikely to be a problem.

>I found out in the ProFile service manual that the AC signal is
>actually a POWER OK signal.

>Once a
>failure is detected, the head current is shut off to prevent the
>accidental writing of false data that would otherwise occur if a
>write operation were to process when the power failed.

>If the mains were to shut off, there is
>enough power stored in the capacitors to allow the controller board
>to power the ST-506, empty the cache to the hard drive, and then
>properly shut down.

-- 
-- 
-----
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/groups/opt_out.