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

Yup, I'm starting to head in the direction of just servicing the PSU. I did find the Apple power supply document that shows both the schematics and the parts list for both types of ProFile power supplies (AA11770 and AA11771).

On Mon, Dec 23, 2013 at 7:48 AM, James MacPhail <gg__at_email.domain.hidden>wrote:

>
> 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.
>>
>
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