Hello crews,
I have an ancient Astec AA16990 PSU from the first generation Power Macintosh (about 1993). The computer was fully functional until the last month when I noticed that the floppy drive has suddendly stopped working. This brought me to the idea to check the PSU first.
The cover lists the following output voltages to be supplied:
+5Vdc, 11.6A (red cable)
+12Vdc, 2.5A (yellow cable)
-12Vdc, 0.5A (blue cable)
However, a quick multimeter check shows the following output voltages:
red cable --> +4.4Vdc
yellow cable --> +7Vdc
blue cable --> -4,4Vdc
All voltages seem to be out of expected range which could explain the floppy drive failure.
I bet the PSU need a major recapping due to the age of the unit that still seems to contain original components from 1993.
I counted 12 electrolytic capacitors by Nichicon on the PCB, with no visible traces of bulging, leaking etc (see attached pictures).
Because I have a rather limited experience with PSUs, I'd to ask the experts here about what to do in order to fix it?
Thank you in advance!
I have an ancient Astec AA16990 PSU from the first generation Power Macintosh (about 1993). The computer was fully functional until the last month when I noticed that the floppy drive has suddendly stopped working. This brought me to the idea to check the PSU first.
The cover lists the following output voltages to be supplied:
+5Vdc, 11.6A (red cable)
+12Vdc, 2.5A (yellow cable)
-12Vdc, 0.5A (blue cable)
However, a quick multimeter check shows the following output voltages:
red cable --> +4.4Vdc
yellow cable --> +7Vdc
blue cable --> -4,4Vdc
All voltages seem to be out of expected range which could explain the floppy drive failure.
I bet the PSU need a major recapping due to the age of the unit that still seems to contain original components from 1993.
I counted 12 electrolytic capacitors by Nichicon on the PCB, with no visible traces of bulging, leaking etc (see attached pictures).
Because I have a rather limited experience with PSUs, I'd to ask the experts here about what to do in order to fix it?
Thank you in advance!
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