adric22 wrote:
> I just opened up the power supply.  None of the capacitors appear to
> be blown, but I know sometimes just old-age will get them.  Are there
> any particular ones that are more prone to failing than others?  There
> are quite a few in there and it would take a while to replace them
> all.

The prime suspects are the (usually two) higher voltage electrolytics
near the power connector.  When they lose capacitance, the power to the
switcher is decreased to the point where it cannot maintain regulation.

You can diagnose them by paralleling both with a pair of similar
capacitors prior to desoldering the old ones and replacing them.

The voltage rating should be as high or higher and the capacitance
rating should be equal to as much as 50% higher.

-michael

******** Note new website URL ********

NadaNet and AppleCrate II for Apple II parallel computing!
Home page:  http://home.comcast.net/~mjmahon/

"The wastebasket is our most important design
tool--and it's seriously underused."
--- SBBSecho 2.12-Win32