Apple II Plus EOL

[rummikub32@yahoo.com (Iosaef the Irascable!)]

Hey all!

I finally got my grubby paws on an Apple II Plus.  Nice unit, 48k +
16k language card, Epson APL board, Disk II controller, etc.  Well,
the string of problems with this unit (PSU lost its magic smoke,
apparently bad RAM chip somewhere, dead Reset and Shift keys) has led
me to post a question:

On Apple IIs as old as the Plus and original IIs are, what have people
here found to be going out most often?  I've read around about the PSU
failures, and 25+ year-old capacitors blowing out isn't all that
surprising.  But what about other failures or wear points in their
machines?

Just on an up note, I've got the Plus on a IIe's power supply for life
support, and the RAM failure seems to manifest itself in the HGR2
screen, in a cheesy BASIC screensaverish thing I wrote for my IIe. 
Vertical lines through the screen, but no other artifacts in other
video modes.

Take Care!
Josef