> >> around 7.3 volts no-load (it's rated at 5v, 2 amp).
> > 
> > How do you regulate/limit that down to 5V ?
> 
> I don't :)

I think you mean "Oh no ! I don't ;-(((((((("

Absolute maximum rating for a 628 is 6.5V. You're asking
for trouble running it over 5.5V. The problem is that your
PIC isn't taking anywhere near 2A (admittedly you're doing
your very best to make it do so ;-) ) and so the voltage isn't
going to drop significantly below 7.3V with a temporarily
healthy PIC

The LEDs can be run on the 7.3V, although the more you
have on, the dimmer they'll get, but the PIC must be down
at 5V-ish. The margin between 7.3 or 6.2 is too low for a
78L05, you'll have to use a low drop-out (LDO - there are
a few common ones around like the LP29xx) regulator, or,
as so much power is being used by the LEDs anyway, a 5V1
zener. The zener's series resistor, together with a reservoir
cap on the PIC side, say a few 100uF, should give you a
smooth stable PIC 5.1V

Your PIC's aren't dying, they're being murdered. You, you,
you .... murderer you ;-)

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