Mikkel,

Sorry for the double post. Until you change your power supply you can't programatically do anything.

You really should be testing with the "final" (or equiv.) supply source. If you can't, then just "lift" the relay power at start up, generate the programatic reset and then reconnect power.

If you are going to use a R/C to generate RESET for the '595's then you better spec a "tight" cap/res combo to guarantee correct operation across time/temperature.

regards,
p