Hello everyone.

Thanks for all the help.

Just to add to the fun --- i already have a 1000uF a/c the o/p of +5V.

The 12V is an unregulated supply (have always used regualted +12V in all previous designs, had to save space this time). Maybe i'am paying for the folly. I'll keep u'll posted once i put a reg. +12V for the relay supply.

There is no load connected to the relay contacs!! The erratic problem happens usually when the relay switches OFF (back emf.). But then there is a diode soldered right on the relay !!!

The inductor was put (yes, desperate attempt) in the hope that transients would not go from the 12V gnd to the 5V gnd.

Thank u all for your help,

Zoojar L
I have tried diff. (make & ratings) relays --- just in case !!!! No luck.