Thanks for your reply. I’m pretty confident of the power supply I’ve been using. It’s one of our lab bench HP power supplies, and I periodically verify the voltage needle on the supply with a DMM. I’m running one 0.1uF capactor per IC, placed directly between the Vin pin of each IC and ground, but I haven’t acutally monitored the behavior of the voltage on a scope while the board was in operation. I think I’ll put that on my to do list for my next visit to the lab.