In your first post, you mentioned “The servo runs off a separate power supply, so it can't be a power issue.” However, your schematic contradicts this.

It sounds like the servo might be pulling your power supply down enough to upset (continually reset) the 876A – this could be the cause of the sputter you describe as it "restarts" each time. Can you describe your power supply setup for us?

You might want to try 1) increasing the size of the capacitors on both sides of the regulator and 2) adding some decoupling and bypass capacitors as close as possible to VDD and VSS on the 876A. Let us know ...

Good Luck,

Paul Borgmeier
Salt Lake City, Utah
USA