Hi David,

Just a quick question. Have you metered your power supply for the proper output voltage? I know it sounds elementary but based on what I'm reading here nothing is working! Nothing on either of your 3 boards. Try removing the micro from the socket, apply power and read for proper voltage at pins 11 & 32 are + 5v and 12 & 31 are grounds. Don't forget to turn the power off before putting the chip back in. Possibly a electrolytic capacitor is in backwards?

Did your PCB's ever work? Maybe there's a short or shorts on the board. Check all of the pins on the 877 for shorts to +V and to ground.

I guess maybe it's Miller time! Sit back or walk away for the night and get a good night's sleep and try fresh again tomorrow. We've all been there! It's not a pretty site.

I know this is no consolation but it does help to walk away some time.

BobK