Do you have good decoupling capacitors very close to the PIC ? Try a 100nF capacitor directly across the PIC power pins. Dom ----- Original Message ----- From: "Estevan" To: "Microcontroller discussion list - Public." Sent: Tuesday, June 17, 2008 6:13 AM Subject: [EE] AC to DC Conversion = PIC problem? > Folks, >   > I have a strange problem here. I have an AC to DC converter circuit that > is powering a PIC16F873A that is connected to a 2x16 LCD. When the unit is > connected to the AC line (US 60Hz) the PIC does not begin it's program > (LCD has nothing but bars). The +5V regulator has a solid +5V, but as soon > as I unplug the AC cord the program begins to run (large filter cap) until > the filter cap discharges (LCD displays prompt). Could this be from the > 60Hz noise causing problems or ... ? Any ideas, recommendations or "magic" > pointers out there? >   > Thanks ahead of time! >   > Estevan. > > > > > -- > http://www.piclist.com PIC/SX FAQ & list archive > View/change your membership options at > http://mailman.mit.edu/mailman/listinfo/piclist > -------------------------------------------------------------------------------- No virus found in this incoming message. Checked by AVG. Version: 8.0.100 / Virus Database: 270.3.0/1503 - Release Date: 14/06/2008 18:02 -- http://www.piclist.com PIC/SX FAQ & list archive View/change your membership options at http://mailman.mit.edu/mailman/listinfo/piclist