View Single Post
  #7  
Old 10-05-2015, 10:56 PM
NoPegs's Avatar
NoPegs NoPegs is offline
The glass is -3dB.
 
Join Date: Mar 2014
Location: Amish Country PA.
Posts: 376
Go through the ICs and examine the RST pins, there's usually an R/C network attached to reset on powerup. One of the components might not be working correctly. You can troubleshoot this by actively pushing the pin high or low depending on the active state it is expecting. (See datasheet.) Also make sure the main oscillator is running if its a micro-controller system. My first instinct was "Sounds like it isn't getting the initial power on reset it needs." Hook it up to a scope and check the risetime of the VCC line? Ideally its a steep and rapid rise, but if it looks drawn out (dozens of ms) check the PSU caps. All else fails, start probing around the IC pins with the scope or a logic probe and look for any signs of activity and go from there.
Reply With Quote