OpenSprinkler Forums Hardware Questions OpenSprinkler Pi (OSPi) OSPi Ver 1.3 layout request Reply To: OSPi Ver 1.3 layout request



I am pretty sure the schematic is the same, despite the fact that the board layout is different. From the schematic you can tell that one end of the PTC fuse is connected to the positive pin of capacitor C2, the other end is connected to VIN (i.e. +5V).

You should also make sure to check the zener diode D3 and the RTC DS1307. The reason is that if there has been an overvoltage situation, D3 is likely burned and DS1307 is also likely damaged. So before you power on by 24VAC, use a multimeter to check the resistance between VIN-GND. That resistance should be at least 4.5 kilo-ohm. If it’s below that, some other components on the 5V line may have been shorted.