OpenSprinkler Forums Hardware Questions DIY Kit Assembly Questions Trouble powering 1.42u with 24vac Re: Re: Trouble powering 1.42u with 24vac

#24531

Ray
Keymaster

Hmm, that’s rather strange. I’ve never seen such a symptom before. 3.8V Vcc is definitely strange. It’s still within the mcu’s spec, so the mcu should be up running. But it’s certainly not normal (should be between 3.2V to 3.4V). I can’t think of any reason for the abnormal Vcc voltage. Assuming the MCP1702-33 is working (the chance of it being defective is very small), the only thing I could think of would be the capacitors C2 and C3. If these capacitors are not soldered reliably, or if you accidentally soldered the 10uF capacitor onto the position of 220uF, it may cause the voltage to be abnormal.