Replacement thermal sensor module

My PA-II sensor stopped transmitting suddenly a few days ago and upon examination, research, and a bit of disassembly it appears the thermal sensor module, GY-BME/P280, is damaged due to corrosion having devoured a tiny capacitor (circled in red).

Is this module (GY-BME/P280) available through Purpleair? If not, why not, I wonder?

I have located the exact device available online but worry that simple replacement may introduce calibration issues, or something. With the laser counters being available I am surprised the thermal sensor isn’t listed as well.

Anyone have experience or advice to share in this area?

Hi @David_Parkhurst; you can purchase a replacement BME280 by request. They cost $10 + shipping. If interested, please email us at with your full name, email address, and shipping address to create a quote.

The following link will take you to a video on completing the replacement process: Add BME680 to PA-II or PA-II-SD.mp4 - Google Drive.

The video will mention a BME680. However, the process is the same for the BME280.

Thanks for pointing me in the right direction. I got the part (and paid the postage!), installed it without a problem but still the PA-II isn’t working. The fans whirl and the red LED lights up but there is no sign of wifi, neither as an access point nor as a device connected to my network. The PurpleAir Utility (Win10) doesn’t see it at all, despite trying many different usb data cables and two different computers, and installing the special drivers. Perhaps this is a failed motherboard? The only visible issue was with the corroded capacitor on the BME280 which I assumed was the entire problem, otherwise it appears to be clean and in excellent condition.

I’m not sure what to try or do next. Any suggestions?