I have the MXA042 flame detector and I've had it working. Then unfortunatly the TR4 transister died and with help fro your support staff I sourced and replaced the failed tranistor. It then worked for another week. But now it has stopped detecting any flame. I am no longer am able to detect a voltage across the flame sensor probe points.

The transisters seem to check OK, if you have any suggestions what to look for or do I send it back for free repair under the 90day warranty.
https://www.thaikits.com/index.php/terms-of-sale.html

Please check all transistors and taking pictures of the circuit below and above then send to us. So that we may conduct a preliminary examination.

I have the same board. Everything was connected and working on a clean 12V supply. After 15 minutes of positive flame detection the board stopped detecting flame. I purchase the board through on of your venders but they are not being cooperative. I sent the board along with documentation of the test circuit back to them but no response. Now I'm out a board and no replacment. I purchased another board because I needed to get this project up and running. That board has run flawlessly for well over 48 hours. How can I obtain a replacement for the defective board?