New Heatermeter Build - power and voltage issues.



New member
Hi there. new to the forum but have been using HM for probably 8 yrs... running a 4.1. I am working on building a new 4.3 and have completed all the steps but am getting some odd behaviors. Note that it is not yet hooked up to a RPi
1.) When powering on, sometimes i'll get blower activity but it starts and fades. when pressing on the ATMEGA chip, sometimes it'll kick back on and sometimes not.
2.) I get absolutely no voltage reading on LE1 when it should be reading 3.3V at least according to the schematic on the wiki.
3.) when connecting the LCD, it will sometimes power up and sometimes not. If it does power up, it'll be a backlit display but no text is visible. Then it loses power and cuts off entirely.

I have checked all solder points and everything, at least to my eyes, looks fine. I'd love any thoughts on what specifically to check. happy to attach photos of the boards if it'll help.

Thank you and please help!!



TVWBB Diamond Member
You note the new HM is not attached to the rPi.... did you initially connect the new HM to the rPi so the firmware could be loaded on the ATMEGA? If not then your HM is a blank slate, no operating system... Need to program the SD card and connect the rPi to the HM and let if boot and flash the ATMEGA.
If you've done that then you have something else going on, in which case photo's are always helpful.


New member
Hi and thanks for the reply. I found some issues on the baseboard so I rebuilt it. Reflashed and everything seems to be working just fine now! The LCD seems a bit inconsistent. would welcome thoughts on that. As you'll see from the images, the "M" in Manual and the "N" in No do not display properly but the pixels themselves are clearly active as evidenced by other displays.


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