Mysterious null results on a single monitored branch circuit

Hi, Robert.

Reading this back to make sure I understand your suggestion, we want to take the input on a known working socket and feed it into the main board side of one of the non-working expansion inputs, thereby verifying that the main board paths are good.

That would involve a jumper from the pad next to the appropriate CT label on the main board to either CT7 or CT8s expansion input on the flip side of the board, as annotated below.

Do I have that right? I just want to make sure I get this correct. I’m getting a bit fatigued with working on this project and don’t want to rush in and make things worse.

I was searching for those a while back myself. I believe these are the sketches for the main and expansion boards.

It looks as if you’re right (I can rarely find anything on Github - it’s a more of a badger’s sett than a rabbit-hole).

I’ll get hold of those and load them into KiCad.

Correct. It’s what I did with the emonTx4 before I got the expansion board, to prove the library and sketch were doing as they ought.

No - the end of the protection diode - but your “D2” etc isn’t where the drawing says! You need the non-earthy end of those diodes D1 - D6, in the left-hand block of the schematic: the place labelled “CT1” etc.

And the pin you’ve pointed to on the annotated image is actually Vrefa - CT7 is at the other end.

CT8 is 2nd from the left, hopefully this image clarifies:

This pin on your CT8 looks a bit dodgy:

and also this one that relates to CT7

Please accept my apologies for this, we would be happy to send a replacement if you do not wish to solder these or if after soldering there is still an issue. This shouldn’t have been dispatched with these issues!

Thanks, Trystan! I’m pretty naff when it come to soldering. I’ve attempted to resolder both those points with no effect. I’ll take this over to OEM shop email.

1 Like

For any future readers on this thread, a replacement main board and expansion board from the shop has corrected this problem. All CTs seem to be working so far. I’m hoping to take the old boards and try to figure out what was off with these when my troubleshooting and soldering skills improve.