Just FYI.

Got the CNC4PC C10 board, notice a lot of flux still on the bottom of the board. Cleaned with flux remover, then noticed two solder joint that were badly soldered, in fact one was a cold solder joint. Anyways just used my soldering iron and fixed it.

But having a lot flux paste on the bottom of the board can cause issues, I have built hardware devices where they will fail if I leave flux paste on them.

Flux is always bad to leave but I've seen worse. I once bought a cheap wired telephone to use as a backup in case of a power failure as none of my cordless would work without power. I brought it home and tested it. Everything was fine so I wrapped it up and stored it in with me emergency stuff. About a year later, I needed it but it would not work. I had to use cell phones. After the power came back, I was going to toss it but decided to open it up. I found a lot of some kind of flux on most of the connections and a piece of springy folded metal under a large cap. This capacitor had been badly soldered and when the joint failed, the piece of metal pushed the capacitor up and broke the connection. I took out the piece of metal and soldered the capacitor back in and the thing worked again.
Talk about engineered to fail...

My c11 went up in small flames last week:( Got another one yesterday, 10amp solid relay not working :(


-Jason

My c11 went up in small flames last week:( Got another one yesterday, 10amp solid relay not working :(


-Jason

I would take a look at all the solder joints under your board, and use an soldering iron to clean any solder points that don't look good, i.e. like they might not be making proper contact.

Also if you got lots of flux paste on the board, go to ratshack grab some flux cleaner (couldn't hurt.)