Me or Mooer?

[bool]

I did write to their service desk and describe the issue.  Their response indicated there was nothing I could do.

That's what you get for being nice.

[Rob Strand]

I did write to their service desk and describe the issue.  Their response indicated there was nothing I
could do.

That's nuts.  From what I can see not everyone experiences the detuning problem.  That would point to manufacturing issues, design issues, and/or faults.   It also means there must be a reason for it and if there's a reason it can be fixed!   

[Mark Hammer]

If I had spent good money, I would be upset.  But like I said at the time to the guy I paid $10 for it, "If it doesn't work right, I can always cannibalize it for the enclosure".

[Rob Strand]

If I had spent good money, I would be upset.  But like I said at the time to the guy I paid $10 for it, "If it doesn't work right, I can always cannibalize it for the enclosure".

If it has a crystal (or resonator) maybe you can check the oscillator frequency.  Measure at the oscillator output, which could be on the microcontroller, and not on the crystal.  To be honest I don't know why the pitch it would depend on the crystal but you never know.

[toneman]

I know this might sound crazy, but look at the bottom of the pcb (the top too as i assume it's doublesided)

Look for cold solder connections, lots of excess flux, etc.

Could be a memory problem. One bad bit can spoil the whole word.   

I use a small xacto knife to clean between the ic pads and traces.

Then clean everything with isopropanol. Everything should be shiney