For more than a year now my GMC-320 plus is no longer counting. It comes on and the software works, but counts zero. It worked well for over a year after I bought it. Your advice will be highly appreciated.
Just throwing my thoughts out there. Perhaps the GM tube is broken, damaged? I have seen them on Ebay for ~$30 US. Might try contacting GQ Electronics directly firstname.lastname@example.org to see what they think.