Wanted to see if it is a general problem in 300E with buttons. Does it always take several pushes before getting response, or is there a problem with my unit? (For example switching between uSv/h - mR/h - CPM)
Seems like software would only monitor buttons at certain intervals of time, or CPU is just generally too busy to respond...
It is not very sensitive looks like. It may be the new keys. Just press harder and more to see if the situation improves. If not, then you can write to support@gqelectronicsllc.com for the warranty.