Hi, I was wondering if I could upgrade the battery in the GMC-320+. I know it already has great battery life but if I 3d printed a case extension could I upgrade it. Also is it possible replace the mini usb port with a micro usb port for charging. I have one mini usb cable compared to the hundred micro usb cables. Just thought it would be a cool upgrade. Also if I am making an external probe for my gmc320 do I need to raise the tube voltage for the BNC cable that I am using. the cable has a resistance of 75ohms.
Can't give much advice on the extended battery/USB, but, yes, you can use the BNC cable. The 75 Ohms refers to Impedance and wont load down the tube voltage, but keep the length less that 4 feet for best results. I'm using an SBT-11 tube on a 3 foot BNC terminated cable on the GMC320 and it works fine. Great sensitivity.