Troubleshooting anything is a process of elimination. Since you are convinced that it's not the juice, the cartos, or the priming, then it must be the VAMO. However, you cannot reach that point conclusively unless you try your setup on another APV. If you don't have that problem on your backup APV, then you can conclude that it is the VAMO. If the same things happen on your backup APV, then it's not the VAMO, it's the cartos, the juice, the priming or some combination of those. These issues aren't that hard to figure out and it sounds like you've tried everything but a new battery. Only a new battery will allow you to be conclusive about your VAMO. Surely you have some other device to try out. Like others have said, it's not hard for me to believe that you could get a number of bad cartos. Sometimes the production methods change and mess up the cartos for a long period of time. Boge had this problem six months ago and produced bad cartos for several months. This is well documented. Good luck to you.