I recently bought a pen in a kit called the Presto kit. It was only $20 so it’s pretty cheap. The problem with it is the charger stays green but when I screw in the pen to charge, it stays a solid red color. I’ve tinkered with the contact point of the pen but nothing has changed, the pen still won’t charge. I don’t know if it is just a dud or it is something I can fix. Please let me know.