I have an HPIL Thinkjet printer that hasn't worked the last couple of times I tried it. It goes through all the motions, but does not put any marks on the paper at all. I don't think it's the ink cartridges I tried, since they would put out fresh ink on the print head when poked gently with a big paper clip in the hole in the back. Is there something that commonly goes wrong with these printers? For the last several years, I've just been using my Epson printer with my HP-41 and 71, but it would be nice to be able to use old programs that print hi-res graphs, without re-writing them for the different Epson graphics commands and data format.
BTW, the original battery pack went out soon after I got the printer. When I found out how much they wanted for a new battery pack, I made myself a 7.8V power supply instead, which cost me fifty cents. I had everything I needed except one diode, and that diode was fifty cents. Before completing the power supply, I even tried the printer on a 9V alkaline battery. That worked fine, but the battery only lasted about six pages before becoming unable to deliver the current peaks. The battery was still almost new to other pieces of equipment that had low current demand.