Can you please send me a photo or two showing the VLM cart that you had difficulty priming?
As per our written instructions, we recommend priming by using the priming tip attached to the syringe tip, inserted thru the exit valve with the cartridge sitting upright.
Let me give you some background info, to clarify why there are two different priming procedures for the 3800/3880 carts. When we first got these carts, the manufacturer's (limited) instructions said to prime the carts thru the exit channel side port (as demonstrated in our video), which worked pretty well. Around the same time, we were testing many other carts (we are constantly researching + testing- to ensure we have the best available products on the market), and have always known about the importance of priming carts before installing for the best ink flow. We discovered the priming tips that go on the end of a slip-tip syringe while working with other model carts, and tested this tool/procedure on the 38xx carts as well. We feel this priming tool/method is easier, quicker, and has less chance of a possible ink mess- so updated the written instructions and began including the priming tips with the carts. We have not yet had time to update our video, and although it can be a bit confusing that our video and written instructions don't have the same priming procedure, both procedures do work well and either can be used, but we do plan to (as soon as we have the time) update the video to match the written instructions priming procedure.
Please let me know so I can help.
Thanks and best regards~ Dana