I have an old but almost unused DJ 4 P and when I shelled out for the cartridge, I was concerned that it would be money down the drain. All set to go...and it didn't.
Although it did report a code, the mean

s at a local HP place were not about to decode it for me. Anyway, I found out that it was nothing more than A4 V Letter. Set that up and it was perfect. Rolls Royce of a machine.
But get it wrong, and the darn thing just sits there with its arms folded and pouts.