Printhead depositi vertical lines randomly after almost full replacement of most parts Z6200 DJ

[JPB257]

Hello, all. I am working with a tech who is in contact with a company that is doing their best to resolve the problem, we are at a dead end.  

The printer, a  DesignJet HP Z6200 60" was going fine in it's tenth year (estimated), discovered an over flow of ink dripping on to prints. Called Repair and they cam to replace ink system. Because of a broken Bag error and a 23:10 error. we replaced the pumps. There was a new a carriage (with PCB) installed as well as the hard drive.  Before all the repairs the prints were perfect, just the carraige was full of ink.  Now we can't locate the source of the image. Yesterday we changed all the printheads.

The random (maybe not random) lines on the prints are only in the red and black colors. There is no way for us to know which print head it is. Also curiously the Printheads test print is perfect. Is that generated off the PCB? And all other prints from the print system? The lines happen on both internal prints and prints from the computer. 

Photos are attached. You will recognize the internal prints. of you line up the paper roll direction. you might correlate that the marks are occurring within a certain place each time. BUT one print is real bad and doesn't fit that pattern. 

I am at a school print shop so please don't reply with any "end of service" ... "replace it" comments, thats a waste of our time. This needs to work. We are so deep in repairs, My ink stock, and print heads, I should have just got a new machine, I realize that. This was not an error before the replacement. 

Some of our thoughts might be the data cable from the back to the PCB in the Carriage, Static interference (but all magnets in back are in the correct place shielding the correct cables, 

Looking forward to your collective experience. Diagnostic fine.Print direction to the right, printing on coated paper the lines don't bleed and show the whole length or ink depositied from one print head.Print direction to the rightPrint direction down. Internal PrintBoth internal prints, top is still in machine/cancelled. bottom is previous. line is same position (roughly)Bad print, that wasn't in that position. The top lines are fuzzy because of the paper, uncoated, wet from other ink/bleeding.Marks appearing on left of test printLatest, last night after returung original carriage back in machine.

[Repairatrooper]

I applaud the depth of detail in your post. However a model number would be appreciated.

[JPB257]

My apologies, stupid newbie mistake. Post is editted, and for the reply, it is a 60" DesignJet Z6200. 

I think we are close when we begin inspecting the Data Cable to the PCB, and maybe the encoder strip (which was 'cleaned' but might be worth a second look. 

Thanks for anything you can offer.