Ultimate JV3 Diagnostic Challenge, open to any tech or other superpower

[Stripeman]

First off, yes, I do still run a couple JV3s....

My oldest machine is a 160s running 6 color config. I began having what appeared to be starvation issues. I noticed while printing 720x720 slow speed. I would begin to lose approximately 5 - 10 nozzles per pass, until pretty much, no print at all. A quick short clean restored printing. 720 x 720 high speed, seems ok, but will eventually drop black and light cyan (outermost printheads) but the other colors are good. I have some donor machines and have replaced: mainboard, slider(new), each printhead (1 at a time), power supply, both small IO boards, encoder sensor, encoder strip, printhead cables, mainboard to slider cables. I just cant figure this one out. Another quirk for informational purposes: When I swapped the mainboard, of course, alignment and head ID had to be updated. When printing x direction marks, it makes it about halfway through and begins dropping nozzles. Im pretty sure the printhead holds enough ink to get through this print, so it seems like a voltage issue. I did swap the power supply, but have not specifically checked the connections for actual voltage.

Any ideas would be appreciated..... Im getting a replacement for the machine, but its a battle of wills at this point.

 

[Solventinkjet]

I didn't see anything about dampers, cap tops or pumps in your description. Have you changed any of those? Ink starvation is almost always due to one of those items failing. Especially with new heads installed. I would start at the dampers including the o-rings and maybe the capping station if it is older than a year. Flush the pumps with cleaning solution to make sure they are not clogged as well.

 

[Stripeman]

The pumps are relatively new (3-4 months old) Dampers are new too. It only does this when I run slow speed. I can go into #test menu and print full test patterns on each head and it puts the ink down fine. I think if I were truly having a starvation issue, it would not be able to print at that ink volume at all. Im telling you, its really freaky what this thing is doing. 702x720 unidirectional, 8 pass, slow speed=FAIL, 720x720, bidirectional, 8 pass, high speed, ok with minor dropout occasionally.

I didn't see anything about dampers, cap tops or pumps in your description. Have you changed any of those? Ink starvation is almost always due to one of those items failing. Especially with new heads installed. I would start at the dampers including the o-rings and maybe the capping station if it is older than a year. Flush the pumps with cleaning solution to make sure they are not clogged as well.

 

[SightLine]

OEM pumps or aftermarket pumps? If aftermarket, check them close. In the past 12 years or so I have tried to be cheap at least 10 times on pumps and all but one aftermarket pump lasted less than a year. The one that went over a year only did so by a few months. Yet an original Mimaki pump seems to go for 3 to 5 years no problem....

Either way check for leaks at the joints in the lines, pumps, lines to the cap tops, dampers, etc.

 

[Stripeman]

Im pretty sure these are factory, Ive been bitten by china pumps before.

As noted previously, I can print high speed, not slow.

OEM pumps or aftermarket pumps? If aftermarket, check them close. In the past 12 years or so I have tried to be cheap at least 10 times on pumps and all but one aftermarket pump lasted less than a year. The one that went over a year only did so by a few months. Yet an original Mimaki pump seems to go for 3 to 5 years no problem....

Either way check for leaks at the joints in the lines, pumps, lines to the cap tops, dampers, etc.