Kyocera m8124 faded prints

[RonnieR]

I serviced a kyocera M8124 that all 4 colours were very faded. Drum refreshes and a firmware update didn't solve it but running several Dev Cleanings brought it back to normal.
They called again the following week with black only faded, and Dev cleanings didn't work, but reseating the black dev and drum brought it back immediatley. They called back the next week with the same problem so I talked the customer through reseating the dev and drum over the phone, but no luck.
Any thoughts?

[Dark Helmet]

Kyocera toner or knock off?
How old are the drum and dv units?
Can you get a U089 sample?

M8124 manual says it's U115 for Toner / DV ratio.
On the big machines U155 displays toner / DV ratio. Target is 0
Positive number is high toner, negative is low toner.
If you are seeing large negative numbers that would indicate a depleted DV unit.

Manual says you can reset U140 values to default and run U140 again.

[richs]

I can send a manual if you want.

[newdente.gianluca]

Did you fix the problem? i have same problem.

[Ropariva]

I’ve had a few HVT failures on these with this symptom.

[newdente.gianluca]

oday I had the opportunity to mount all the drums and DVs on a working machine, after an initial calibration cycle that the machine does automatically I tried to print and it prints well, I put all the units back into the original machine and now it prints well but I don't think it will last.