TASKalfa 7551ci colors go light after a few hundred copies

[logrady2331]

Hello all,
I have a TASKalfa 7551ci with 38k on it. Yes, not a typo, 38,000 total. We installed it last week and two days later the customer calls and says all three colors are super light/faded. We weren't sure of the health of the developers so we ordered the color MA kit and also replaced the t-belt while we were at it. It set up just like it should with the new PM kit and t-belt. Two days later our tech went to the customer for a follow up and all three colors are super light AGAIN. It never asks for color toner and to my knowledge doesn't present any error codes. Any thoughts? I am leaning toward main or engine pcb but wanted to see of anyone has seen it before. Thanks in advance for any suggestions.

[blackcat4866]

What simulations did you do?
Do you have any samples? Try something like this:

[logrady2331]

Hi Blackcat,
Thanks for the response. We cleaned the ID sensors of course, ran 140, and 119, 465,469 and 410. Color density returns to normal after dev refresh and calibration in user tools. It never asks for toner. Black is fine, never goes light. It is plain to see it isn't adding toner as CQ comes back after a refresh. Dev units are brand new so I am ruling out toner sensors.

[logrady2331]

Blackcat, My senior tech tells me ALL colors are affected. Sorry about that. I know that changes the approach. He can run sim 131 and the voltages/toner sensor levels return to normal. No error codes at all. Never asks for toner.

[dalewb74]

optics are clean? genuine kyocera parts?

[PrintWhisperer]

Check the customer power for sags and Neutral to Ground faults.

Even though it comes with 2 Nema 5-15R power cords, this machine requires a DEDICATED 20 AMP circuit.

The hi-volume frames are power hungry and don't like to share.

If the power droops during a calibration it could throw it off like that.

[blackcat4866]

... and those samples? =^..^=

[BillyCarpenter]

When we experience the image quality like high back ground or lower density issue please check the history of calibration


How to check?Go to the simulation U486 and you can find the Hex data at “Speed Adjustment” .In this case it is 00FFFC. This can explain the recent calibration result. Type in this value to the normal windows calculator ( Usage/ scientifical)




This 1111111111111100 shows you the history of
calibration result.

“1” is succeed. “0” is error. So in this case last
two calibration resulted in error.
If calibration error found, contaminated ID sensor
OR significant light density of toner patch during
calibration is possible.
For contaminated ID sensor error, we try manual
ID sensor cleaning first of all.

[BillyCarpenter]

Oops. The above procedure was for a different model. This is for your model.

Check U468 V-Correction value.
Good value/ sucessfully running last 16
calibrations = 65535
Decimal: 65535
Binary: 1111.1111.1111.1111
(each “1“ = sucessfully calibration)
For checking, use scientifical setting from calculator
Additional you can check Eventlog for
C7601-front ID sensor error
C7602-rear ID sensor error
(C76xx won`t shown on operation screen)
For checking surface from Transferbelt
U465/ Stress must be between
2200 - 2900

KYO_OEM taught me how to check the last 16 calibrations to see if they passed/failed.

[Ropariva]

Have you tried swapping K drum to M or C before a refresh to see if the issue moves with the drum?