C6500 Gamma Sensor & Max Density Sensor Readings

[vickash]

Hi,

I'm working on a C6500 that hasn't been run in a few years. I suspect the gamma sensor is bad. It has the old registration assembly in it (pink dot), and when I run the maximum density sensor output check and the gamma sensor output check, both give values of 152. Am I right thinking those should be closer to 127?

The main symptom is that reds are coming out orange no matter how many adjustments or calibrations I do. Swapped out magenta corona and drum, transfer belt assembly and lower transfer roller to rule out. No changes. Didn't get around to swapping the developer yet.

I'll have access to a second (new version) registration assembly to swap and diagnose later this week, but was wondering if I'm on the right track.

Thanks in advance!

[orestesp]

Hi,

Here are the readings from my machine. Hope this helps.

Max. Density sensor: 119

Gamma sensor output:

Gamma color: 119
Gamma black: 120

[tulintron]

Hi,

I'm working on a C6500 that hasn't been run in a few years. I suspect the gamma sensor is bad. It has the old registration assembly in it (pink dot), and when I run the maximum density sensor output check and the gamma sensor output check, both give values of 152. Am I right thinking those should be closer to 127?

The main symptom is that reds are coming out orange no matter how many adjustments or calibrations I do. Swapped out magenta corona and drum, transfer belt assembly and lower transfer roller to rule out. No changes. Didn't get around to swapping the developer yet.

I'll have access to a second (new version) registration assembly to swap and diagnose later this week, but was wondering if I'm on the right track.

Thanks in advance!

Honestly, I can't say what the ideal value is. It seems specific to me. I've seen cases with different values and with the same result ok. also other cases with equal values and different results.I have already changed the values of the potentiometers on the plate and never reached the expected result.


but...


you can run Recall Standard Data in Process Adjustment and immediately run Test Pattern # 80.


if you get the red result, run the gamma and then test pattern 80 again. after adjustment, there was no red, bad sensor.

[vickash]

Thanks for the tips. Got a chance to swap the sensor plate out with the newer model one this morning. The first test print after initial startup adjustment was still orange. Then I did the "Automatic Gamma 0" adjustment under Drum Peculiarity and got a nice solid red.

I put the original back in, did "Automatic Gamma 0" again, and the test print was back to orange. The calibration values for all 4 colors were much lower (by about 200 each) with the old sensor, if that matters. Installing a new sensor looks like it will solve the problem, so I'm ordering that.

Honestly, I can't say what the ideal value is. It seems specific to me. I've seen cases with different values and with the same result ok. also other cases with equal values and different results.I have already changed the values of the potentiometers on the plate and never reached the expected result.


but...


you can run Recall Standard Data in Process Adjustment and immediately run Test Pattern # 80.


if you get the red result, run the gamma and then test pattern 80 again. after adjustment, there was no red, bad sensor.

Forgot to mention that I also tried recall standard data before I made this thread. Same result.