pro c500 prints low quality !! (+pic)

[iust]

11995

hi

my prints have bad quality. ( please see shodows and gradients )

I adjust "auto gamma add." in OP mode correctly but "sensor printer" got E31 , I reset to factory value but it dont correct.

please help me .

[maccenterpc]

Sensor gamma value is incorrect. Try to find and set the previous value.

Clean the strip sensors that read the transfer belt.

Repeat the automatic gamma

[iust]

Sensor gamma value is incorrect. Try to find and set the previous value.

Clean the strip sensors that read the transfer belt.

Repeat the automatic gamma

where are strip sensors exactly ?

[RRodgers]

where are strip sensors exactly ? Right above the fuser.