Canon iR ADV C72xx Error E0020-01A0

[MrB]

Can anyone help.
Having a right nightmare with the above with this error code

If the device is used on black only, No problems
Once you try and copy/print any colour it throws up E0020-01A0

I have been given this after another engineer couldn't fix this.

All started with an E0012 (Not sure what sub code), followed be E0020 on the magenta side
The other engineer replaced the Magents Deve & Drum, and now it stuck with this E0020-01A0

So far we have changed the Yellow drum and deve, Cleaned and replaced the Patch Sensor Assy

Backed up and cleared the DC Con, and restored it
Replaced the DC CON.
Cleared the main controller in case but still no effect.

We have now found that the DENS SGNL-Y & SGNL-M are stuck on "1" unlike C & K that are showing a value around 120

Does anyone have ANY ideas.... All be greatful

[Canuck]

The E12 subcode would be helpful. Your yellow density reading is missing basically. Did the yellow dev get depleted? I believe that density measurement is taken in the dev housing, during ATR. The problem might not be with just yellow...could be something common with Y and M, just that yellow is first color in process so it will croak when it doesn't get past yellow. Might need a Main Con 2