TASKalfa 4052ci Error codes C7901, C7903, C7904, C7911

[kyove]

Hi Guys,

I have a TASKalfa 4052ci who gives these error codes in the last month:
C7901, C7903, C7904, C7911.
The first and the last in this morning. Lately things are going badly...
A couple of times error C7620.

Service manual talks about dirty in contacts but I don't think it's my case. A poor contact on a drum must give multiple errors on the same drum.
Here codes are rolling quickly!

Someone has seen these errors?
How to resolve?

Some little printer statistics:
About 150k prints, 118k BW and 32k color
Firmware updated!

Thank you in advance,
Kyove

[copiertec]

Service manual does not mention dirty contacts, but it does mention to make sure all connectors are connected to start with. Being the codes are all drum and developer related, first, I would make sure you are receiving proper voltage and ground to the mfp, 2) which you already have done- update the firmware. If these do not fix your issue you could try installing another black drum/ developing unit and see if those codes are corrected. If they are not corrected after installing those parts, you are looking at board issues particularly the engine pwb.

[KYO_OEM]

1. step
Check serialnumbers from DK units by U117 and/ or DV serialnumbers by U984
Mostly you`ll see same serialnumber for 2 or more units.
Now you must find broken unit by using well working other DK/ DV unit.
2. step
reconnect YC17 on feed image pwb, sometimes bad connections on pin B17 - B20/ missing 3,3V power supply for Eeprom communication.
3. step
also check YC1 on drum/ developer relay pwb pin 1-6