Color Laserjet 3800DN: color misaligned

[groovy]

Hi all,
here lies a color 3800. three months ago asked for a new fuser, after replacement the yellow color is misaligned, it prints about 4/5mm higher than the other colors.
All toners inside are original, also i tried to change them (original and brand new) and the problem is still here.
Tried to clean the lsu assembly with no luck, same result.
In the service manual is asked to clean the color misregistration sensor but i cannot figure out where is it (maybe in the transfer belt assembly?)
I'm thinking to not replace the hvps board, because it is selling at about the price of a new printer.
Performed so much calibration and nothing happened.
Also in the event log there are various CPR sensor out of range errors.
Any ideas?
Thank you so much.
Luigi - Digitalix

[theengel]

Re: Color Laserjet 3800DN: color misaligned

I would replace the transfer before the HVPS.

[groovy]

Re: Color Laserjet 3800DN: color misaligned

Hi again and thank you for the quick reply.
Why i need to replace the transfer belt? It is not worn, all the color looks pretty good.

[theengel]

Re: Color Laserjet 3800DN: color misaligned

The color registration sensor is in the transfer unit. Generally, you would do things in this order:

Calibrate
Full Calibrate
NVRAM dump
Full Calibrate again
replace toner ctg.
replace ITB (transfer unit)

[theengel]

Re: Color Laserjet 3800DN: color misaligned

I forgot: In some of the machines (usually the 4700 series) NVRAM holds on to certain values and calibrating doesn't help. You have to do a nvram initialization in order to get the calibration to work. But that's usually linked with color density and not the alignment. In your case, I would bet on either the toner cartridge or on the transfer unit.

[groovy]

Re: Color Laserjet 3800DN: color misaligned

I forgot also i did a cold reset (this printer doesn't have nvram initialization).

[faxman28]

Re: Color Laserjet 3800DN: color misaligned

from 3800 service manual


NVRAM initialization
CAUTION: All HP Jetdirect settings are also reset. Be sure to print a configuration page before
performing an NVRAM initialization. Make note of the IP address that is listed on the Jetdirect
configuration page. You need to restore the IP address after performing an NVRAM initialization.
Performing an NVRAM initialization resets the following settings and information:
● All menu settings are reset to factory default values.
● All localization settings, including language and country/region, are reset.
After performing an NVRAM initialization, reconfigure any computers that print to this printer so that the
computers can recognize the printer.
To perform an NVRAM initialization
1. Turn the printer off and then on.
2. When the printer begins its initialization sequence, press and hold "down arrow" until all LEDs are lit.
3. Press "up arrow" one time, and then press Menu.
4. Press "down arrow" until NVRAM INIT appears, and then press .

have had this happen with generic cartridges,

HP recommendations for one color plane out of line: check toner cart, laser unit, drive system, also make sure firmware is up to date , last fw was in 2013.

perform cartridge check mode , swap yellow with magenta does problem stay with yellow cart or with the cartridge position, if it is position, then maybe drive system or laser. also dc controller could be defective.