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HP CP1515n Color Calibration

Status: unbekannt

Beschreibung Fix Color Calibration of HP CP 1515n Printer
Autor: omicron
Version 1.0
PayPal Spenden für HPCLJCP1510Repair


The objective of this project is to fix a HP LaserJet CP 1510 Series printer having color calibration issues.

Short version


  • Color calibration of a HP Color LaserJet 1510 Series Printer (e.g. CP 1515n) is not working correctly (see top left part of image)
  • All attempts to fix the problem otherwise have failed:
    • Update to latest firmware
    • Repeated calibration (> 3 times)
    • NVRAM reset
    • Reset to Factory defaults from menu
  • The following other attempts were not done:
    • Replace the ITB assembly (cost reasons)
    • Buy set of original HP toner (cost reasons)


  • Print diagnostics page using the printer menu (for later comparison).
  • Get the service manual (Google for "HP Color Laserjet CP1215 CP1515 CP1518 Service Manual")
  • Follow the instructions for removing the Intermediate Transfer Belt (ITB)
  • Turn the ITB assembly upside down
  • Find the two small PCBs where the wires end
  • Take a photo of the positions of all 3 trimmer (labelled VR1, VR1 and VR2 on the two PCBs)
  • Find the trimmer labelled VR1 on the right of the two PCBs (the board with 2 trimmers on it). Example:
  • Turn VR1 clockwise about 90 degrees (other angles could work, too: Try it out!). Example:
  • Follow the instructions of the service manual for re-installing the ITB assembly
  • Connect printer to power
  • Start a color calibration
  • Print diagnostics page and compare with diagnostics page before the fix
  • Done (or further experiments needed - see notes)


  • This fix will certainly break warranty. Hence, only do it with printers being out of warranty!
  • The fix proved to work for a single CP1515n printer. It may have to be modified for other instances.
  • If changing VR1 on right PCB does not solve the problem, try the other trimmers (But always remember the original state!)
  • When testing the effect of changing the trimmer, you only need to reassemble the following components
    • The ITB itself
    • The print-cartridge drawer stop
    • The Print-cartridge drawer
  • But (as always) be careful not to touch any live parts when the printer is connected to power!

Long Version

Note that, if nothing else is mentioned, after each change I started calibration (at least, but usually only) twice.

Unfortunately, the short version worked only once. When I changed VR1 (see above), I also tightened the screws of the ITB. Hence there was a chance, that not the change of the trimmer led to success but the tightening of the screws. Hence, I changed back the trimmer to its original position and reassembled the printer. Then, as expected, the calibration failed again. Now I changed again the trimmer position as mentioned above and again reassembled the printer. Unfortunately, it did not work this time: Even after 3 calibrations the "L-lines" in the diagnostic page crossed each other.

Because of the above experience, I then supected a mechanical problem. Hence, I tightened the screws again. This time I used a special torque screwdriver and tightened all screws of the ITB module (which I could reach) with 1 Nm. Unfortunately, this did not help either.

My next attempt consisted of 4 things (I was quite in despair):

  • I temporarily dismounted the front top part of the ITB (see TODO) and remounted it afterwards without doing any real change.
  • I dismounted the two coil springs which seem to tighten the belt and stretched them with two pairs of pliers - for the purpose of increasing the spring stiffness (in a very amateurish way)
  • I again turned all 3 trimmers in the exact position where the calibration initially worked
  • I dismounted the 2 PCBs and removed the plastic covers covering the component side and cleaned them (for details see below)

After reassembling everything again, it worked again.

Now I again wanted to know, which change was the successful one (i. e. was it the cleaning of the PCB or some mechanical change), I turned the trimmer back to its original position. Now the calibration failed again. But after carefully turning the trimmer again into its known-working position, calibation was successful again.

Finally, I did some sensitivity analysis of the calibation working or not for various trimmer positions. As it turned out, I obviouly initially hit the correct trimmer position of VR1 by chance: The trimmer position must be in a range of about +/- 5-10 degrees to be optimal, i. e. leading to a correct calibration!