Designjet 1050C printhead rejected

[Antik_Drucker]

Hello everyone,

I'm having a problem with my HP Designjet 1050C. It's rejecting a new (original) printhead when I try to replace it. It says: "Check POS." The old printhead works fine. Unfortunately, I can't get in touch with HP directly. The contacts were slightly tarnished in the sealed packaging, but I've already carefully cleaned them. That didn't help. When I put the old HP printhead back in, it's recognized (it wasn't printing properly anymore, hence the replacement). So, it can't be the contacts on the printer. Does anyone have any ideas on how I can get the printer to accept the printhead, or anything else I could try? (Besides buying a new one, which aren't exactly cheap.)

Thanks in advance for your suggestions!

__________________________

Moin Community,

Ich habe bei meinem HP-Designjet 1050C das Problem, das ein neuer (original) Druckkopf beim Austausch verweigert wird. Es heißt: "Pos Prüfen". Der vorherige Druckkopf wird angenommen. Bekomme leider keinen direkten Kontakt zu HP. Die Kontakte waren leider in der verschweißten Verpackung leicht angelaufen, aber diese habe ich auch schon vorsichtig gereinigt. Hat leider nichts gebracht. Den vorhigerigen HP Druckkopf wieder eingesetzt, wird diese erkannt (Druckt nicht mehr ordentlich, daher der Tausch). Die Kontakte am Drucker können es also demnach nicht sein. Hat jemand eine Idee, wie ich den Druckkopf im Drucker akzeptiert bekomme oder sonst tun könnte? (außer einen neuen kaufen, sind ja auch nicht billig)

Vielen Dank schonmal für eure Ideen

[Qsaifoddin]

Hi @Antik_Drucker 

On the HP Designjet 1050C, the message “Check POS” means the printer cannot read the Printhead Orientation Sensor for that specific printhead slot. Since your old printhead is detected but the new one is rejected, the issue is most likely with the new printhead itself, not the printer.

Here are the steps you can try:

1. Verify the printhead type
Make sure the replacement printhead is the correct model for the Designjet 1050C. Even small revisions of the wrong part number will trigger “Check POS.”

2. Inspect the printhead’s chip area
You already cleaned the contacts, which is good. Check the rear chip area for oxidation, scratches, or a bent alignment tab. The 1050C is very sensitive to alignment.

3. Reseat and lock the printhead firmly
If the printhead is not fully seated or the latch is slightly loose, the printer cannot read the POS sensor.

4. Power-cycle the printer
Turn the printer off → unplug for 60 seconds → reconnect and try the new printhead again.

5. Try another printhead if possible
Even original OEM printheads can sometimes be defective—especially old-stock units.
If the old printhead works instantly but the new one consistently gives “Check POS,” the new printhead is most likely faulty.

Because the Designjet 1050C is a legacy model, HP no longer provides direct repair support, so testing with a second new printhead is often the only practical way to confirm the issue.