I have Hp officejet pro 8500 all in one a 909g printer. Printer goes device cheking and printhead cartridge mode when I switch on and off. Please help him. When I switch on printer is going to ready mode then after few seconds device ching and printhead cleaning mode for two minutes and then coming to normal mode. during this process first time when it is on ready mode there was an error mark on control display later after going through the process of device ching and printhead cleaning. The error will not be shown. Please help. I am wasting lot of ink. Regards

Unplug the printer and wait 20 minutes and then re-plug.

Look on you tube for a video on how to clean the print head.

Power on printer and soak up spilled ink with towels. Next we suggest you remove PRINTHEAD from printer and inspect for damage to contact pin(s) on the INSIDE OF THE PRINTHEAD ASSEMBLY. Please refer to printhead removal procedure below for reference (HP Officejet PRO 8600 Printhead Removal & Replacement Procedure):
http://h10025.www1.hp.com/ewfrf/wc/document?cc=us&lc=en&dlc=en&docname=c02871867

NOTE: To gain access to the service menus and advance printer reset procedures (and service tests) for the HP Officejet Pro 8600, 8610, 8620 or 8630 series printers please refer to our HP Diagnostics document at the following link:

Advanced HP Printer Diagnostics (i.e. printer self tests, etc.): http://inkjet411.com/?page_id=1813

Please note that if you choose to refill your ink cartridges with Costco/Frys, etc., the refill comes with a new chip so the ink level monitoring will be reset and function like a brand new HP OEM ink cartridge. We provide professional HP 950/951 ink cartridge refilling services in multiple countries and at multiple retail outlets:

INK REFILL SERVICES:
Costco USA (462 stores): http://www.costcoinkjetrefill.com
Costco Canada (57 stores, more coming soon): http://www.ca.costcoinkjetrefill.com
Costco Mexico (35 stores): http://es.costcoinkjetrefill.com/
Fry's Electronics (34 stores): http://www.frys.com/ads/page51
Best Buy Canada (13 stores): www.geeksquad.ca/inkrefill/
Micro Center (8 stores): http://www.microcenter.com/site/content/refill-service.aspx
9 Major Universities in USA & Canada
Ink Cartridge Refill Store Map Locator: http://www.go2ris.com/

Our network of retailers stand behind the product and performance - guaranteed. Customers who have questions regarding the use of refilled ink cartridges can visit http://www.inkjet411.com or contact us directly at [email protected]

Alternatively, if you need to purchase a new ink cartridge(s) and are trying to cut costs, we suggest you try a remanufactured ink cartridge from http://www.inkplicity.com/ as their ink cartridges typically have the lowest cost in the USA, have a high reliability rating, come with a 1-year warranty and provide free shipping for all orders above $20.

-Thank you

maybe just calibration printer , to take new cartridge printhead ,or power cord not plug well

Sir

Please See Below You Tube Link URL To Fix Your HP Printer Error

How to Fix Failed Alignment HP Officejet Pro 8500 Premier All in One...

Hi there,
You cannot install HP 940 Cartriges for Officejet Pro L7650 as they are not compatible and the mechanism is different for both the cartridges,
In your printer, the HP 88 fits on the left bottom corner of the printer and the HP 940 cartridges are mounted on the Printhead inside the printer on HP Officejet 6500 AIO.
Regards,Suhail

this website shows how to replace the printheads
this should fixya up
http://h20000.www2.hp.com/bizsupport/TechSupport/Document.jsp?lang=en&cc=us&taskId=110&prodSeriesId=3752454&prodTypeId=18972&objectID=c01623635

Try Cleaning the Cartridges manually and automatically.
For the cartridge clean it with a damp lint free cloth and also for the printheads wher eyour gonna be inserting the cartridges.
Follow these steps do do the automatic aligning and cleaning:
Click Start and then go to Printers and Faxes (XP), Printers(Vista), Devices and Printers(Win 7)
1. Right Click on your printer Icon 2. Go to Printing Preferences 3. Click the Features Tab 4. At the bottom of the window you will see Printer Services or Device Services. Click on it. 5. Choose Align Printheads on the list.

For Cleaning the Printheads, Instead of choosing Align Printer choose Clean Printheads.
I hope this helped.
Try Printing Again. I hope I was able to solve your problem. :)

I have the same problem. I replaced both printhead cartidges. The MC light stopped blinking, but the KY light kept blinking. I thought it was a faulty new KY ink cartridge. So I returned that cartridge and got a new one. Still the same issue. I called hp and they said the print head is bad now and all they focused on was trying to sell me a new printer. UG! I also heard wiping off the printhead with a dry cloth may help. Did you get yours to wokr?

Have you tried to replace the black/yellow printhead? This is not the same as the ink cartridges, but it is located in the compartment under and to the right of the scanner lid.
Here is HP's link.
It looks like this...