HP LaserJet Pro 400 color Printer M451 series - Manual (Page 161)

Recommended action
Turn the product power off, wait at least 30 seconds, and then turn the product power on and wait for
it to initialize.
If you are using a surge protector, remove it. Plug the product directly into the wall socket. Turn the
product power on.
If the message persists, contact HP support.
79 Service error Turn off then on
Description
An incompatible DIMM is installed.
Recommended action
1. Turn the product power off.
2. Install a DIMM that the product supports.
3. Turn the product on.
If the message persists, contact HP support.
Black cartridge low
Description
The print cartridge is nearing the end of its useful life.
Recommended action
Printing can continue, but consider having a replacement supply on hand.
Black in wrong position
Description
The print cartridge is installed in the incorrect slot.
Recommended action
Make sure that each print cartridge is installed in the correct slot. From front to back, the print
cartridges are installed in this order: black, cyan, magenta, and yellow.
Black very low
Description
The print cartridge is at the end of its useful life. A customer configurable option on this product is
"Prompt to Remind Me in 100 pages, 200 pages, 300 pages, or never." This option is provided as a
customer convenience and is not an indication these pages will have acceptable print quality.
ENWW Interpret control panel messages 143