79 Service Error on Laserjet Pro 500 M570DN

[cityofcommerce]

Within a week of moving to a new location, two HP printers of the same model started showing "79 Service Error" and resetting themselves in an endless loop. This problem only occurs when the printer is plugged into our ethernet, but the printers need to be plugged into the network for our purposes.

There are several support articles on this website about this error code -- I have read them all and followed all of their recommended steps. The problem persists.

Here's a list of what I have tried:

- I went to every computer on the network and cleared the print queues of all pending print jobs

- I uninstalled the printers from all computers, and rebooted the computers

- I updated the firmware on both printers to the very latest version

- I performed two different kinds of "hard reboots" on the two printers: both holding the lower-right corner of the screen while the printer reboots, and also holding the lower-left corner

- I went into the printers' Service menu and Restored Factory Default settings.

- In the printers' network configuration menus, I tried several different configuration options, including deactivating IPV6 and changing the Link Speed to every available option.

Even after all of this, when the printers are plugged into our office network, the 79 Service Error message reliably appears within a minute or two, and the printers reboot themselves.

I reached out to HP Customer Support -- the printers are several years old and no longer under warranty, so I had to pay HP forty dollars to talk to me on the phone. After more than an hour of following their instructions, there was no improvement whatsoever. I believe a refund is pending.

As I said, this problem befell both printers at almost the same time, so it seems unlikely to me that it is a hardware issue causing the same problem on two separate printers of the same model. The most logical explanation I can think of is that someone in my office sent a bad/corrupted print job to one printer, and when that printer went down, they tried the other printer, infecting both. But the printers are now uninstalled from all computers after I cleared those computers' print queues and rebooted them, so I have no idea what is happening now.

I'll also mention that our new offices have a firewall and not a traditionally resettable router.

The best idea I have left is dropping these printers off of something very tall. Does anyone out there have a more practical suggestion? I would really appreciate the help.

[Repairatrooper]

I have seen some cases where the brand of network switch will cause this error and the only fix is a different switch.  Service documentation states this is typically a firmware error so performing a full reset and reinstalling current firmware might resolve the problem. The problem often with firmware is something is corrupted and simply updating the firmware does not eliminate the original cause so a straight upgrade of firmware does not resolve the issue.