Wireless Canon MP640 Printer Stopped Working (and the fix)

It is surprising how often the Canon MP640 printer fails to print.  The only indication of the problem is that the printer queue on the PC reports an “error”, and obviously, no print.  Nobody  messed with the printer and the printer just sitting there shows  no indication of a problem (flashing lights,  grinding noises, paper spewing out etc).

The printer allows you to view the network configuration and by going through the menus, and it is clear an IP address was assigned to the printer.  Ping the IP from the PC and  the port is pingable.  That means there is IP connectivity (see notes on the ping test below).  Something is messing up the communication between the PC and the printer.  The thing between them is the router so that is the next stop.

The fix if ping succeeds but still cannot print – try this and check for a router configuration problem.

Next, logged into my wireless router which is a Linksys WRT54GX2 running WPA2 personal security with MAC filtering.   In the Wireless Security Tab,  both  WPA Personal and WPA2 Personal were checked.    I unchecked WPA Personal.  Printer started working.   Why  were both checked?  Who knows.

Ping fails – router problem – reboot the router.

An error occurs in print queue suspiciously like the case above but the printer IP is not pingable meaning no IP connectivity.   Go through the menus on the printer.  If it cannot see the router’s SSID then the printer has no network.  In this case it’s probably the router. The fix- recycle power on the router to reboot.  To do this, pull the power plug on the router for a few seconds, then plug back in.  This fixes the problem – takes a couple of minutes for the router to reboot and the wireless devices and printer to reacquire the network through DHCP.

What’s up with this router huh?   It’s frequently involved in cases where the “internet is down” in the house.  If it’s not the cable company, it’s usually the router, the cable modem, or both.  Diagnostics frequently begin by nuking one or the other or both by pulling the power cables out and replugging.  Try to be methodical when doing stuff like this and it’s best if nothing important is up on your computers!

More on the Ping Test: 

Just in case this talk about ping is not helpful,  ping is a network troubleshooting tool.  The term ping dates back to the second world war submarine warfare sonar technology. The principle  is to send a loud sound called a “ping” from a loudspeaker under water.  An echo would indicate the presence of something out there.  In tcp/ip networking, a ping is a special packet sent to a specific target (identified by its IP address) which responds back with an echo response.  This tells you that the target, in this case, the printer, has a (most likely) functional network connection.  A network printer that does not respond to a ping has a network problem, and that would be a likely cause of printing failure.  To do a ping test, you need to 1) find the IP addresss of the target printer and 2) run a ping command.  In the case of the  Canon 640 wireless printer, one way to determine the IP address is from the printers front panel.  Use the dial selector to navigate:  device settings > lan settings > confirm lan settings > wireless lan settings > ip address.  In my case, I see  an IP address of 192.168.1.102.  Next on your windows PC, from the start menu,  get to a command prompt by typing “cmd” in the search field, then type  “ping 192.168.1.102”.     If you get lines of consecutive replies, that is the printer responding to your ping echo requests.  If you get no response, that is the indicator that the devices (your PC and the printer) are not talking to each other.   As always, google ping for more.