Lexmark Optra M412 Fuser error

[msy]

Hi all

I have Lexmark M412 (4045). When i switch on the printer i get a "921 Service, Fuser error". I removed the fuser unit as soon as i switched off the printer. I think the fuser must be hot, because I took the fuser out as soon as i switched off the printer.


Therefore, I think the fuser is not getting hot.

There are 3 components I could think of been faulty. Lamp, Thermal fuse and Thermistor.

I checked the lamp and the filaments looks ok (no broken ones). I think the thermistor is working fine, because it gives me the error message. I’m not sure about the Thermal fuse.

Am I correct with my assumptions? Is there another way to check these parts? Is the lamp making the Hot Roller hot?.

Any suggestions for this problem?

I would be grateful to if anyone can reply me ASAP.

Thanks,

 

[CobolKid]

There is a temperature controller for the fuser built onto the (or one of the) circuit card in the printer as well. Its not uncommon to pop the controller’s solid-state relay, this is the thing that actually turns the lamp on and off. The thermal fuse is simply a fire safety device in case the temperature control system fails in the “on” mode. Check the fuse for continuity with a digital volt (ohm) meter (dvdm) set to the "ohms" (or the upside down "U&quot selection. It should be closed i.e.; nominally .2 ohms or less. You can check the lamp this way too, however depending on its type (ac or dc) and its operating voltage it will show some resistance value. The trick here is it must not show open, which is what your meter will show without its leads touching each other, typically an "OL" on many dvdm's. Do not forget to clean the lamp with isopropyl alcohol to remove your natural body oils before reinstalling it or it won't last very long if you do fix the problem. In addition, there is a thermistor or a thermocouple that rubs the roller the lamp is inside of, this is the temperature sensor for the controller. Make sure it's clean and not damaged.

 

[CobolKid]

A key here is how fast the error cmes up after powering on. If a minute or two pass, then most likely it is not heating and finally times out. This indicates a popped ssrelay etc. If it errors right after powering up, it could be a fused thermistor (thermistors tend fail by shorting) something like a fuser paper path sensor that is blocked or has failed.
You may want to contact Lexmark tech support, the error code will mean something more than the "call for service," message displayed.

 

[msy]

Hi CobolKid,

thanks for the help. I have contacted Lexmark and they were not that helpful with matter.

I'm not good at electronic stuff. :-(. I have few questions.
1) Is there away that i could check the controller’s solid-state relay ?.
2) I didn't get this "The trick here is it must not show open, which is what your meter will show without its leads touching each other, typically an "OL" on many dvdm's."

* The lamp states 220v and 600W.
* The error message comes out after 20-30 sec after i have switched on the printer.

thanks.

 

[bhockenb]

There is a small plastic guide on the end of the fuser bulb that can be installed 180 degrees from the proper position, preventing the bulb contact from making contact.If the fuser has ever been disassembled, this could very possibly be the problem.