Low voltage power supply
What is the error message you are getting with the new fuser. Is this the same error you were getting before changing the fuser? If you changed the fuser because the old one was just at EOL ( end of life) but did not give you an error, have you tried to reinstall the old fuser.
It is possible that the new fuser was damaged in shipping, or not properly seated.
If both the new and old fuser give the same error message, then yes, I would agree that the LVPS would be the next part to replace, however, if they have different errors, then you probably have 2 bad fusers ( or one that is EOL, and one that was received damaged).
Before changing the LVPS, make sure you follow the steps below prior to the LVPS steps.
as far as where to purchase it if you do in fact need one, you can always do a google and ebay search for "Dell 5100cn LVPS".
I can provide you with replacement instructions if it comes to that.
See below for the actual troubleshooting needed for the fuser.
The following steps are the troubleshooting steps that should be followed for error code 010 397.
First, the definition of the failure is <IOT Fuser Failure>, and means a Fuser Error is detected.
1) With power off, reseat the fuser by physically removing it from the printer, then reinstalling it and locking it in place. Turn the power back on. ( if the error is still present, proceed to step 2 ).
2) If reseating the fuser did not resolve the problem, Replace the fuser with a known good fuser.
( if problem is not resolved, proceed to step 3)
3) Replace the LVPS ( low voltage power supply ). ( if problem not resolved, proceed to step 4 ).
4) Replace the PWBA MCU ( printed wiring board assembly - machine control unit ).
END of troubleshooting.........