I have a overspeed condition and the service tech has 3 hours into it with no results. Do you have any troubleshooting steps. Model is 04390-3

If it worked before the main board was replaced it is pretty darn likely the problem is one the repair created, go old fashioned common sense tells me this. Call the repair company and discuss it with them, if they refuse contact the manufacturer customer service and apply some pressure

Google search showed this free manual page.

https://www.manualslib.com/manual/925783/Lexmark-X945e-Mfp-7510-Series.html?page=146

925.00
Service PC
cartridge

Description/Action
Outputs of the sensor (Y ATC) are not in the
specified range.
This error must be reset inside diagnostic mode
before troubleshooting or machine operation can
occur.

Go to
"925.00 Sensor (Y ATC) error" on
page
2-181.

-----------------------------------------------
Google search result:


https://printcopy.info/?l=en&mod=erc&brand=Lexmark&model=C935&code=925.00

Code

925.00

Description

Service PC cartridge Sensor (Y ATC)

Remedy

1 Reset the Y ATC failure lock out condition. 1. Enter diagnostic mode 2. Select Dev unit reset. 2. Select Y channel Perform a very large print test. Does the error continue? Go to step 2. Problem solved. 2 Check the sensor (Y ATC) for proper connection. Is the above component properly connected? Replace the Y developer unit assembly. Go to "Developer unit assembly removal". Replace the connection. 3 Perform a very large print test. Does the error continue? Replace the upper printer engine card assembly. Go to "Upper printer engine card assembly removal". Problem solved.

this means transmission range sensor circuit is not communicating correct data to the engine control module (ECM)
P0706 OBD II Trouble Code Transmission Range Sensor Circuit Range... , this link will explain your option's

Dear Sir:
You have 4 conditions when burning smell:
1) Very high belt/deckfriction.(Lack of lubrication by maintenance2) Short in the motor.(The same problem maintenance)3) Short in the wiringor electronics.You must have some skill in electricity or electronic or you can cal some service tech.4)Literally cooking the lacquer or cardboard core (on cheap machines) in themotor from belt friction or a drive system,The same lack of maintenance and lubrication.

And recommend that RUN the Calibration Software for easy diagnose and troubleshooting that coming with your treadmill, most of them the instruction step coming from the Hood of motor, and follow the instruction, or use your manual Ins.

sincerely. God bless you.

ernesto cuadra
managua, nicaragua. c.a.