Control panel lights up but do not work..

Could the child lock be activated .....

It appears that there may be an issue with the speed and incline controls on your used Sole F85 treadmill. Based on the information provided, here are a few troubleshooting steps you can try:
1. Check the control panel connections: Ensure that all the cables and connectors between the control panel and the motor control board are securely plugged in. Loose or faulty connections could cause issues with the speed and incline controls.
2. Inspect the control panel buttons: Examine the buttons on the control panel to see if any are stuck or not functioning properly. Sometimes, debris or dirt can accumulate beneath the buttons, preventing them from working correctly. Gently clean the buttons and the surrounding area to remove any obstructions.
3. Test the speed and incline motors: The issue could be related to the motors responsible for adjusting the speed and incline. Test the motors individually by manually applying power to them while disconnected from the control panel. Observe if they respond correctly to the input. If the motors do not respond as expected, they may need to be replaced.
4. Examine the motor control board: Inspect the motor control board for any signs of damage, such as burnt components or loose connections. If you notice any issues, it may be necessary to replace the motor control board.
5. Seek professional assistance: If the above steps do not resolve the issue, it is advisable to contact a professional technician with experience in treadmill repairs. They will have the expertise and specialized equipment to diagnose the problem accurately and recommend the appropriate course of action.
Since your treadmill is a used model and the control issue has persisted for some time, it is possible that the problem is more complex and requires professional attention. A technician will be able to provide you with a more precise diagnosis and help you determine the best solution to get your Sole F85 treadmill functioning properly again.
Remember to prioritize your safety when dealing with electrical equipment, and always disconnect the power source before attempting any repairs or inspections.

These videos might help

I'm guessing that a schematic would be difficult to obtain because the Nordic Track design is proprietary. The incline up/down calibration might be running at start-up which can take a couple minutes, after which, the machine returns to "normal" and buttons now respond. If this is not you case then a repair person may have to intervene.

Sounds like the button on the panel is stuck somehow, I think this because when you switch the wires this would reverse the polarity to the incline motor.

can you tell if the panel is recognizing the pushing of the incline buttons, like with a beep or light or something? If it didn't seem like it's responding this may be because one button is constantly stuck down.

This problem needs more details to service....seem like you have multiple problems...better to call for service 877-805-1030

you need to replace the key pad

I’m happy to assist further over the phone at https://www.6ya.com/expert/james_1cb31da1bc8c6102

these are instructions on how to calibrate your incline motor:
http://www.treadmilldoctor.com/Incline-Calibration-Instructions?utm_source=fixya&utm_medium=CPC&utm_campaign=Mendi

Merit 725T. The treadmill has gone into a "10 degree" incline mode on its own, and will not respond to the control panel

It is the control panel. You can actually just replace the circuit board on the control panel and it should fix this.

Try cleaning the control panel and all the buttons/keys. If problem persists, try banging the keys individually. The control panel will not respond if any of the keys are stuck down.