Avanti XFIT 2P exercise treadmill stops randomly - Page 1
Forum section: electronics / repair

author: Circlotron
author_rank: Super Contributor
timestamp: April 21, 2025, 05:58:23 am
content: Bought this thing new in Sept 2008 for AUD$3000 and has only had minor use. Sat for about 10 years doing nothing and finally relocated it and started using it again about 6 months ago.Power it up and set it going and the belt starts moving as it should. After a random amount of time, anywhere from 2 seconds to 20 minutes the belt will stop abruptly and pushing the stop then start buttons does nothing.If I push the belt manually the distance counter increments so the motor rotation sensor appears okay. (edit - there doesn't appear to be a motor rotation sensor on this one, so that's a bit odd.)Motor is definitely okay. I ran it on 20VDC from an external supply for 1-1/2 hours and it didn't miss a beat.Removed the motor PWM driver board and resoldered all solder joints and replaced the three electrolytic caps.Unplugged and replugged every connector I could find.Inside the user control panel there is the main board and a smaller one. Pulled out the smaller board and replaced three small and one large electrolytic caps.Things have not improved... Is there a service manual for these things? Is there some kind of diagnostics available by holding some keys down at power on? It seems like the main board is telling the motor PWM board to stop. Power it off for several minutes and it will start again like nothing has happened and run for a short time and stop again. When it has stopped the user control panel stays powered up.

author: MathWizard
author_rank: Super Contributor
timestamp: April 21, 2025, 07:15:20 pm
content: Do you have an oscilloscope ? It would be nice to monitor the the mircocontroller signals sent to to the motor driver circuits. There might be more than 1 micro too. See if the command to stop gets sent, or if it's still sending run commands. Then focus on the analog parts, like maybe the PSU to the motor driver circuits.I didn't find a schematic's, but if I was happy with the PSU section, and it's output voltages seemed reasonable, I'd then start at the motor, and work back and map the motor drive circuits, until I found where the MCU signal comes in from. But if I knew where it was, I'd start there.Depending on how hard it is to access the PCB when it's running, I'd identify some key places, and solder on a few wires, and maybe even drill a hole to run the wires outside a case, if I had to.I'm sure there's plenty of ways to get a shock from high power stuff like this, so be careful. I'm in no rush, so I'd probably have a good check over of the PSU too.I think a lot of treadmills have the main logic and MCU circuits up in the console, so really there's not that many wires going back down to the PSU and motor drivers. Some are for power and turning on/off power, some would be sensors and sensing circuits, and then ones for commands to the motor. Now the motor commands, IDK how they normally do it, but it could be as simple as a DC voltage, or some PWM signal, or some binary code to some other controller. So yeah an oscilloscope would really be useful for finding all this out.

author: Circlotron
author_rank: Super Contributor
timestamp: April 22, 2025, 07:23:56 am
content: Yeah, got a scope, but I'm just about to chuck this thing out I'm so sick of it.Pic of main board just for interest's sake.