Proform treadmill keeps blowing cord fuse

Thread Starter

Maaty

Joined Jan 23, 2020
13
Hi,
I recently faced a sudden problem witb my proform treadmill as it stopped suddenly during my exercise, after checking i found the fuse in the main cord is dead when i inserted a new one and prezs start, it moves for a second then stopped the treadmill Turned off as the new fuse blows again, i opened it and removed the the motor connection from the board and pressed a start no problem, and connected the motor to external battery rotated normally,
I will be grateful for any help!!
 

MaxHeadRoom

Joined Jul 18, 2013
20,073
That is one of the many MC2100 T.M. boards out there, I would first suspect the Mosfet mounted to the heat sink, most are IRFP250.
Max.
 

Thread Starter

Maaty

Joined Jan 23, 2020
13
Thanks again, but sorry for my silly question, could you illustrate it more for me or just share a thread to explain how to locate and replace
 

MaxHeadRoom

Joined Jul 18, 2013
20,073
It is the semi-conductor on the extreme left of those attached to the aluminum heatsink, IRFP50.
On second thoughts, when you tried the motor with a external battery, was it still on the machine with belt connected?
If not, check for excess friction etc on the belt drive.
Max.
 

MaxHeadRoom

Joined Jul 18, 2013
20,073
Another test of the board is to use an incandescent lamp in place of the motor.
Also the LED should be flashing steady when a command is given.
Max.
 

twohats

Joined Oct 28, 2015
97
While you are working on the printed circuit board (PCB), check the electrolytic capacitor (The small one) next to D9. It looks a little stressed, might be just the angle of the camera.
Please keep us posted with your repairs.
Good luck...……..
 

Thread Starter

Maaty

Joined Jan 23, 2020
13
Sorry being late, regarding motor test i also made it without belt attached but also fuse blows (i blowed mor than 10 now), i will attach a close photo for the mosphet it says g4pc40k, 324p, i searched for online purchase but i found only the first (g4pc40k) i cannot find 324p!!
 

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MaxHeadRoom

Joined Jul 18, 2013
20,073
Really the best way is to remove the board from the aluminum chassis and test the Mosfet, the large diode next to it, and the small SCR.
All could be suspects.
Max.
 

Thread Starter

Maaty

Joined Jan 23, 2020
13
Hi, this my recent updates, i failed to found the same mosfet in my area so some technician suggested to use another mosfet (the photo attached)
After installing it started to move then declined the speed, with no response when speeding up!!!
 

Attachments

MaxHeadRoom

Joined Jul 18, 2013
20,073
That G4pc40k, and G4pc50w appears to be compatible replacement.
But the original is a IGBT and you have replaced it with IRF540,? Mosfet that is normally found on these models.?
Max.
 

Thread Starter

Maaty

Joined Jan 23, 2020
13
That G4pc40k, and G4pc50w appears to be compatible replacement.
But the original is a IGBT and you have replaced it with IRF540,? Mosfet that is normally found on these models.?
Max.
Always appreciate your help Max,
But i managed to install the mentioned IGBT, tested the treadmill it started to move fast then declined, but after 5 seconds it moved constantly i left it to move for 10 minutes no problem but after riding it it declined then stopped again with blown fuse, again truly i have no idea what to do!!!
 

Thread Starter

Maaty

Joined Jan 23, 2020
13
Always appreciate your help Max,
But i managed to install the mentioned IGBT, tested the treadmill it started to move fast then declined, but after 5 seconds it moved constantly i left it to move for 10 minutes no problem but after riding it it declined then stopped again with blown fuse, again truly i have no idea what to do!!!
Update, I tested the new igbt it became shorted now
 

Thread Starter

Maaty

Joined Jan 23, 2020
13
Test the motor on a 12v automotive source for e.g.
Also remove the motor belt and see if the motor runs OK.
Max.
I already tested it it moves normally on both external batteries and without belt attached, and it was moving normally on the new IGBT
 
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