hi all

i'm hoping one of the electronic gods on here can guide me to solve a problem with a tredmill

i'm not very knowledgeable as you's about electronics, but i know the basic stuff....an i'm a trier, an electronics has always fascinated me...

ok the problem...

the treadmill just stopped working, it had blown the internal fuse on the MCB...i replaced the fuse an it blow again.

i disconnect the motor (180dc) an tried it with a car battery an it turns ok....then i noticed with the motor unplugged the fuse did not blow, but as soon as you plug the motor back in the fuse blows? i'm not getting any voltage at the terminals wear the motor plugs in to the MCB, theres no obvious sign https://www.google.co.uk/search?hl=...YDQDA&ved=0CB4QvwUoAQ&q=obvious+signs&spell=1on the MCB of any broken components on the board itself....

couple of pics...

http://i.imgur.com/HBTjX.jpg
http://i.imgur.com/jRnlr.jpg
http://i.imgur.com/E529C.jpg

thanks guys

 

Try replacing the rectifer and mosfet the same time an see if it help.

 

I suspect *trini1* is on track, though can you add a picture of the underside of the PCB shown ? I'm amazed that those tiny diodes are the rectifier for a treadmill motor.........

 

I suspect *trini1* is on track, though can you add a picture of the underside of the PCB shown ? I'm amazed that those tiny diodes are the rectifier for a treadmill motor.........

Actually, I think those small diodes are for something else. The rectifier looks to be on the bottom side of the PCB next to the large capacitor and what looks like a NTC/PTC. It is probably about a 15 - 20A bridge rectifier.

 

thanks for the reply guys yes theres a bridge rectifier (KBPC1510) i've tested the small diodes an they are doing what they supposed to do.... i didn't test the bridge rectifier because i think i'll have to remove it...an you have to keep it cool when removing/fitting one? also they are three mosfets, should i replace them all? a few more pics http://i.imgur.com/5cKUQ.jpg http://i.imgur.com/JB448.jpg http://i.imgur.com/2ymcT.jpg http://i.imgur.com/HYe18.jpg

 

That picture is more like it, and that monolithic bridge is more than likely the culprit. Have you any room for a substantial heatsink in the chassis box ?? 'cuz those puppies can put up some heat.........forced ventilation wouldn't hurt either.....

 

the bridge rectifier sits directly on the chassis box, i could put a small fan in there?

 

thanks guys!! the culprit was the mosfet, unfortunately they had stopped making the one i was after, so had to get a similar one.......but its up an running now i'm glad i found this forum, lots of interesting stuff to read an learn thankyou again guys