Treadmill Motor / Power Board Repair

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Treadmills come in 2 usual flavors, 3 phase brushless and then there's brushed DC.
This power board had a popped fuse which means there's a short -somewhere. Let's find it.
In the video I generically call 2 components "mosfets" - which I knew better.
In this design an Insulated Gate BiPolar Transistor (IGBT) is pulsing DC to the motor (to control speed) while the other component is a fly back diode (free wheeling diode) for emf. (see my other treadmill repair video for replacing defective fly back diode).
An alternate design uses an H Bridge and 4 mosfets to control speed and direction.
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[@BjornV78]

2:08 The thirth bridge rectifier on the top left corner.

[@BetterBiomedChannel]

I can't believe that I forgot the large bridge unit on the back

[@BjornV78]

@@BetterBiomedChannel , i think you have overseen it, because it was covered with thermal paste. Bridge rectifiers are normally not connected to a heatsink, and just flapping in the breeze.

[@Jean_villegas]

im from new york, ive fixed computers alot since like 1999. Ive seen lot of changes. I saw a craigslist ad of someone giving away a broken free treadmill and to fix was a pain

[@BetterBiomedChannel]

What was broke / defective?

[@Jean_villegas]

@@BetterBiomedChannel forgot its been awhile but wasnt easy

[@carlkellogg5342]

What make of board and # ? what did it come out of please ?

[@sphinxios]

so big and you did almost miss the 3rd bridge, personally i would have exchanged both IGBT's if not too expesive cause the heat could have changed its specs, it is an IGBT not a MOSFET

[@BetterBiomedChannel]

Out of sight, out of mind!

[@BetterBiomedChannel]

I made corrections in the video description. Thanks!

[@BetterBiomedChannel]

After watching this I realize I shouldn't do videos at 7am... I'm talking while I'm thinking and I realized upon review that several things are wrong. I was soo tired. The IGBT pulses dc to the motor and the other semiconductor is a freewheeling diode which allows bleedoff when the power to the motor is stopped while the motor is still in motion (now generating electricity). I am so sorry for the errors. I wanted to diagnose this board and get a quick video in before heading to the airport.