Hi Folks, I have extensive time on this animal. This is the Johnson OPP motor control board. I drew schematics of this critter, and run a facility that repairs all makes and styles of motor controllers. Lets check a few things. With the controller in the treadmill, power up the treadmill and tell me if there are any console lights, beeping, buzzing at all. If not, it appears to be a power supply failure which is in the area of that green capacitor which is a 47uf, 200wv cap. To check the on-board power supply, you will need some thin meter probes and a DVM set to 20 or 50v range. Be extremely careful around powered electronics! Now, with the control board installed power up the treadmill and check for console lights or LCD screen. If none, place your Negative meter probe at pin/wire 3 from the center of the board, on connector JP3. This is a 9-pin connector. Counting from the left, negative probe on pin 3, then carefully touch the curved lead of the 3A rectifier diode D7 whic stands up on the pcb, right behind the electrolytic capacitor which is nearest that same connector, JP3. You should measure about +17vdc ;o) If not, you have found your trouble. There is a conformal coating on the board, so be sure you are making a good contact at D7.
Please feel free to contact me if you need further help. I was an electronics engineer for Johnson for years!!
greg
jatinahATrocketmailDOTcom