Trotter 685 Treadmill

[atw58]

Greetings to all the EE community,

I have this gym quality treadmill which displays an "Err Code 08" (power train) when powered up and it doesn't respond to any normal commands. Going into diagnostic mode, individual input, logic, sensor tests pass except the DC amps where the motor does not run at all. When working the speed can be increased/decreased and the display shows the DC amps supplied to the motor. My thinking is the Power Control Module (PCM) detects an error condition related to supplying power to the motor then sends a signal to the display/logic board preventing power applied to the motor.

The treadmill is no longer supported by Cybex (Trotter owner) and they can't/won't provide any service or troubleshooting manuals.

Here are some basic troubleshooting observations.

240V AC is present at the output of the line filter.
The large capacitor charges to 270V DC.
LED 1 and LED 2 are both "On" on the PCM motor control board.
There is some discolouration at the 2 DC motor pins on the main AC/cap/motor green connector.
No signs of burnt parts on the PWM board.

Hoping someone who has experience with this unit see this plea and can provide some guidance. Even a schematic would be great to troubleshoot this further on my own. Posting here is a bit of a long shot but anything can happen on the internet.

[eKretz]

I've repaired a few of these (treadmills, not your exact brand/model) for others and all of the failures were blown rectifiers and a few diodes in circuit with them. Your numbers make me think yours could have a similar problem. A full wave bridge rectifier with filter cap should produce closer to 340V DC at the output of the filter cap with no load with a 240V AC input. Unless there's a transformer in between dropping the voltage coming in to the rectifier?