NordicTrack C700 Treadmill Dead Console

[nrbrandt]

Hey all, I have the aforementioned treadmill which worked for a few months and then quit and I could use some help diagnosing it. The safety magnet key is in place and I assume working but there is no response from any of the buttons on the console.

When I opened things up I initially thought the LED on the main control board was blinking rapidly which appears to be the norm for NordicTrack but now I think it may really be blinking the SOS code. See what you think: https://imgur.com/hlhgaSG (see also: https://www.youtube.com/watch?v=QszHrCs72AM)


If you unplug the connector that goes to the console board (the 8-pin rainbow colored one) the LED comes on steady. With the connector unplugged there is 12v on pin 2 (the red wire) and nothing on the other pins. With the connector plugged in there is only about 0.3 volts on that pin and nothing on the others. I have no clue what any of the wires do.

I guess I'm looking for any advice on how to test and make sure it is this board that is bad and for how to figure out what failed on it if it is just this board. I know somewhere in the user manual it says not to leave the machine plugged in which we were never good at. So maybe there is something that commonly burns out on these? Seems like poor engineering for something sold as a commercial model.

Let me know if you need other views of the board. I haven't taken it loose yet to get a shot of the bottom but I can if you guys are pretty certain the problem is on this board.

[R_J]

Re: NordicTrack C700 Treadmill Dead Console

I would guess that the red wire supplies 12 volts to the console and either the console is killing the voltage, the cable has a fault (short) or the power supply can't supply enough current for the 12 volts
Open the console and unplug the cable, with the cable disconnected at the console but connected at the power supply, check the 12 volts. if it drops to near 0 the cable is shorted somewhere

[nrbrandt]

Re: NordicTrack C700 Treadmill Dead Console

Got any suggestions how to disconnect it? The bastards soldered/glued the wires right to the other board. . .

Also, pins 1 and 8 have continuity to ground. They're labeled 'G' so I suppose that's as it should be.

[R_J]

Re: NordicTrack C700 Treadmill Dead Console

Looks like the wires are soldered directly to the board, what resistance do you get when you measure between the red 12volt wire and ground?
If you do have a short on the red wire,you would need to unsolder it from the board, or if possible inspect the entire length of the cable, Does the cable get strained anywhere?

[nrbrandt]

Re: NordicTrack C700 Treadmill Dead Console

There is continuity between the red wire and both of the ground wires. There is a connector between the motor board and the console board and with that unhooked there is still continuity above the plug as well as right at the console board.

So that would mean something shorted on the console board, right? The only other thing I haven't tried is unplugging everything from that board to see if that makes it go away, but I assume that'd be unlikely to help.

[R_J]

Re: NordicTrack C700 Treadmill Dead Console

well if you measure low resistance between the red wire and the ground wire, something is shorted, if you ruled out the wire itself, then it must be something on the board, post clear straight on pictures of both sides of the board so we can trace the circuit.

[nrbrandt]

Re: NordicTrack C700 Treadmill Dead Console

Bottom of board

[nrbrandt]

Re: NordicTrack C700 Treadmill Dead Console

Top. The red wire connects to the 8 pin block in the upper left. It'd be the 2nd pin from the right with the board oriented this way.

[raider988]

Re: NordicTrack C700 Treadmill Dead Console

Just to be sure, you should test that the power supply is doing its job, disconnect it from everything it's supposed to power up and test the 12v line with a load, I'm still on cheap side and use led strips because i can easily change the current required by disconnecting parts of it.

You should remove the gue from the main board and desolder the 12v, check continuity on the cable. Continuity is your friend, if you can't find a datasheet for the board (which seems multilayered), than start sticking the probles around following the 12v rail and checking components. I'm no expert but the C14 on the top right of the bottom side doesn't look right.

[nrbrandt]

Re: NordicTrack C700 Treadmill Dead Console

I don't have LED strips handy, what other common items could I use to put a load on the power supply?

I have de-soldered the red power supply wire and there is still a short between ground and where it connects to the board. I also de-soldered the transistor which connects to that circuit because I thought those were one of the components that commonly fails and it tests the same as a new one. The short still exists with it removed so that should rule out the transistor and anything it powers, right?

What do I need to do to test C14? Do I need to de-solder it from the board? We're getting into stuff that's probably smaller than my soldering skillset. I can't tell for sure but it looks like C15 and maybe a pin of RG1 is also connected.

If anyone can find a schematic that'd be great. When I search for Rickenbacker59 the only hits I get are for guitar amps.

[R_J]

Re: NordicTrack C700 Treadmill Dead Console

It might be hard to track down the short but what you can do is (if you don't have a bench power supply) use a 9 volt battery, connect the [-] to ground and touch the [+] to the 12 volt input. dont leave it connected too long only a couple seconds at a time. the shorted component should get quite hot and you can feel around and find it.
Or some people will spray Isopropyl alcohol on the board and the hot component will cause the alcohol to evaporate really fast.

[budm]

Re: NordicTrack C700 Treadmill Dead Console

I don't have LED strips handy, what other common items could I use to put a load on the power supply?

I have de-soldered the red power supply wire and there is still a short between ground and where it connects to the board. I also de-soldered the transistor which connects to that circuit because I thought those were one of the components that commonly fails and it tests the same as a new one. The short still exists with it removed so that should rule out the transistor and anything it powers, right?

What do I need to do to test C14? Do I need to de-solder it from the board? We're getting into stuff that's probably smaller than my soldering skillset. I can't tell for sure but it looks like C15 and maybe a pin of RG1 is also connected.

If anyone can find a schematic that'd be great. When I search for Rickenbacker59 the only hits I get are for guitar amps.

It looks like c14 and C15 have been replaced before, I would remove them one at a time to see if the shorts go away or not.

[nrbrandt]

Re: NordicTrack C700 Treadmill Dead Console

Ok, removed c14 and the short went away. How do I figure out the right capacitor to replace it?

[R_J]

Re: NordicTrack C700 Treadmill Dead Console

Thats the input to the ic, a 4.7~10µf, 25~50v cap will be fine. find a regular electolytic around 10µf solder it in place and see if the circuit works. You can likely try the tredmill without the cap just to test if it works

[nrbrandt]

Re: NordicTrack C700 Treadmill Dead Console

Thanks for the help guys, I think we got it! I haven't put it back on the treadmill yet to make certain but I've hooked it to a power brick and it turns on now and makes noise when you press buttons so that's a good sign. I need a lot more practice as soldering but I think this will hold for awhile.

Makes me think a lot less of NordicTrack however if they're putting refurbished boards in new treadmills.

[budm]

Re: NordicTrack C700 Treadmill Dead Console

Those MLCC cap will fail shorts circuit, it also does not handle vibration and improper mechanical handling well either.