# Horizon Treadmill T81. Main motor will not run

#### hella

Joined Jul 23, 2017
7
Hi There, There is only one main switching FET on that unit, which is mounted to the heatsink/frame of the controller with a metal bracket, near the white current resistor standing up on the board, maybe marked 1.75hp on the side, which related to the factory stamp for the current sense resistor value to install. It may have been mentioned earlier, that if the main FET is blown or shorted, that kickback diode next to it will also be damaged. Both parts are a bit sketchy in this design and should be updated to a 35A FET and 30A 600v(prv) Ultra-Fast kickback, which also must stay isolated from that case or things will rip apart at power up. That motor rail resides on a "Hot Ground" and shorting the kickback to that case will release trouble in a huge way. Finally, if these 2 parts are ripped/shorted/blown, there will most likely be more issues long the drive-chain, thru the predriver circuits usually, and this is an all discrete design, one I cannot advise others to play with. I have spent at least a decade repairing these style of controllers, and I can tell you with certainty, if a single thing is missed during bench troubleshooting, a servicer can expect a large rip and smoke from the controller at full-load testing. I am used to it, most other would not be, nor would they maybe be prepared to power-down a hot-bench in a fast way to clear away that blast zone ;o) These boards, upper and lower of the controller, must be pulled apart to service, which is a tender job as well, as one missing or intermittent header pin, 40-connection points, or connection between boards will again cause major troubles. This is one of the "can't suggest folks try this at home" units. That motor rail bulk voltage sits at +165vdc for US models, and that bites terribly hard.
Do you have part number for the 35A FET and 30A 600v(prv) Ultra-Fast kickback?

#### R!f@@

Joined Apr 2, 2009
9,840
Mind you that if the motor turns a bit and shows E1 error, then there is no shorted components.

FYI, E1 error means there is no RAW DC available at the motor.
Which could only mean the power relay is not switching on to supply AC to the bridge.
by the way, this is not a relay problem, but bypassing the power relay will run the tread.
Bypassing is used to test it.

I do not recommend it. Do it at your own risk

I did fix one that shows E1 error last night, but the MCB is not same as @hella one. So I cannot say for sure where the problem lies.
But the issue was, motor turns a bit and E1 error. Tested the motor, tacho sensor and all power components, and found no issue. I found that the power relay was not turning on when the tread starts. Poking with the DMM testing voltages triggered the relay and starts to work. This led me to the actual problem.

@hella MCB is very different and I cannot ask you to poke around it.

#### tracy4419

Joined Sep 30, 2017
5
Good Morning,

I need help with my treadmill. Do you still help with this? I have a horizon LS780T. It was sitting in storage for a few years. Prior to this, it was like new. When trying to start it, the control board lights up, it moves up and down. When pressing start, something clicks in the bottom, I believe near the circuit board near the motor and it doesn’t start the belt. My brother in law looked at it and said the motor is fine.

Should I replace that whole circuit board?

Thank you,

Tracy

#### IamJatinah

Joined Oct 22, 2014
136
Good Morning,

I need help with my treadmill. Do you still help with this? I have a horizon LS780T. It was sitting in storage for a few years. Prior to this, it was like new. When trying to start it, the control board lights up, it moves up and down. When pressing start, something clicks in the bottom, I believe near the circuit board near the motor and it doesn’t start the belt. My brother in law looked at it and said the motor is fine.

Should I replace that whole circuit board?

Thank you,

Tracy
Hi There, Yes when I see notes about these I will often try to help. Not too sure about the above posts about "poking around and triggering a relay", it doesn't work like that in real life unless there is a physical/electrical issue, just as "baking a pcb in a home oven fixed something" which again wont reach temperatures high enough to melt or reflow solders of most types.

If you hear a relay, actually 2 of them timed very closely together which can sound like one click, the upper has sent the "Enable" control signal to the control board. If the belt doesn't move for 1-3 seconds there could be a couple reasons. The motor was "checked" so I assume with a Multi-Meter for a resistance reading on the motor black and red wires, when unplugged from the control board. Then these same black and red wires checked to frame ground, which should never read any resistance and should be open. If so, does the upper console error? Or, does the upper console act like the lower belt is running even tho it isnt?
Has the treadmill been moved I assume? All cable connections in place and no wires pulled loose? Horizon gives NO extra length, so when treads are moved, connections are routinely cut, scraped, broken. If you find the cables are all fine, then yes, that control board needs to be fixed or replaced. Part No.032669 and 032671 are identical, including PIC software. You can reach me at jatinahATrocketmailDOTcom directly if you need further help. Good Luck,

#### R!f@@

Joined Apr 2, 2009
9,840
In real life poking around works. If you a service tech @IamJatinah you would know this.
We techs say poking around means that during checking the board with the DMM with power and sometimes just a probe touch on a certain component can trigger a none working relay driver.
This is exactly what happened that led me to the issue. So it works in real life.

@IamJatinah Are you here to find customers to your repair business ?

#### IamJatinah

Joined Oct 22, 2014
136
You might try making a living "poking around". Poking would move, jar, add or remove impedences, change circuit parameters, change mechanical stress points currently on an assembly, and no, I most certainly do not pester folks here for any loot or business.
I have plenty going on and find that some folks get help on here. Ask any local electronics instructor about your "poking around" techniques, and no mention of a meter, makes one wonder a bit further. @R!f@@ what would a poking-around education run in college nowadays?

#### R!f@@

Joined Apr 2, 2009
9,840
Obviously you did not read my post thoroughly.
And it seems you have no idea who I am, as you are new here.
So just let it go and go on helping people as best as you can. I have no problem with that.

PS. I believe the way I said "Poking" mislead the meaning. So to clear the confusion I was measuring Voltages. Trying to find why the relay was not triggering and one component terminal triggered the relay. From that it was easy to find the fault. So in short I poked with the DMM probe. This finding helped to fix two E1 faults on two more separate treads. So far what I found out is that E1 error comes when the power relay fails to operate. I believe what you took from me saying poking was applying stress to components and PCB. If so, No I do not do that. Sorry abt that. My native language is not English. so at times I tend to write the wrong word beside my best effort.

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#### tracy4419

Joined Sep 30, 2017
5
I took some pictures. I tried attaching a video but it was too big to attach. It lights up fine on the top part where I hit start. The circuit board in the picture is where it makes a little click sound when I hit start. Theres a red light, but I'm not sure if that is normal or not.

#### IamJatinah

Joined Oct 22, 2014
136
Hi There, The red LED is normal after you hear the "clicks". Does the console keep clocking/timing like it thinks the unit is running? I have seen this fail like this but it can boil down to a couple of things. Most likely a failure in the drive circuits for the motor drive. These units should run about $200 from resellers, and a bit hard to fix for the hobbiest. Good Luck.... you can contact me at jatinahATrocketmailDOTcom if needed, and I buy these cores if you decide to throw any of them away. Most can be repaired and reused. #### tracy4419 Joined Sep 30, 2017 5 Hi There, The red LED is normal after you hear the "clicks". Does the console keep clocking/timing like it thinks the unit is running? I have seen this fail like this but it can boil down to a couple of things. Most likely a failure in the drive circuits for the motor drive. These units should run about$200 from resellers, and a bit hard to fix for the hobbiest. Good Luck.... you can contact me at jatinahATrocketmailDOTcom if needed, and I buy these cores if you decide to throw any of them away. Most can be repaired and reused.
The belt lifts up and timer starts like it's ready for the workout, but then the belt just doesn't move. The minutes keep going like I'm doing the work out.

#### tracy4419

Joined Sep 30, 2017
5
My brother in law looked at it for me and the motor works fine. I posted a previous message on this board, but didn't realize when I posted the pictures that I posted a new message completely separate from my original. My treadmill was practically new. I had it in storage for a few years and when I took it out, now I have this problem with the belt not moving and that clicking noise when hitting the start button. Everything else looks fine, just not sure where the clicking noise is coming from or why it is happening. My brother in law said it could be in the main console part or that circuit board that I posted the pictures of. I hear the click on that circuit board I posted, but my brother in law said it's possible that its coming from the console part not sending signal back to the circuit board in the pictures. Or that it's the circuit board in the pictures, but he doesn't have the tools to check all of the components on it to see which is not working. I thought about just purchasing a new circuit board, but I really don't want to spend the money if this is not the issue and it's something else. Would love to fix it, because I really love this treadmill and like I mentioned, it was practically new before storing.

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#### IamJatinah

Joined Oct 22, 2014
136
Hi All.... The "relays" you hear are supposed to click like this. In this tread system there are 4 relays total, all live on the lower control board, and there are no relays on the upper console board.
1 - Main "Safety Relay" (was required by industry) energizes/clears motor rail power
2 - PreCharge/Inrush control precharge relay allows cap inrush control
3 - Lift Up
4 - Lift Down
*** Never strap out the main relay during troubleshooting ***

From the sounds of things, unit was working before storage, not working after storage, makes me think of a couple of things I have seen thru the years when units are stored.....
Mice comes to mind first, as they love to nibble on wire-coatings, use the inner nylon fibers that run inside most cables to add strength, for beddings, and excrements can rot traces, cause shorts/opens, and kill high voltage circuits fairly fast. I've seen many cases of this very thing.
Then, please note, ALL manufacturers went to "tight" cables with little to no service loop lengths, meaning when you move a treadmill, you can very easily pull cable connections, pins from connectors held in with hot glue from China, and stress parts just by moving them. They do not move well. Also, inside the upright on one side or another, the console cable runs thru. This cable may have another hidden connection inside this mast.
Clicking tells us the cable makes contact for Power-Gnd-Enable to the lower board, so we can assume the cable is viable.
Lastly, moisture over time also erodes metals, traces, paths, leads and can cause problems.

This particular failure sounds like a moisture caused issue, I do know the drive-path most likely affected, but it is all surface mount devices and nothing a hobbiest can do. Reworking surface mount parts requires some training and patience. One would also need some experience with manufacturing to understand how these boards are made to know how to rework them well.
You can find my email info in the chain, and I can swap you a good unit for your bad unit if you'd like to keep the tread working and out of the landfill, but this failure will require some rework and a specific test set to repair in most cases. Good Luck ;o)