Fixing a broken treadmill – Estleys M600+ Portable & Foldable Treadmill

Slightly off topic but hoping this may well help someone in future.

I saw a treadmill being sold cheap locally. Had little use but had developed an error and refused to work. There was nobody else interested so I stepped in and paid £50 for a nearly new Estleys M600+ treadmill.

Link here for sale!

These retail at £450-£600 new so I figured it was a worth a punt and at worse I could probably sell the working bits and recoup the cost.

Other option would be to strip the mechanicals off and make an unpowered, manual unit, possibly for use at my desk.

When I picked it up I was impressed by the unit. It’s well made, certainly light compared to a gym quality one but crucially does fold flat enough to slide under a bed or sofa. It runs up to 8mph so is fast enough for most runners. It’s an ideal lockdown tool!

First Step –

Turn it on. All lights up but as per the advert has ‘Err’ on the screen and makes a warning beep. Not the most helpful error code. No pressing of buttons will get it to do anything or show a better code. Manual suggests the Err code is a safety key issue.

Next page also suggests a safety key issue. It’s a magnetic key so I tried swapping it in and out, and replacing with a stronger magnet from the fridge. No change. So it could be a ‘change computer screen/display monitor’. Let’s hope not as probably an expensive part.

I took the cover off the motor area. There isn’t too much to these units so a limited number of things that can be wrong. Visually it all looks good and a diode on the main board lights up so it’s getting power at least.

NOTE – I’m playing with the unit open and at times live. There is 240V power there. It could make you jump. Don’t be an idiot with this and minimise any danger. Mine was connected via an RCD device to trip in event of any issues.

Motor Test

Starting with the basics, is the motor goosed?

Note – the motor on all treadmills is a DC unit (direct current – like a battery) not an AC (alternating current – like the mains power) so you can’t just wire the motor directly into your 240V supply as you’ll fry it.

The benefit of being DC is you can more safely test and almost any battery will make it move a little to test.

The video below shows how to do it using a small 12V battery. Other videos show using a tiny 9V battery from a smoke alarm.

I tested mine with a 12V car battery charger – pulled the motor cables from the main board and connected directly to the charger, then turned on (making sure no risk of short circuits or bare wires touching anything).

It had enough power to ‘flick’ the motor but not turn the belt. If I gave the belt a helpful push it then had enough to keep it moving. So motor was good.

Note – the polarity of the battery you use will affect the direction the motor spins, so don’t be surprised if it runs backwards, just make sure you connect the cables back to the main board in the correct polarity, likely terminals are marked “+” for the red/brown cable and “-“ for the black/blue wire.

If your motor won’t turn at all then you can try disconnecting the drive belt from the treadmill belt to reduce resistance and try again. If it still won’t it may well be faulty and there’s various checks you can make with a multimeter to measure winding resistance.

Main Board –

Not a lot to test on this for the home DIYer. With the unit turned off and unplugged you can make some basic checks.

  • Are the power cables connected from the mains socket?
  • Are there any inline fuses that could have blown (most don’t have them and rely on the plug top fuse)?
  • Are the cables to the motor connected?
  • Is the multiway plug to the controls and the display connected?
  • Do any wires look frayed or broken?
  • Any obvious discolouration from an overheating component on the board?

These boards are pretty specific to each make and model of treadmill so unless you happen to have a working identical treadmill to hand to swap the board over this is little else you can do to test.

Mine all looked good and as said above, it had a reassuring light on so was getting power. Of course the light could have meant an error, I had no way of knowing.

Cabling to controls and display –

Given everything in the base looked good, I opened up the rear of the display and control. This is connected by a small 5-way cable with a multiplug. They’re not especially well made so inspect the end of the cable where it connects to the main board in the base and the other where it connects to the control board. Given this is a treadmill that is often packed up and folded the cabling and joints are at risk of becoming trapped or kinking and breaking. I disconnected both ends and did a basic continuity test the length of the cable ensuring pin 1 on one end was connected to pin 1 on the other. If they’re all OK then you can repeat to ensure pin 1 is not connected to pin 2,3,4 or 5 indicating a likely split in the lead somewhere and cross linking. Mine all tested fine and cable had no visual faults.

Control Board & Buttons –

Once tested everything else so fault is likely in the control board, display or buttons. This is where people are prone to spilling drinks or sweating over the unit so did a quick check for any discolouration, suspicious stains or similar that might indicate a short. All looks good.

It’s worth noting on the M600+ the flip up screen plugs into the control board and has the buzzer inside to make the beep so without it connected you won’t know if the warning beep is still present.

There isn’t much else to check on this unit. The screen was lighting up and making the beeps so likely working despite the warning in the manual. The buttons each made a further warning beep is you pressed them so evidently worked and since they’re connected to the screen via the control board you can assume that is working.

Safety Key –

The only item left to check is the safety key device again.

There are two types, one uses a magnet as part of the key and if you lose it can be replaced with any magnet to form the circuit and make the machine usable, or you can buy replacements off eBay for as little as £5.

Others have an insertion key, a small piece of metal on a plastic holder that is inserted and completes the circuit to make the machine operate. These tend to be on higher end machines and are a bit more difficult to replace. Your manufacturer should sell them so check directly.

The M600+ has a magnetic key and I’d tried several other magnets to get it to work as a first check with no luck. The unit has a small safety circuit board with a basic reed switch activated by the magnet, located at the front of the machine and wired to the main control board with a simple two cable lead. It forms a loop in normal operation, completing a circuit from the control board, out to the safety board and back. Any break in this loop either from a missing key or a damaged cable etc would break the circuit and stop the machine.

Safety switch board with 2-pin connector

Easiest way to test is to disconnect the cable from the safety switch board and link across the two terminals to complete the loop. This remove the key and the safety board as issues.

Success – the machine when powered up beeped, but just the once to indicate it was on, and was ready to go. It ran up nicely to the max speed of 8mph.

So the issue is either the safety key or the safety board. The cable to it has been linked out at the board end so that’s been proven to be OK.

If you were happy to body it, you could just leave the cable linked out so it always runs, but you’d have no safety switch for emergency.

Time to investigate further.

First check is to connect a continuity meter on the two terminals of the board. It’s as simple as a circuit can get. When a magnet comes close to the unit it closes and completes the circuit. Or it should.

No matter how close I got the magnet I could not get a circuit from the pin connectors around and back.

I tested with the meter probes on the pins of the reed switch itself (you can see them in the photo two above) and success! The reed switch opened and closed as expected. So the fault is either on the board itself or the joints to the connector.

Some inspection showed a minor surface wear in the PCB track that was deep enough to prevent a current flow. How this happened inside a machine I don’t know since it allegedly did work originally. I rubbed the area down and ran some solder over the gap to close it and reassembled. Sadly I didn’t get a photo but appeared like below:

For advice on how to repair then check HERE

Treadmill now works perfectly and runs up well, safety key works exactly as it should.

6 thoughts on “Fixing a broken treadmill – Estleys M600+ Portable & Foldable Treadmill

  1. Hi mark I picked up one of these it turned and counted down with the beeps but nothing happened it just came up with E7 I didn’t see that code on your pics could you help please


  2. Hi…I have lost the manual for it…Does the manual say what is E7 and E8? Would it be possible to post the screenshots of those?


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