Treadmill - internal magnet intended for safety stopped working

Thread Starter

bananaman65

Joined May 25, 2021
5
Forgive me, I am new and have little to no experience with circuitry. I am very sorry if this is not the right place to ask or this forum is intended for more experienced people.

Hi, I have a Pro Fitness JX 260 / JX 263. I read up online that the circuit breaks and doesn't allow the treadmill to work without the magnet safety key, making a continous beeping sound which seems to be what is happening. I ordered a replacement magnet key, and also tried the original, but there is nothing on the inside to 'attach' the magnet to anymore, it did attach just a few days prior but not anymore. It has lost all its magnetism. I opened it up and looked inside, moved the magnet around the inside where the safety key should attach to, there is nothing there to attach to. It's almost as if the magnet disappeared or lost all its magnetism. Removed the cables and reattached, didn't work either.

Below is the picture of the part the magnet should be attaching to. You can see my attempt to dig out the gel or whatever that is to try to move the wiring around and try to get it to work.
magnet attach.jpg
Below is the part where the magnet should be attached to
attach1.jpgBelow is where the other side of the magnet (safety key) should attach from
attach2.jpg
The pcb
pcb1.jpg

My first guess is the wire I'm holding in the last picture (attached to the pcb the part which the magnet safety key should attach to) has stoppped working and lost its magnetism or a loose part i cannot find has broken off it. I am trying to identify what this part is and if i can find a replacement/bypass for this.
 

AlbertHall

Joined Jun 4, 2014
11,309
In your first picture, that glass tube inside is a reed switch. It makes a contact when a magnet is near it.
You can test a magnet by putting it near some iron/steel. Reed switches do not need a very strong magnet to operate.
Do you have a multimeter?
If so you test the reed switch by connecting the meter on an ohms range across the switch(with the treadmill disconnected from power). You should see the reading change when you bring the magnet near the switch.
If that works then connect the meter across the wires from the switch where they connect to the PCB. You should see the same readings.
 

MrChips

Joined Oct 2, 2009
23,515
The magnet is in the external detached key, not part of the circuit.
The safety switch on the circuit is a magnetic reed switch.

As Max suggested, firstly, try putting a jumper across the two terminals where the switch is connected and see if the treadmill runs.

After that is confirmed, bring the magnet close to the switch and confirm that the switch closes. Note that the orientation of the switch might make a difference.
 

Thread Starter

bananaman65

Joined May 25, 2021
5
Ok, after reading the responses i tried to 'jump' it by removing the reed switch thing completely off the pcb, then runnning an old charger's wire on the 2 points pcb where it connects. If that's not how you 'jump' let me know, because it didn't work, i tried a metal screwdriver and some other stuff to connect it and it still didn't work. I will buy a multimeter and see what i find with that.

Tried again with the magnet, running it around the reed switch still had no pull and did nothing. I checked the manual for this treadmill and there doesnt seem to be troubleshooting instructions for this continous beep - it could be something else but I think it is something to do with the reed switch. It had magnetic pull before which you could feel by having a magnet near it, now it doesn't anymore.

Below where it's written "safety" is where i tried to jump it by connecting the two wires together
20210525_162554.jpg
 

MrChips

Joined Oct 2, 2009
23,515
By your own admission you have little or no experience about circuitry.
Follow the good advice you are receiving.
Don't go about doing things willy nilly. You will only make matters worse.

If the treadmill does not work with a properly installed jumper to replace the reed switch then the problem is not the reed switch. The problem is elsewhere.

btw, you will not feel any pull between the magnet and the reed switch.
Connecting a power source at the reed switch connector was a bad idea.

So now you are stuck. Without a DMM and proper guidance there is little hope of resolving the problem. Is there a knowledgeable friend who can help you with this?
 

Thread Starter

bananaman65

Joined May 25, 2021
5
By your own admission you have little or no experience about circuitry.
Follow the good advice you are receiving.
Don't go about doing things willy nilly. You will only make matters worse.

If the treadmill does not work with a properly installed jumper to replace the reed switch then the problem is not the reed switch. The problem is elsewhere.

btw, you will not feel any pull between the magnet and the reed switch.
Connecting a power source at the reed switch connector was a bad idea.

So now you are stuck. Without a DMM and proper guidance there is little hope of resolving the problem. Is there a knowledgeable friend who can help you with this?
It was just a piece of metal wiring cut out of the charger, not connected to anything. I ordered a DMM
 

Thread Starter

bananaman65

Joined May 25, 2021
5
Tested the multimeter was working by setting it to check ohms and connecting the tips to each other, they read 0. I tested for continuity on the reed switch "thing" by setting the multimeter on the continuity test setting. At first, a beep wasn't audible (reading at 1) till I placed a magnet near it (then reading close to 0 or 0.03). After fiddling around with it more (putting a screwdriver into the reed switch and moving it around), it now beeps audibly and continously regardless of the magnet being there or not. It appears that it's working. I also tried to 'jump' the terminal where this reed switch would connect to on the PCB as shown in the last picture, that still didn't work. Is this indicative of a deeper problem in the PCB?

I am googling for guides to test resistors on the PCB itself, since it seems to have a lot of resistors. Would it be worthwhile to try this out to diagnose the issue?
 

MrChips

Joined Oct 2, 2009
23,515
Tested the multimeter was working by setting it to check ohms and connecting the tips to each other, they read 0. I tested for continuity on the reed switch "thing" by setting the multimeter on the continuity test setting. At first, a beep wasn't audible (reading at 1) till I placed a magnet near it (then reading close to 0 or 0.03). After fiddling around with it more (putting a screwdriver into the reed switch and moving it around), it now beeps audibly and continously regardless of the magnet being there or not. It appears that it's working. I also tried to 'jump' the terminal where this reed switch would connect to on the PCB as shown in the last picture, that still didn't work. Is this indicative of a deeper problem in the PCB?

I am googling for guides to test resistors on the PCB itself, since it seems to have a lot of resistors. Would it be worthwhile to try this out to diagnose the issue?
That is strange. When you move the magnet away the DMM should stop beeping.
(This is not related to your problem but still needs to be investigated.)
 

AlbertHall

Joined Jun 4, 2014
11,309
That is strange. When you move the magnet away the DMM should stop beeping.
(This is not related to your problem but still needs to be investigated.)
There should be no beeping with the magnet and screwdriver removed (in case the screwdriver is magnetised).
 

Thread Starter

bananaman65

Joined May 25, 2021
5
That is strange. When you move the magnet away the DMM should stop beeping.
(This is not related to your problem but still needs to be investigated.)
I found that strange too. Initially, it was only beeping once the magnet was in range and only then. After I messed with the screwdriver in the reed switch, it started beeping always regardless of the magnet being near or not. Maybe there is something near that is magnetic, I will look into it. I might have damaged it.
 
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