Author Topic: What is the magnet by the PSU for? Sebo X4 (Read 4929 times)

tonsberg · « **on:** April 30, 2020, 10:30:15 am »

While I am still in Sebo mode, can anyone tell me what the small magnet is for? The one next to the power supply board?
It doesn't seem to do anything as there is no sensor associated with it. I have read that various faults are cured if the magnet is put back in position after falling off.

I assume it is a ferrite magnet but have not checked. Maybe I have misinterpreted the posts that I have read? It niggles if I can't understand something like this!

Thanks in advance,

Andrew.

MVacs · « **Reply #1 on:** April 30, 2020, 02:17:34 pm »

The one by the power supply board actuates the servo motor that raises and lowers the machine.

tonsberg · « **Reply #2 on:** April 30, 2020, 02:52:56 pm »

Now I am confused! Surely the magnet that operates the Raise lower mechanism is on the opposite side of the machine. This magnet is the one that the Hall effect sensor uses.

The one I am referring to is not far from the mains relay (the one that shuts off power to the motor) on the power board. On my machine it appears to be a black circular disc stuck on to the plastic. I seem to remember a post referring to the magnet becoming loose and finishing up underneath the power board.

Maybe it isn't a magnet at all, although what it is is a mystery. Or it could be that what I call the power board, is not the same one that the previous post referred to (I mean the one one with the transformer that does 240v AC to maybe 12-14Vv Ac and then goes to the main control board,where it is rectified to around 17 v DC.

Seems I may be barking up the wrong tree, or am I?

Thanks for reading my meanders!

Andrew.

MVacs · « **Reply #3 on:** April 30, 2020, 03:48:15 pm »

I'm referring to this one:

What is the magnet by the PSU for? Sebo X4

If that magnet is missing, the machine wont raise and lower.

tonsberg · « **Reply #4 on:** April 30, 2020, 04:13:27 pm »

Hello,
Yes that is the magnet I am referring to. So how is that sensed? I was under the impression that the magnet on the "clutch" operated the raise and lower mechanism. I thought the Hall effect sensor detected the rotational speed of the "clutch". If the speed drops (Due to increased drag of a carpet) this raises the height motor. If the clutch speed increases (Vac on hard floor) then the height motor lowers the Vac. A type of negative feedback, to keep the main Vacuum motor at a constant speed.

Do I take it that I have completely misunderstood the working of the raise / lower system? if so how does the magnet by the power board interface with the raise / lower system? It just appears to sit there without any interface to the main PCB board. What am I missing?

Thanks for your patience,

Andrew.

MVacs · « **Reply #5 on:** April 30, 2020, 08:12:59 pm »

Our chap told me it activates a little thing on the board like an alarm door sensor which tells the servo to sense height, if that makes sense. The boost buttons on Pet models work by a similar method.

The two magnets on the yellow wheel where the belts run also do something else relating to sensing the belts and brushroll tension he said. But brushroll tension also relates to the height mechanism. I think when the machine is upright the magnet's position tells the machine to assume full height and if it's missing not lower at all. Having got the lower signal by that magnet moving, brushroll tension sensors then senses the exact height to set it at. Something like that.....

But the fact remains that when that magnet comes out, it doesn't go up and down. Glue it back in and it often will.

tonsberg · « **Reply #6 on:** April 30, 2020, 09:05:15 pm »

Thanks for the reply. I am not sure if either of us fully understand how that magnet affects the height. Next time I have the X4 in pieces I will take a good look at the various components on the power supply board and see if they have any connection to the magnet. None of the ICs on the main board are anything to do with remote sensing.
Looks like a good challenge!

Thanks again for your help and patience,

Andrew.

MVacs · « **Reply #7 on:** April 30, 2020, 10:35:05 pm »

Quote from: tonsberg on April 30, 2020, 09:05:15 pm

I am not sure if either of us fully understand how that magnet affects the height.

There is no workshop manual published. We learn as we go as with anything. But we understand how to fix them as we do it every day.

tonsberg · « **Reply #8 on:** May 01, 2020, 09:52:44 am »

Hello MVacs,
I didn't mean to imply that you didn't know what you are doing! You know infinitely more than anyone else on the forum.
What I was trying to say was probably neither of us knew exactly by what means the magnet interacted with the raise lower mechanism. I do not doubt for a minute that the lack of said magnet will stop the raise / lower function.
Please accept my apologies for what what may have been taken as a sleight .

Thanks once again,

Andrew.

Ilovemysebo22 · « **Reply #9 on:** May 03, 2020, 09:40:48 pm »

I think the reason for confusion was because it wasn’t made clear how exactly the magnet near the power board affects the height adjustment, the magnet corresponds with a sensor so that computer knows wither or not the machine is in the upright position so that the computer can raise the height in the upright position so that the tools can be used with out the brushroll contacting the floor. I assume the used a magnet for this as it will last longer that’s a mechanical micro switch (why I love sebo). As far as I know the magnets on the clutch is so the speed of the motor can be measured for the auto height adjustment. Hope this helps the confusion.

John Stuart · « **Reply #10 on:** September 24, 2020, 09:56:05 am »

Quote from: tonsberg on April 30, 2020, 10:30:15 am

While I am still in Sebo mode, can anyone tell me what the small magnet is for? The one next to the power supply board?
It doesn't seem to do anything as there is no sensor associated with it. I have read that various faults are cured if the magnet is put back in position after falling off.

I assume it is a ferrite magnet but have not checked. Maybe I have misinterpreted the posts that I have read? It niggles if I can't understand something like this!

Thanks in advance,

Andrew.

That magnet activates a reed switch that raises the brush/nozzle all the way up, when the handle is in the up and locked position. For example, when the extension hose is being used. Notice the position of the magnet when the handle is up and locked, it is in close proximity to the reed switch on the power supply board.

MVacs · « **Reply #11 on:** September 24, 2020, 06:11:34 pm »

Quote from: John Stuart on September 24, 2020, 09:56:05 am

That magnet activates a reed switch that raises the brush/nozzle all the way up, when the handle is in the up and locked position. For example, when the extension hose is being used. Notice the position of the magnet when the handle is up and locked, it is in close proximity to the reed switch on the power supply board.

What John said.

And welcome to the site, John.