Lidl hand cordless vacuum

[Dave Plowman (News)]

Have one of these a few years old which is ideal for the car and small jobs.

Battery is fine - but when you switch it on, the motor sort of oscillates rather than turning. Was an intermittent fault, but now permanent.

The PCB is far too involved to draw out a schematic, so I'm a bit lost. Not sure how much of it is a clever charger, and how much the motor control. No obvious dry joints.

It's one of those devices which gets far more use than the low cost suggests. And is handy to store due to the wall charger bracket - no room for a larger one like a Dyson, etc.

[Lee]

Motor bearings may be sticking, does it turn freely? What sort of access do you have to the motor and what type is it?

If it's a normal permanent magnet type, I'd be inclined to de solder one wire and see how it runs from an appropriate PSU first...

[Roger Mills]

Mine failed in a similar way. It made a ticking noise - a bit like a distant machine gun - rather than rotating.

Mine was under 3 years old, and I still had the receipt. When I described the symptoms, Lidl declared it to be 'terminal' and sent me a new one. They didn't want the old one back.

I then took the old one apart, and got it to run in short bursts by by-passing some of the components on its PCB - but that wasn't a real solution.

[Dave Plowman (News)]

That's it.

Sadly, didn't keep the receipt. Which I do for most Lidl stuff like power tools. And because of that it's failed. ;-) But it could well be more than

3 years old.

If I had a schematic I could make a better guess what had failed.

The motor itself is ok - it runs off an external PS just fine.

[Lee]

Ah, now that's a bit more descriptive. Presuming that it's using a SM (buck or boost since I don't know the voltages), got to be worth checking the caps...

[Dave Plowman (News)]

It is a pretty complex PCB. I was guessing at PWM drive or somesuch. It has two Li-Ion cells in series so probably enough volts for a motor. But no large caps which would be the first suspect.

[Lee]

Fair enough, still sounds like a stalled oscillator though, are they using a micro/pic to generate the PWM signal? Could be a failed resonator or clock cap on the micro maybe. Seems feasible it's something basic given it's the second unit with the same apparent fault.

[Lee]

Another basic thing that comes to mind is the possibility of a current sense resistor drifting - might make the micro think the current draw is too high...

[Bob Minchin]

Dont really see why they would use PWM? surely no need for variable speed in this application. Maybe try bypassing the electronics and see if it will run on the batteries alone?

[Brian Gaff]

You say not the battery, but some of these control circuits are clever in monitoring the battery volts at start, and if its over current, then it stops and starts and stops and starts thinking maybe the motor is jammed. If you can get at the spindle you can sometimes with good timing get it to run by turning it as you start it. I think as the batteries in portable gear gets less good at supplying the current the system just stops it or stops and starts it. I have a Remington shaver like this. sometimes it buzzes sometimes if just off charge it runs and it always runs on mains, but after a day or so, it will either oscillate then stop or just jerk and stop. One feels one ought to be able to go in these devices and tweak a control to allow more voltage drop at start up, but I'm its not that simple.

In the old days things were easy, if it started to last less long after a charge,you knew the batteries were duff but clever circuitry now keeps these things running once started at full speed even as the batteries die. Its only when this point is reached as above that things show up. Too bloody clever for their own good. Of course the same symptoms can be caused by brush and commutator wear. Tis the throw away society. You cannot even buy a new one and keep the old one for spares as after a few years the design has changed and nothing is the same. grumble. Brian

[The Natural Philosopher]

You are in deep trouble.

It almost certainly is not a normal brushed motor but a brushless motor.

3 phase with phases generated by clever software on the motor controller card.

It MAY be just a bit stiff - starting torque is pants. More likely its lost a winding or one of the fets has popped. Seen this many times on model aircraft controllers.

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