About the rotary ON-OFF Switch of Naim NAP 140 : feel little loose


I would like to ask about the ON-OFF switch of the Naim NAP 140.

After several years of use, does it feel a little loose when it is rotated (can it be turned a few degrees) before the switch sounds “click” to ON and “click” to OFF ?

I want to open the knob, to open it, what screwdriver is needed ?

thank you

Assuming it’s a Chrome bumper unit, you’ll need a miniature screwdriver - flat head IIRC. loosen off the locking grub screw then just pull the knob off the shaft. Reverse the process to re-install. Make sure you don’t over-tighten as the plastic can get brittle with age and split or break.

Of course, it may be that the switch is worn, in which case it should be replaced when the amp is next serviced.

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If the rotary switch has been worn it doesn’t matter as long as it functions properly.
But is there a possibility that the knob locking bolt does not completely press the switch shaft?
I’m just curious, but I will do everything carefully

See what I wrote here, it applies to the on-off knob:

I am guessing the screw is a little loose, and there is a small part of the shaft that is worn which allows a little movement.


Yes you right

so I conclude that the rotary switch rotation for ON-OFF or vice versa is indeed lightly rotated, because of the characteristics of the rotary switch like that

regardless of whether there are bolts that are not dragging or not, the rotary switch’s working characteristics are like that

I tried to open the knob of the NAP-140 with the following screwdriver, but I am not sure if this screwdriver is correct. The flat width of this screwdriver is about 2mm, is this enough or not wide enough?

I think that will be the right size…

This is what I use, and it measures just over 2mm…

You have to make sure the screwdriver is properly fitting the slot of the screw and not ended up past the screw and wedged between the screw and the plastic on the knob.
Make sure the screwdriver is entering the hole central and heading for the centre of the knob, hard to explain but I think you will feel it when it is right.

And of course once the knob is off you can look and see how to fit the screwdriver for next time!!

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I see that the diameter of your screwdriver looks too big compared to the diameter of the hole where the fastening bolt is, is it not advisable to use a smaller screwdriver diameter of the screwdriver neck that goes into the hole in this knob?

I don’t have a 140, but in general it seems advisable to use a screwdriver that fits into the hole :slight_smile:

However, what’s up with the hub, is this broken? (If so, make sure that tightening the screw does not put too much stress on the tear and does not make the gap wider)

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The picture is a close-up, and even though it looks big, the blade passes through the hole ok.

In the picture of the back of the knob you can see the problem of age and over-tightening, and I filled the part of the knob shown, with some plastic just the right size, and placed as shown to strengthen the part that encloses the shaft. Mine may well have had a similar crack that I was keen to strengthen, I cannot remember exactly, but this seems familiar.

Can the picture of the back of the knob be posted without the green writing as it will be clear to see how the screwdriver must fit the screwhead and not slip past.

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Not wishing to labour the point, but I did this…

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not damaged, only the bolts are not tight enough, so that when the knob is turned, the rotary on-off rotates a little too

I understand this, but if the hub is broken, the screw may not be able to tighten it on the bolt if the gap opens

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the picture is not a knob, I am just a description of the position of the tightening bolts where, I can’t open mine myself because I don’t know what the shape of the fastening bolt looks like, it looks like using a flat screwdriver with a width of 2-3mm

Oh, thought it was yours

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