Siglent 804X knob/rotary encoder

[muriloalvares]

Hi guys,

so I JUST got this 804X and the next morning I find the knob on the floor 

seller offered to refund and all, but I really need this scope for a project and they don't have any in stock, so I was wondering if this is repairable? At first I thought it was just glued in, but then realized it is a plastic shaft that also works as a button, so I am guessing it just can't be glued back? Should I try to source the encoder and replace it? Is it a difficult job?

[Doctorandus_P]

Looks like a metal shaft to me. My own SDS1104X-E also has metal shafts on the encoders. The caps can be pulled quite easily from the shafts.

It is repairable. You could drill a hole in the shaft, put in a thinner metal axle and then glue it together with epoxy, but it would be a nuisance to do this. But a more mainstream (and simpler) approach is to replace the whole encoder, or maybe even replace the whole button board. (If that's sold as a spare part).

[2N3055]

You can operate timebase wit touchscreen, mouse,or via remote control.
Do not pass on the oportunity to replace it for brand new one for short term goals

[tautech]

Hi guys,

so I JUST got this 804X and the next morning I find the knob on the floor 

seller offered to refund and all, but I really need this scope for a project and they don't have any in stock, so I was wondering if this is repairable? At first I thought it was just glued in, but then realized it is a plastic shaft that also works as a button, so I am guessing it just can't be glued back? Should I try to source the encoder and replace it? Is it a difficult job?

Welcome to the forum.

Darn what bad luck. 

Take up the offer to have it replaced and keep your warranty.
It's a full strip just to access the encoder just to find its Pt# so for now to get on with your project connect a mouse to it to be able to use the timebase or you can use touch until your supplier gets them back in stock.

[eTobey]

Are you sure, that this is a plastic shaft?

[TUMEMBER]

Really? This isn't an April Fool's joke?   
I don't believe that in such a "renowned brand," the encoder shafts are made of plastic, and not at least of "shitty" aluminum.
I spit on my monitor, now I have to clean it out of chokeberry juice, and it's no easy task. Even the Rigol DHO 804 doesn't have such faults in its "set of stupid faults."

This teddy bear lost his eye...oh my god 

[DaneLaw]

Bummer, though almost looke there is pry-marks that continues, down into the materiel, which I guess is plastic from OPs feedback
If this wasnt a new unit, I would guess somebody had tried to remove the knobs, perhaps for some better ones.
- as the native ones do leave a lot to be desired, these cheap-looking grey plastic knobs, but they suit the purpose..


Click for enlarge

[2N3055]

Why are people talking about plastic shafts ?
It is clearly metal shaft, from pictures, and I checked on the scope...
Rough surface is crack texture on metal.
That encoder had hefty wack to break such....
 To remove the knob there is no need to use pry bars. You just grab it firmly and pull..

[Martin72]

so I JUST got this 804X and the next morning I find the knob on the floor 

We've all been there: you wake up one morning and find a broken button with its contents spilling out on the floor....

Why are people talking about plastic shafts ?

I've never seen a rotary encoder made of plastic.

[2N3055]

We've all been there: you wake up one morning and find a broken button with its contents spilling out on the floor....

 

I've never seen a rotary encoder made of plastic.

I did, on consumer electronics. And if done from carbon or glass reinforced nylon, it will be tough and very strong.
But here it is not the case. So I am simply correcting wrong facts.

[newbrain]

I've never seen a rotary encoder made of plastic.

Really?
I opened my switches/encoders drawer and about half of them have a plastic shaft. And they are Alps, from Mouser or DK not AliExpress catch of the day!

BTW: The SDS804X HD has metal shaft encoders for the ones with detents (Vertical and Horizontal), and plastic shaft ones for the ones without (the other three). The OP's one (Horizontal) is metal - at least, if it matches mine.

[DaneLaw]

I've never seen a rotary encoder made of plastic.

Plastic shafts on rotary encoders are quite common and come in various models.

[Martin72]

Thanks, but I know those kinds of encoders exist...
I just didn't see them on the devices I used to own.
I should have phrased that more precisely.
But neither a plastic nor a metal shaft just breaks off on its own, overnight.
In both cases, brute force must have been involved.

[mawyatt]

Yeah, that shaft just didn't break and fall off overnight. Likely it was broken off by a drop or something dropped on it, maybe crushing the knob. Then the shaft was glued back on and another new knob added.

A careful look at the shaft under a microscope should show signs of any glue if that were the case.

Best

[gamalot]

I've never seen a rotary encoder made of plastic.

Pick any Keysight or Tektronix instrument, say, an oscilloscope, and chances are the encoder shaft is made of plastic.

[gamalot]

I think it's quite reasonable to assume that a 6mm cast‑aluminum shaft could break due to manufacturing defects.

---

Just noticed that the fracture in the picture from op's post looks to be less than 3 mm in diameter. 

---

My bad, it looks more like a zinc alloy casting rather than aluminum.

[eTobey]

Likely it was broken off by a drop or something dropped on it, maybe crushing the knob.

Since the feet of the Siglent are very poor, the scope might have been moved (while plugging something in the back), and therefore the feet folded in, dropping the scope. A little object underneath the knob, and the day is ruined. 

[2N3055]

Likely it was broken off by a drop or something dropped on it, maybe crushing the knob.

Since the feet of the Siglent are very poor, the scope might have been moved (while plugging something in the back), and therefore the feet folded in, dropping the scope. A little object underneath the knob, and the day is ruined. 

The feet are not solid, they are foldable.
They will fold if you push them in folding direction.
It is small and light scope, you need to hold it with other hand when plugging BNC in the back or front.
I have Keysight MSOX3000T and it has same type of feet that will also fold if you do what you do to them too.
They are not mean to be used that way.

There is zero chance for that particular knob to be broken if you flip scope that way. There are BNCs (with probes?) and then a one row of knobs below that. And that knob is same height as others in the middle.
And they are not that soft. You can safely put scope on its face and nothing will break. In fact, when you are disassembling the scope you put it right on it's face and it is fine.

[MathWizard]

So how hard is it to get inside these and other Siglent scopes ? Is there any desoldering of shields, or is it just screwed on (besides maybe the most sensitive areas). I've taken apart some Tektronix scopes, I guess I should look for a Siglent teardown video.

The 'general purpose knob' on my 824XHD, feels scratchy compared to the ones on my other Siglent scopes. I guess it's just the plastic grinding, but maybe there's debris in it, or maybe it also took a knock at some point.

But it's too close to the warranty period for me to worry about checking out that pot/knob. But If it's actually the same as the one on my 1204X-E, I'd swap them.


LOL I forget about Zinc, and there's even an old educational video on Zinc that says it happens.

[tautech]

So how hard is it to get inside these and other Siglent scopes ? Is there any desoldering of shields, or is it just screwed on (besides maybe the most sensitive areas). I've taken apart some Tektronix scopes, I guess I should look for a Siglent teardown video.

The 'general purpose knob' on my 824XHD, feels scratchy compared to the ones on my other Siglent scopes. I guess it's just the plastic grinding, but maybe there's debris in it, or maybe it also took a knock at some point.

But it's too close to the warranty period for me to worry about checking out that pot/knob. But If it's actually the same as the one on my 1204X-E, I'd swap them.

Full strip down on most models to gain access to encoders.
Straightforward enough but not a 5 minute job.

For your 824X HD the encoder knob might be just pressed on too far and binding against the front panel....pull it out just a tiny bit to clear any possible bind.