Rigol's New DHO800 Oscilloscope unbox & teardown

[Fungus]

I can't imagine other countries will allow the import of those power supplies. 12V into a USB-C connector is a big no-no. I hope nobody tries to use one to charge their phone.

That is perfectly defined. USB-C goes to 48V @5A (and some push 6A) nowadays.

Yes, but ONLY IF BOTH DEVICES AGREE TO IT. There's plenty of devices out there with USB-C connectors that only want 5V. Would you connect this supply to one of them?

It is all about detecting what kind of device is connected.

So tell us ... how does this power supply detect what kind of device is connected?

[wasedadoc]

The PSU PCB has provision for a common mode choke on the mains input but only wire links have been fitted. See near L1 marking.

[mawyatt]

The MHP-30 Miniature Heatplate uses a type USB-C but requires up to 60 watts, so obviously some extra communication between the Power Supply and Load.

Best,

[Azusa]

Rigol has stopped delivery DHO8/900 now because of the power supply.
i think they will replace each into they already packed up

[Fungus]

My translator says:

"Hello, Mr. Li, due to the problem of the DHO8900
adapter, the factory does not allow delivery at present."

[nctnico]

In the end it doesn't matter for as long as the PSU passes CE / FCC limits.

As long it does, exactly..
Does anyone believe that ?

Trace the PCB layout for a bit and you'll notice that this PSU isn't your bog standard flyback PSU design. It would be nice to get a better picture of the component side to see what it what.

[zrq]

Rigol has stopped delivery DHO8/900 now because of the power supply.
i think they will replace each into they already packed up

It sounds like Rigol got hurt by a corner cutting adapter OEM.

[ataradov]

That's really on them though. Even without opening it, just one look at the label and it becomes clear that supply is crap.

[wasedadoc]

In the end it doesn't matter for as long as the PSU passes CE / FCC limits.

As long it does, exactly..
Does anyone believe that ?

Trace the PCB layout for a bit and you'll notice that this PSU isn't your bog standard flyback PSU design. It would be nice to get a better picture of the component side to see what it what.

I'm not defending the PSU but would you care to elaborate why you say it is not a "bog standard flyback PSU design".

[nctnico]

In the end it doesn't matter for as long as the PSU passes CE / FCC limits.

As long it does, exactly..
Does anyone believe that ?

Trace the PCB layout for a bit and you'll notice that this PSU isn't your bog standard flyback PSU design. It would be nice to get a better picture of the component side to see what it what.

I'm not defending the PSU but would you care to elaborate why you say it is not a "bog standard flyback PSU design".

I looks like the big electrolytic is not across the output of the mains recitifier directly. Not doing this improves harmonics and power factor.

And there are a few other tell-tale signs that the designer of the PSU has thought about passing EMC testing. Look at the gate drive, snubbers and auxilary power filter components.

Ofcourse this is not a quality PSU due to cheap electrolytics placed close to heatsinks but I don't think it is a bad design at the core. Except for putting a USB-C connector at the other end without the ability to negotiate the output voltage.

[Martin72]

I looks like the big electrolytic is not across the output of the mains recitifier directly.

You could be right..

[wasedadoc]

In the end it doesn't matter for as long as the PSU passes CE / FCC limits.

As long it does, exactly..
Does anyone believe that ?

Trace the PCB layout for a bit and you'll notice that this PSU isn't your bog standard flyback PSU design. It would be nice to get a better picture of the component side to see what it what.

I'm not defending the PSU but would you care to elaborate why you say it is not a "bog standard flyback PSU design".

I looks like the big electrolytic is not across the output of the mains recitifier directly. Not doing this improves harmonics and power factor.

And there are a few other tell-tale signs that the designer of the PSU has thought about passing EMC testing. Look at the gate drive, snubbers and auxilary power filter components.

Ofcourse this is not a quality PSU due to cheap electrolytics placed close to heatsinks but I don't think it is a bad design at the core. Except for putting a USB-C connector at the other end without the ability to negotiate the output voltage.

Ah, I got the wrong impression from your original "not bog standard" post.  Possibly conditioned by previous posters showing the PSU little love, I interpreted your post as meaning it was certainly inferior to a standard design.  I wonder if a significant percentage of readers did likewise.

[AVGresponding]

I looks like the big electrolytic is not across the output of the mains recitifier directly.

You could be right..

How's that then? According to the silk screen the +ve rail is fed from the rectifier via a series capacitor. Does that really make sense? I'm betting it isn't, and the actual component in there is either a wire link, or a fuse.

[wasedadoc]

The yellow ellipse is around a wire link. The fuse (red box shape on top side of the board) is in the lower right corner directly above the capacitor symbol on the silk screen.

The capacitor symbol in the yellow ellipse is in the wrong place. The high voltage electrolytic pins are below and to the left. (The red and black magnifying glasses).

So, no real departure there from bog standard.

[Azusa]

Rigol delivery me a Lenovo 65W adaptor.It's made by Chicony.
I‘m curious of what adaptor they will provide when secondary batch.

[Azusa]

It looks fine with the lenovo adaptor.

[Fungus]

Rigol delivery me a Lenovo 65W adaptor.It's made by Chicony.

I bet the final adapter won't be as good as that one.

I'd have thought an off-the-shelf phone charger would be the best option but maybe they're incredibly noisy or something.

Maybe Rigol was counting on future supply-chain availability when they decided on the power supply and it hasn't worked out for their bean-counters.

Still, the 'scope itself looks awesome.

[nctnico]

The yellow ellipse is around a wire link. The fuse (red box shape on top side of the board) is in the lower right corner directly above the capacitor symbol on the silk screen.

It could be but I don't know for sure because I can't see it from the picture that was posted earlier.

[Martin72]

@Azusa:

Could you please post a pic from the top of the open supply ?
Thankyou..

[Azusa]

The original power supply,a flyback converter.The controller is OB2269CP.
The mosfet is 8n65 8A 650V.

[nctnico]

And we still can't see the one component we are looking for 
Please, just a picture from the top that shows ALL the components 

The soldering is pretty bad BTW. Can't believe a brand like Rigol delivers something like this with one of their products.

[Martin72]

 
Once again please, Azusa...

[TurboTom]

I bet that in the position with the "yellow-circumlined cap", an inrush-current limiting NTC was supposed to be installed. Since the OEM's ECAD probably doesn't provide a resistor in that form factor in the library, they just used a replacement from the caps library...

Since every safety and EMC relevant component has been omitted anyway, no surprise that this NTC has been replaced with a piece of wire as well. Use a high-ESR electrolytic of questionable brand (that also doubles as PFC...) instead and everyone's happy... 

[Azusa]

i just notice the C8 is a wire.... |

[Martin72]

So the electrolytcapacitor is directly to the rectifier connected, thank you Azusa.