The Rigol DHO800 Fan(boys) Go Wild

Testing the thermal temps with and without a fan on the new Rigol DHO800 oscilloscope.
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[@electrodacus]

Seems like there is a large thermal resistance with those thick thermal pads. They just made the best choice possible considering the ~35W cooling requirements. A constant speed fan with the speed selected to offer sufficient cooling in worst case +50C ambient temperature. Based on your measurements I expect that die temperature of at least one of those IC got to 100C maybe 105C while heatsink was at around 75C that means about a 30C difference between heatsink and die so total to ambient about 45C so in 25C ambient the die will be at around 70C so fairly normal and even with extra 10C ambient is still OK at 80C die and with the limit 50C ambient 95C die witch is at the limit but still OK. With a constant thermal load as it is the case for this scope a fixed speed fan is the best cooling solution as intermittent thermal control fan will not make any sense. It will be quiet for a minute or two and then you need higher fan speed for many minutes to reduce temperature. On top of that the thermal cycling will not be good long therm. For those that are bothered by the noise of the small fan the best solution is a 80 or 90mm fan installed outside using some 3D printed case and supplied by the 8V internal fan connector. I will see how mine is but I will probably be fine with the original fan.

[@SeanBZA]

Those thick silpads are not too bad heat transfer wise, though you could also improve things by removing them, and placing a better one, or 2 thin ones and a copper shim to spread heat. Heatsink best improvement would be to take it and beadblast the back, to get it clean, and increase surface area, then place a cut shield to make it act like a duct, and space that fan up off the board by 2-3mm, so as to improve airflow from it.Axial fan turned into radial fan is not efficient, so either raise it or get one designed to flow air radially. Plenty for the graphics card market that would mount there, and the cards all have a cover to direct airflow over the fins.

[@mrnmrn1]

A thermally controlled fan would make sense, if it measures the air intake temperature instead of the chip/heatsink temperature, to compansate for varying ambient temperatures. And they should have used a 3-wire fan to shut down the scope if the fan dies. Or a temp sensor on the heatsink for the same purpose.

[@electrodacus]

@@mrnmrn1 air intake temperature is not relevant as there can be quite some variability in the thermal resistance between different units as well as over time as thermal interface may degrade. They already know IC die temperature so that is not a problem. As seen in this video the unit shut down safely when one of the IC's got to temp limit guessing 105C. Not having the third wire makes it simpler for people to add any fan with larger slower spinning blades.

[@Electheo]

@@electrodacusI have a dho900 and lil concerned about the heat (and smell). So might consider modding it. What did you end up doing?

[@electrodacus]

@@Electheo I had no time to do anything with it so it is still original. The smell is still there not sure if it will ever go away. I have not used it that much a few hours for a few days. You can see my last vvideo and main reason I needed a 12bit oscilloscope. Amount of heat is probably OK despite me not being to happy but the smell is annoying as I was hoping it will go away after some time and there is no real solution for that.

[@mihaiachim5299]

if it were up to me, I would install an external fan with a protective grill attached to the vesa mount. You can also keep the vesa mount but you need 4 threaded rods and 4 elongated nuts …

[@Stefan_Payne]

I don't understand why they didn't go with a bigger fan and went with the small 50mm fan. As for the style of that fan: It wasn't uncommon in old Graphics cards, so around Radeon 9800 or so, something like that, up to early 2000s

[@ahmedalshalchi]

Because the stupid idiot customers are always being attracted by thin depth instruments just like slim skinny fashion models so don't blame RIGOL but blame the stupid market requirement ...

[@der.Schtefan]

Probably wanted a smaller fan to have a smaller form factor as part of marketing

[@Stefan_Payne]

@@der.Schtefan You could have used a 60x10mm (or x15mm) fan, which would have been much quieter while retaining the form factor...

[@AKAtheA]

ah, the 9800...one of the 2 GPUs I actually burned my fingers on

[@ColdWarVet607]

Fan choice is based first on meeting thermal performance then by cost, availability, reliability. I would think noise was on the list but not high up. This scope had a double design/manufacturing cost factor in it. In reference to previous products it greatly increased the design complexity/performance and secondly it drastically decreased the cost. Thats cost to Rigol and the consumer. So cost savings on the fan, whatever they be was very important. Alot of people crawled over alot of data to try and figure out how to design and manufacture this scope, no easy task. Cost is not only the raw cost of components but every last little step in manufacturing. I did Hardware Design on Fault Tolerant Servers all my life and I can tell you as amazing as the electrical design seems, the manufacturing of products like this is a pretty amazing process as well, not only do once but to do over and over in the high qtys they deliver. Theres a tremendous amount of analysis, test & validation that goes into manufacturing. The manufacturing engineers are the unsung hero's of electronic products. So....yes... the cost of the fan was significant and they were probably happy to trade of a bit of sound to me the overall project goals.

[@patrickwasp]

a bigger heatsink would help. Your Rigol Was So Preoccupied With Whether Or Not They Could make it that thin, They Didn’t Stop To Think If They Should.

[@joaquins90]

A slim 80mm fan with a grid at the back and you have your thicker and silent mod.

[@oswaldjh]

Mount a computer case fan on the back of the scope case and run the power cable thru the vents in the case. Larger fans turn slower and make less noise for the amount of air they move.

[@elkiaora]

I was thinking the same

[@Stefan_Payne]

That heatsink style looks familiar... Something like that was, back in the day, used on Geforce 6800 series reference cards.

[@EEVblog2]

It's completely custom. The actual radial fin desing is not new though.

[@felixcosty]

Thanks for the video. Use the Visa mount to add a better fan to the outside. Noctua fan on low rpm would make no noise.

[@universeisundernoobligatio3283]

Get a 120mm quiet CPU case fan, cut out some of the back grid, screw it to the back, now it will be quiet and very cool..

[@dglcomputers1498]

Behringer did something sensible with their Deepmind 12 synth, it has a small fan to maintain temperature stability in warm environments but the synth will no be damaged if it's turned off, because of this they added a fan speed setting in one of the menus that can be turned all the way down to off. Want it to be silent and your studio is not that hot then turn it off, want help with temperature stability in a warmer environment then you can turn it on as fast as necessary.

[@brianhginc.2140]

I'm curious with the 12bit precision , having a fan directly mounted on the back of the heatsink & circuit board, can the 12bit front end's ceramic cap's microphonics actually register the mechanical vibrations of the fan? I guess you would need to quickly run the scope with the fan off, then again normally to see if there is a change on the minimum noise AC vrms.

[@Mr.Leeroy]

it is a weak ass almost weightless fan at relatively low RPM, I highly doubt it

[@vladshmit]

@@Mr.Leeroy Oh boy, it's an entry-level scope, you don't expect it to be fully compliant with the high instrument standards )))

[@feluke8396]

I don't know why they didn't go with centrifugal fan and other heat sink design. That would be almost silent and provided way better cooling.

[@AndrewJones-tj6et]

Be great if Rigol also sent you a DHO914S with the logic analyser and arbitrary generator to review. Really curious how these work on this smaller form factor scope and how good is Rigol's implementation.

[@Damien.D]

For those really annoyed by the little screaming fan, a silent bigass one can be bodged on the VESA mount with wires going thru the vents.... Also, having tickered with PC cooling since my early gamer age, I can tell that the heat sink design is not perfect. The flow of such fans is downward, to the flat plane, and they are expecting the airflow to go laterally, but since there is no plate on top, it just bounce back and swirl all around. A real fix is to add a plate to transform all theses spiral cutouts into channels and use a "squirrel cage" radial fan (common stuff on laptops). With a duct on the back so fresh air is nicely sucked in and hot air guided only on the heatsink.

[@tapravdec]

This axial fan in such configuration is a waste of airflow.. It realy should be a radial type with closed fins on a heatsink.

[@JasonSobell]

70°? That's child's play. I just received my scope, and after an hour of running it I discovered the fan had stopped running when I burnt my finger on the signal generator BNC. A quick thermal camera check show's it's reached 81.6°C at the top rear air vent, so presumably way more than that internally. I'm waiting for support feedback, but I'm guessing it's a replacement job. At least we now know it can go volcanic without obvious damage.

[@pcfreak1992]

What if you remove the small fan and put a 120mm computer fan on the outside using the VESA screw holes? Is the airflow good enough that way? For a desktop deployment this should be fine and in theory much quieter.

[@jcbarros71]

Almost a barbecue in name of science. Ufff!

[@DrakkarCalethiel]

A blower with the right dimensions would not only cool better, but also make way less noise. A laptop fan might do the trick nicely.

[@SeanBZA]

Fan could probably benefit from having a flat plastic shroud over the heatsink, to get the airflow to move over the fins more efficiently. Would probably reduce the temperature by 5C, and if you had a thin layer of felt over the non airflow side it could do a bit of noise reduction in the case as well. Reduces clear space by 2mm, so will not affect the airflow much. Plus you could go for a similar mount radial flow fan there, which would provide much better airflow, using a laptop fan unit instead, or mount the existing fan up off the heatsink a bit more, using a 3d printed 2mm spacer, to actually use the airflow from the whole fan unit, not just the outer 10% of the blades.

[@Damien.D]

yeah that the correct way to do it.

[@Chris-ut6eq]

If the fan really bothers someone, they could use the vesa mount and 3d print a holder for a larger 80mm fan which would get much more airflow with less noise and of higher airflow. This would require good testing.

[@twilliamc3]

Could you use the VESA mount to 3d print a mount for a noctua fan externally?

[@EEVblog2]

Yes.

[@tinygriffy]

(same thought, although any old 100mm fan would do right ?) .. and a battery pack while at it ^^

[@AmauryJacquot]

how about mounting a large noctua fan in the back as a replacement ?

[@WacKEDmaN]

LOL good job killing that Dave! .... more repair content for the main channel i see! :P

[@franke5478]

I would remove some of the fins to add a lager fan with 60 or 80 mm.

[@kalli71]

love this - world goes crazy over the fan. It could play 'La Cucaracha' for all I care if I had one of those

[@EngineeringAllAround]

Full review, please!

[@Evergreen64]

Rigol just listed this scope on their US web site today.

[@infango]

there are 4 brass inserts for screws on back, can you mount 90mm or 120mm high static pressure fan ?

[@miqueles5783]

Bigger fan - lower noise. I don't understand, why manufacturers doesn't understand that low audio noise is a important factor

[@covid-19warrior36]

Dave, you should get a kickback from Rigol 😁, as I just bought a DHO804 based on your review.

[@ErrorMessageNotFound]

If you weren't going to be VESA mounting the thing you could mount a large case fan outside to the mount holes. It would probably be much quieter.

[@tannerbass7146]

Man I really like the new design

[@QsTechService1]

A couple macbook fans You can probably fit underneath the heat sync

[@RoderikvanReekum]

Can you install a very low noise fan instead, there are some great fans available. Oh it is built in to the heatsink.

[@martinkuliza]

0:36 Please note that Dave's Air Con is Accurate to 12 Decimal places and has a Resolution of 15 Digits with +/- 2% Tolerance LOL

[@Chris-hy6jy]

Why they didn't just make it a bit thicker and put a larger fan in is anyone's guess.

[@JAKOB1977]

surprised to see that the fan is on 24/7 while in use.. and not temperature depended. another Android based scope, like the Micsig tablet scopes.. those consumes about 30watt, when running them from USB-C power delivery 12v powerbanks, and peaks around 35watt, when also charging the internal battery, but here the fan is mostly off, and only kicks in, if its reach a certain temp- supprised to see the heat go that high without an active fan with that relative beefy heatsink.

[@MatthewSuffidy]

You would think they designed it to shutdown on overheat because that fan TOTALLY looks like it is going to crap out after a while.

[@deadmanwalking6342]

Put a big ass fan into the VESA mount holes, you can still use the vesa mount.

[@szabolcs__]

It would be smart to put a sensor or sensing on the fan , if its not working, turn off the scope.

[@jamesc7400]

So when the fan dies, there is a risk that the scope dies. Is there an overheat warning or shutdown ? Another thing that I have been wondering about is the read/write lifespan of that glued in SD card from your previous video and how long that will last.

[@joaquins90]

It did shut itself down in the video, and survived, so I guess it's fine... But if the fan is annoying, you'll likely notice it before, unless it's in a noisy environment. I'd stuck a silent fan from the outside with a grid, if it was really a problem for me, but I only have the scope on when running some test, which is not often enough to get me through the trouble, even if it was an annoyance. It seems like the airflow would be good blowing air in from the back... Slim 80mm noctua and a grid?

[@EEVblog2]

You'll (not) hear it die

[@StippedGearhead]

I just got my DHO814 and I cannot even hear the fan. Not sure if they changed it for the production version but it's nearly silent.

[@Artesian_Turkey]

Way back in the day, computer modders started volt modding fans in their cases for lower noise. It was typical that fans could hvae issues starting up about 7v, and very few had issues at 8v, hemce the odd voltage. Personally, i think rigol should refine their heatsink to accomadate at least a 60mm+ mounting fan. At 8v, it should be quieter than a 45mm. They could also usse a taller fan, but that would also increase the height of the heatsink without using a shroud, also pushing up the price point or complexity. Not a bad design, but needs work. Alternately, getting better performing pads ( i have no idea what Rigol is using or how it compares against other pads) could help a bit.

[@jonathanbuzzard1376]

The scope is IMHO targeted at the hobbyist market. IMHO 99.99% of purchasers would have preferred a 10mm thicker case with a standard 60mm or larger fan.

[@NICK-uy3nl]

Constant speed fan is not a good solution. Ideally the scope should have a variable speed fan based on the die temperature. With a PWM control and a MOSFET they can easily control the speed of the fan so that it is not so intrusive.

[@tomboxyz5564]

Constant speed is actually a good solution in this case, a fan running at constant speed is much less noticable than one that is speeding up and slowing down all the time. Also considering the power usage of that scope is pretty much constant, the temperature will be stable, at least relative to ambient

[@volodymyrzakolodyazhny7740]

Various speed fan is much more evil.

[@Mr.Leeroy]

VESA mount begs for adapter to 140 / 120 x 15 mm fan and run it at like 600rpm

[@tomboxyz5564]

The OWON TAO3104A that I use (100MHz, 4ch, single 1GSa/s 8/12/14bit tablet scope) has a little 30mm fan that can run at 3.3V or 5V IRC, don't remember now if it had a jumper or seperate sockets inside to change it, but I think it runs 3.3V default, it's quiet enough that you have to put your ear next to the scope to hear it

[@TD-er]

Hmm just running at a lower voltage without much fan control is a good receipe for failing when the fan gets older. It might need a higher current to start spinning when the bearing wears out or dust gathers and you may not be able to get enough current at lower voltage. It would be worse if they just inserted some resistor in series with the fan, but let's assume they just put in a voltage regulator set to 8V. Or do they ramp up the voltage when the temperature rises?

[@MrAwyork]

The fan and heatsink design will just make noise. There's not enough space between the blades and the metal. Maybe be able to put a big fan across the VESA mount. 1054 is loud too.

[@patrikfloding9185]

Yeah, it's a very suboptimal design.

[@gerykis]

It that a pro temperature probe what is plugged into the multimeter ? What type is it ? I might need one for my multimeter (Brymen)

[@Daveyk021]

Dave, Can you check the pulse width measurement and see if you can define the mid-reference points?

[@anshchawla566]

I wonder the thermals when its VESA mounted

[@danielberghout62]

Would you be able to strap a 120mm Noctua fan to the back using the existing vesa mount holes, maybe a nice 3D printed bracket to maake it all fit nice ?

[@oldman1944]

That boot time is brutal. Dealbreaker for me.

[@henke37]

At this price point it's something you will just have to deal with.

[@Master_zzz]

@@henke37 Nope. Other pro scopes within this price range do not have boot times this long. So pricewise it has nothing to do with it. This is just an android problem.

[@mb106429]

it is an axial fan with it's arse up against flat aluminuim; this is a centrifugal configuration surely ? .... is airflow is the objective?

[@Homer19521]

Just mount a BAF (big assed fan) on the outside & run it slow

[@tinygriffy]

3d print a CPU fan adapter for the vesa mount ? .. and a battery pack mount while at it ^^

[@RickB3n]

this new scope have a slow data logger (saving data on usb stick) and Bode diagram features, like Siglent ones ?

[@RickB3n]

I have the solution. cut the plastic on the back and insert (embedded) a 120 mm fan, for example, of a good brand.

[@stuartm5745]

I agree. I would use a Noctua NF-F12 120mm +12VDC PWM fan so I can vary its speed for the lowest noise with the highest RPM using an external potentiometer (900-1000 RPM is essentially silent at more than 3 feet). I make my own PWM controllers for less then $10/each but the Noctua NA-FC1 fan controller ($26 Amazon U.S. September 2023) is a good ready-made option.

[@RickB3n]

@@stuartm5745 The PWM controller is over the top. Since the power is constant (35W) it makes no sense to vary the speed. In computers it makes sense because the power varies continuously based on CPU usage. In my opinion, a resistor in series with the fan and an electrolytic capacitor in parallel to the resistor are enough, just to have more power if the bearing dries out when the fan starts.

[@RickB3n]

@@stuartm5745 Furthermore, having a component that generates "electromagnetic pollution" inside the oscilloscope such as the PWM controller is not exactly a wise choice.

[@tristankordek]

Thx 🙂👍

[@DavePoo2]

I have the previous model Rigol and it's a pretty noisy thing. I imagine that this new one is already better than the old one?

[@_SR375_]

would have been nice for them to use a noctua style fan

[@radarmusen]

expected it would have a temperature sensor so it would shut down not reboot.

[@ki4dbk]

Fun stuff, can you software mod that long boot time: jmp over splash screen vector.

[@radarmusen]

Maybe a Noctau could be modified to live in there.

[@patrickdemeyer2210]

What the emissivity setting on the Flir ?

[@TrevorsBench]

I hate fans in my test gear on the bench. How hard would it be to engineer this without fans? I think it's just lazyness on their part

[@309electronics5]

Bigger heatsink or better designed heatsink or just a less fast processor

[@fullmoon6661]

Next hack: Mill a new heatsink block and put a bigger fan.

[@benespection]

Gee Dave, you had my cat really worried that you'd popped a chip with that heat: kzbin.info/www/bejne/oISpq3WoaNOhmZY I don't understand why they always put these pissy fans on things. Maybe in a busy lab environment you wouldn't notice from all the other noise, but surely the cost difference to put a larger and slower fan isn't going to break the bank. Also a larger slower fan would make it less likely to make vibrations.. EEVBlog #855 + #983 ?

[@PetraKann]

Why would you want this unit to run without fan cooling?

[@EEVblog2]

No noise.

[@309electronics5]

I dont understand that a scope being somewhat expensive has such a bad cooling design that heatsink looks kind of rubish and the fan is rubish and it seems like its on full blast and not pwm controlled. And the boot time is a bit long (i know its android but its anoying)

[@patrikfloding9185]

In the 'scope world, this i dirt cheap. But, yes, it wouldn't have cost them much, or anything, to do this right.

[@ecospider5]

I had a dual Xeon workstation back in 2002. The fans were annoying so I took them off to see what happened. And it ran just fine with just the heat sinks. Definitely can’t do that with many things today.

[@vgamesx1]

I have an older APC smart ups rated for 1000w, has an annoying 80mm fan runs 24/7, as my PC only ever draws over 200w when gaming I unplugged it and works fine, generally reports a temperature a few degrees above room temp.

[@ecospider5]

@vgamesx1 Yes at that wattage it’s not surprising it worked. Especially if the other fans in the case were setup right so air still went through the power supply.

[@patrikfloding9185]

@@vgamesx1 It will cook the electrolytic caps, and shorten the lifespan. The solution is to run the fan at lower speed, as the last irritating RPMs contribute little to the airflow, but much to the noise.

[@vgamesx1]

​@@patrikfloding9185 It already runs at a low speed and goes faster when the UPS kicks in, the noise has nothing to do with it running too fast, it's just a low quality fan, even the transformer is very noisy in use, it's been going like this for over 5 years, on an already used 8+ year old unit, I'm more worried about the relay going bad since that's something that occasionally happens to similar units.

[@ivolol]

Why oh why can't they go with 80 or 90mm to get the pitch down? sigh

[@Poxenium]

chop out the inside of a noctua fan, a lot quieter

[@feedback-loop]

come on, Dave, do you really need to resort to clickbait like this? "DON"T do this!" - really?

[@EEVblog2]

You clicked, didn't you? It's very true though, DON'T do this.

[@SystemX1983]

"DO NOT TRY THIS AT HOME!" "Erm, what about in the Lab?" 😁

[@borisdg]

FirstD are not "unknown". They are pretty common in GPU market. They make good fans. Just like Sunon and so on.

[@alansmith4734]

Moon Fact: I am in the US and the way that I view the Moon would be inverted if I was in Australia! The Moon would be in the same phase as it is in the Northern Hemisphere (US), but it would appear upside down in the Southern Hemisphere (Australia)!

[@yoppindia]

Liquid cooled monster required.

[@Okurka.]

Missed the opportunity to put OnlyFans in the title.

[@leandrolaporta2196]

Geez that fan is a piece of crap, hundreds of those died on me, if my brand new DSO depends on that junk it will worry me the hell out, a big nono for me, enough not to buy that instrument

[@lasersbee]

If the Fan noise annoys you.... Go live in the woods..

[@Master_zzz]

Why would you go live in the woods if the noise of an oscilloscope annoys you?

[@patrikfloding9185]

It's not "annoying". It's stress inducing. The hearing is very sensitive just in the frequency band where these small fans make the most noise.

[@George-lp5qb]

Let's water cool it!

[@Okurka.]

Or use the Threadripper cooler he was trying to mount on a Ryzen 9.

[@309electronics5]

Just let dave team up with linus and watercool that bad boy like they alr did on a ti calc

[@stevenbliss989]

The crap thermal pads they are using have way too much thermal resistance. Sadly short of very expensive exotic pads, there is nothing better available :( An external LARGE thin fan is likely the only option ...i.e. use the external mounting screw holes!

[@MrMegaPussyPlayer]

5:56 How about to plug a 200mm on the VESA instead?