Oscilloscope Recommendations - Affordable yet repairable?

[MT]

Circularly?  Perhaps Analog Devices called up Siglent to point out that stick-on heat sinks on top might not be all that helpful for a device with a large pad on the bottom.

Perhaps, who knows!

[tautech]

Anyhow Tautech already confessed Siglent swapped fans to more silent ones in other units.

Confession ? Actually a fact !
Why shouldn't Siglent improve models if/when they can ?

SDS1202X-E is in a lower class of performance to 1104/1204X-E and these later 4ch models require more cooling.
Shoebox size entry level scopes with such capability and feature set need be adequately cooled so require a decent airflow.

IME handling many of both these models there have been slight changes over the years and for the 4ch X-E's a lower consumption fan has been fitted in the last year or so.

[kcbrown]

"Characterization" here means that they monitored the temperatures of the heat-generating components to ensure they didn't overheat.  Apologies for any confusion.

Easy to say claim now isn't it? This is one of the things you said previously perhaps in case you forgot:

The fan that is supplied with the unit has already been characterized by the manufacturer to cool the internals to levels that allow for reliable operation.

Sounds like you talk about the fan alright which makes rest of your novel uninteresting to read more of a word salad defense, sort of.

Which is why I apologized for the confusion.  If that's not good enough for you then tough.  Deal with it.

So obviously moving goal posts not even considering the thermal specs of the HMCAD1511, with your word salad Tautechs spin down your fan with series resistor suddenly
dont count according to your preaching of "engineer worth his salt" "good engineers build in margins into their designs" etc, etc, and gobble ,gobble.

Huh?  Tautech was referring to what an individual can do with his scope after the fact, not what the manufacturer was considering doing!  An individual's environment can easily (and likely will) differ from the warmest environment the scope is specified to be able to operate reliably in.

An individual can replace the fan with something quieter if he so chooses.  It's his scope, he can do with it what he wants.  I was only describing in my original message why I am personally reluctant to replace the fan with something that flows worse than what the manufacturer supplies.   That's just me.  Others can do what they want.

Anyhow Tautech already
confessed Siglent swapped fans to more silent ones in other units.

Yes, in other units.  It's likely Siglent received enough complaints about fan noise that they switched to a quieter unit with less airflow in the SDS1202X-E because they were able to actually get away with doing so.  That doesn't automatically mean they can do that with all their models, and why in the world would you think otherwise?  None of this negates anything I said previously.

So why didn't Siglent just go with that quieter model in the SDS1202X-E from the start?   Presuming they originally used the same fan in the 1202X-E as in the 1104X-E/1204X-E, likely because they already knew that the cooling demands of the 1104/1204 were greater and, thus, that the fan from that model would be sufficient for the 1202, and by selecting the same fan they would get better economies of scale, if nothing else.  Obviously they would have tested the thermals with the 1104/1204 fan in the 1202 just in case.

[tautech]

So why didn't Siglent just go with that quieter model in the SDS1202X-E from the start?   Likely because they already knew that the cooling demands of the 1104/1204 were greater and, thus, that the fan from that model would be sufficient for the 1202, and by selecting the same fan they would get better economies of scale, if nothing else.

It's likely they just used the same fan fitted in the older SDS1102/1202X. They ran an ARM uP whereas X-E run the more powerful Xilinx uP which for all I know could run cooler. AFAIK the older X models run the same ADC.

However the X model did have a slightly larger enclosure, 8" display and had an internal AWG so needed the higher airflow of the earlier and noisier fan.

[james_s]

Manufactures upgrade products all the time. Back when I worked at a place that made hardware we regularly revised models, replacing components like fans, RAM, hard drives, etc. Usually for cost reasons but it could just as easily be done to make something quieter or to correct premature failures.