Author Topic: Keysight to launch new oscilloscope  (Read 3780 times)

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Offline Wuerstchenhund

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Re: Keysight to launch new oscilloscope
« Reply #50 on: April 20, 2020, 01:27:19 pm »
Hobbyists can learn an awful lot from fixing their own test equipment.

Sure they can. As they can when fixing any other complex piece of electronics.

The older stuff generally has comprehensive manuals, often with theory of operation and circuit diagrams that makes it possible to learn from them.  I would say the markedly poorer documentation is the main "failing" of newer equipment.

Not everything old has "comprehensive manuals", in fact for a lot of old devices documentation is actually pretty poor. Quite often you have to re-construct the schematics from following traces and investigate to find out what specific components do.

And it's not true that modern equipment is necessarily less well documented, just that often the documentation is not freely available (which isn't different back then when service manuals were often optional, paid-for items that were only given out to dedicated repair facilities or calibration labs).

Many modern instruments still have extensive service documentation, which includes Theory of Operation as well as schematics. And even for cheap instruments like a Rigol DS1052E, a lot of documentation can be found with the component manufacturers.

But yes, reading manuals can be tremendously instructive, even if you don't own the actual instrument.
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Online filssavi

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Re: Keysight to launch new oscilloscope
« Reply #51 on: April 20, 2020, 10:45:23 pm »
Sure, there is some survivorship bias involved (for example, most HP 8xxx pulse generators were garbage IMO) but with the throwaway instruments they make nowadays, hardly anything will be left in 40 years.

Either because configuration from PLD or microcontroller EPROMs leaks empty and no way to recover. Or it looses calibration and no public info on how to calibrate. Without schematics, even something simple can fail and you can't repair, because you don't realize it's broken, without the insights a good schematic provides. So why no schematics, service and calibration info now, if I pay 10x the price of a chinese instrument?

The better scopes/logic analyzers back then were all modular, Tek 7k, 11k, HP 54750..., makes an instrument much more versatile and it's simple to replace the frontend, once something breaks down. Makes diagnostics simpler as well, than the 1board garbage we have nowadays. Why not today, make 1 good instrument with different plugins instead of 10, each artificially crippled in a different way? And split things up onto different boards, so things can be tested by swapping them. Once a moderately complex board is identified as broken, parts level repair usually isn't that hard, in case the manufacturer would provide the parts.

Funny how you rail against EPROMs that leak, I guess you must be driven insane by old boat anchors with what amounts to a suicide timber built in (battery backed sram for calibration data since flash and EEPROM were not around)

Also I think you are projecting your ideas onto the designers, I suspect each block had his own board mainly because you could not do otherwise with the technology of the time, I would bet whatever you want that given the choice they would have integrated as much as possible just like today, as the less connections you have the better performance you get repairability is just a side benefit.

Also I would argue that all the documentation and repairability features that were indeed designed in were a necessity due to much lower reliability of components and assembly techniques at the time, nowadays stuff is so reliable that there is no need (apart from PSU failures, the only way to damage. Modern scope is by blowing the inputs, otherwise it will continue to work until obsolescence)

As for modularity it is just not needed, a single basic low(ish) midrange range scope (lecroy HDO4000) can probably replace half a rack of 1970s boat anchors for most jobs
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Offline CRTbrain

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Re: Keysight to launch new oscilloscope
« Reply #52 on: April 28, 2020, 12:49:05 am »
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