Cant decide on a Keysight Oscilloscope

[Bud]

EDU series is slower and I never tested it "unlocked" so cannot say on this part.

EDU is the same hardware as the respective DSOX model, with some parts unpopulated. In fact it has the same PCB. When modded, it exceeds in features the stock DSOX and is the best bang for the buck ever.

[kmoonwalker]

The service manuals of all the old HP equipment (and most other brands) is freely available. and it has a wealth of information for anyone wanting to learn circuit design. Some parts of those meters are also described in TaoE. And it makes these meters easy to repair (as long as it's not one of the custom IC's that is broken).

A bunch of years ago Dave had an interview with someone from keysigh and that guy gave some reasons for not making service manuals available for the newer stuff anymore. I think it was something like "No user serviceable parts inside", and this smells like the excrement of a male cow. If there were "no user serviceable parts inside", there would also be no objection to release the service manual, it just would have a lot of "non replaceable parts" marks. There is plenty of analog stuff that can break and would be perfectly repairable, and the real reason probably is the same as always: Marketing figured out they can make more money this way for less effort.

Unfortunately they're not alone in this. Does any manufacturer of modern test equipment still release service manuals with schematics?

sometimes they do but not often and usually if so they rlease for two generations back or something

Problem is that with nowadays software and x-ray we are able to do pretty fast reverse engineering

In the past it was lot more time necessary for that.

Nowadays you see chips, download application notes and by lazyness, comfort of using something proven or speed of making product most is following those notes so you just place the puzzles in place then what is usually problematic is some firmware protection
Also sometimes even looking at how some part of device was made by competition can greatly help overcome troubles at hand pointing smart head in right direction xD

But they usually do not give service manuals cause competition would be able to catch up way to fast

Another important reason is partially what that guy told you -> in most cases with complex metrology equipment we are simply unable to get proper equipment and references to properly cal and evaluate some more complex things - we can go close enough for our needs but most of us is unable to have some fancy things or could afford like one of such fancy things.

Example: I could perhaps get some super accurate resistance standards but other than for cal or check of meter from time to time it is better to spend those (few k$ at least) on some good soldering equipment, some better scope or even a decent 6-7 digits DMM cause that stuff you will use frequently or more often that such standards...
So I got some years ago small number of reasonably stable precision resistors for 50-80 USD and measured them with such luxury LCR at university, written on each exact value and... they usually are staying at friends company cause I need em perhaps two times per year and he makes way better use of them on production line equipment periodic tests to tell if he needs to send them to cal or not or in case of doubt.


Ask yourself this - with all documentation available for revered HP 8 digits DMM and many decades passed since its release nobody made a new version.
Why? Perhaps it is as good as we need for now and new design waits in a drawer for better days. Or tricks implemented then are stil giving a good headache for next gen designers. Or cost of making it would be enormous.

[kmoonwalker]

EDU series is slower and I never tested it "unlocked" so cannot say on this part.

EDU is the same hardware as the respective DSOX model, with some parts unpopulated. In fact it has the same PCB. When modded, it exceeds in features the stock DSOX and is the best bang for the buck ever.

but can it be unlocked with reasonable cost/work amount to level of 200 MHz and 200k wfm/s speed?

[tggzzz]

I'm looking to get my first oscilloscope and I can't decide between the following 3 options. I'm mainly planning on working on i2c, spi, Rs232 and maybe usb 1.1 if I need to debug issues.

A scope is an analogue domain instrument, so use that to ensure signal integrity, i.e. voltage and timing limits are observed. If you know signal integrity is OK, then you don't need a scope.

Once signal integrity is assured, you will be operating in the digital domain looking at messages. So flip to using a digital domain tool for that, e.g. a logic analyser, a protocol analyser or printf().

Simple LAs and PAs are remarkably cheap compared to scopes, and can do things scopes can't do. Look for ones that don't start capturing until a specific combination of inputs or message is received.

[Bud]

EDU series is slower and I never tested it "unlocked" so cannot say on this part.

EDU is the same hardware as the respective DSOX model, with some parts unpopulated. In fact it has the same PCB. When modded, it exceeds in features the stock DSOX and is the best bang for the buck ever.

but can it be unlocked with reasonable cost/work amount to level of 200 MHz and 200k wfm/s speed?

For 200MHZ it is required to replace several parts in the input section ( cost is very reasonable, parts available). Firmware update effort is close to none, just run a update from the GUI from a USB stick.

Edit: you do need SMT soldering skills for the hardware update part.