Great thread thanks for sharing. Really makes you want to order an oscilloscope and some CPUs to putz around with.
Everything in computer science is such a rabbit hole, great field to be in.
Everything in computer science is such a rabbit hole, great field to be in.
It was the first 'real' scope I bought and I still use it a fair amount despite having upgraded to a Rohde and Schwarz MSO model. I've been amazed how much I use an oscilloscope after getting one, from measuring ripple on power supplies to diagnosing serial communication issues.
It's interesting how Rigol did the locking of those extra features. The unlock key for a feature set for your scope has to be signed by a Rigol private key using an elliptic curve signature system.
But they are only using a 56 bit private key. That was quickly brute forced, and key generators proliferated.
They used a good library for the cryptography stuff, and except for the short key seem to have used it well and knew what they were doing. This suggests that the choice of a weak key was deliberate.
Each family of scopes has its own private key. As few families came out with new private keys, Rigol continued to use 56 bits. When major firmware upgrades came out in existing families, where they could have easily changed to a longer private key, they kept the same 56 bit that was now widely circulated on the net.
It seems pretty clear that they are not interested in stopping people from free unlocking.
Any recommendations for learning resources that could help with understanding DC power supply analysis for non-EE types? While refurbishing laptops and working with microcontrollers I’ve run into some odd things where ruling out transient power supply issues would probably be helpful.
As for learning resources, I came across a decent article on the subject when I was starting out (1), and most of the oscilloscope manufacturers have whitepapers on SMPS diagnostics, the Tektronics one I read a while back (2) gave a good overview. A lot of the whitepapers have a manufacturer-specific focus, but they still have good information that can be applied to almost any oscilloscope.
If you want to get really into the power supply and do high-side measurements you'll need an isolated differential probe, which can cost as much as an inexpensive oscilloscope, but for DC output measurement you shouldn't need anything special. Current probes are a lot more affordable if you're interested in looking at loads or current fluctuations/harmonics, but that's more useful after you've figured out a bit more what specific properties you're trying to measure.
1: https://www.testandmeasurementtips.com/test-switching-power-...
2: https://download.tek.com/document/3GW_23612_7.pdf
Edit: I forgot to mention that the EEVblog forums are a good resource also, but they sometimes aren't as friendly as they could be towards people just starting out.