I love seeing ridiculously technical investigations like this. It has zero relevance to me but it’s just sooo satisfying to see someone solve a tough problem.
Thanks! I'm glad you enjoyed it :D
Agilent 2000a / 3000a Oscilloscope NAND Recovery
21–30 of 42 posts
Re: Agilent 2000a / 3000a Oscilloscope NAND Recovery
#22This is an awesome write up! I have one of these scopes, with exactly this issue after a long period in storage. When I was looking into it a few years ago the failure mode was known but I couldn't find a recovery procedure. I'll need to give this a try when I get a few hours. I have been putting off getting a new scope in hopes that I could repair this issue.
Thanks! Go for it or contact Keysight to see if they will cover it. Good luck!
Re: Agilent 2000a / 3000a Oscilloscope NAND Recovery
#23// “You will need an oscilloscope, passive probes, …” That’s my stop. This engineer is determined! Built a test circuit to identify one part.
Thanks! It was well worth it :D
Re: Agilent 2000a / 3000a Oscilloscope NAND Recovery
#24This guy knows his oscilloscopes.
Thanks!
Re: Agilent 2000a / 3000a Oscilloscope NAND Recovery
#25It's so good and satisfying to see a person ply a trade to success. When I find myself stressed out for some reason, I like to do something I'm well trained at to help my brain kind of reset, which often gives me a different way of looking at what stressed me in the first place.
Absolutely! I find repair to be therapeutic at times, like repairing a stuck or dirty 1970s film camera lens. It's usually a straight forward repair, it just takes a bunch of patience and attention to detail. This repair was far more complicated than that, but it was worthwhile to get another instrument working around the lab.
Re: Agilent 2000a / 3000a Oscilloscope NAND Recovery
#26This is an excellent writeup, it's refreshing to see detailed writeups that are quick to load
Thanks. I like to keep things lightweight :D
Re: Agilent 2000a / 3000a Oscilloscope NAND Recovery
#27If you like this kind of content, I highly recommend checking out the Youtube channel 'The Signal Path' [1]. It has some fantastic technical teardowns and repairs of instruments, including really high frequency equipment. [1] https://www.youtube.com/channel/UCKxRARSpahF1Mt-2vbPug-g
Woah, thanks for the comparison. I'm a huge fan of the signal path and marco reps, but I don't think I've gone that far down the volt nut path yet. Maybe I need to fix up a broken 3458a for my next writeup :D
Re: Agilent 2000a / 3000a Oscilloscope NAND Recovery
#28This is very interesting. I just have one minor nitpick. Broadcom did not buy Avago, Avago bought Broadcom. They then changed their name to broadcom as it was more recognizable in the industry (while keeping their old stock ticker AVGO as that was more recognizable in the financial industry). This is entirely a tangent but the rise of Avago from a minor second rate spin off from a spinoff from HP to one of the bigges…
Thanks! You sir are correct. I must have been rambling too much on a side tangent. I'll fix this shortly. Optical encoders are most excellent.
Re: Agilent 2000a / 3000a Oscilloscope NAND Recovery
#29That NAND flash is a 128MB SLC part rated for 10 years of retention after 100K cycles. It's interesting that the datasheet says ECC is only "strongly recommended" and not "mandatory", but I guess SLC of the time, unlike MLC and later generations of flash where correctable errors are part of normal operation, was reliable enough that some applications didn't bother using ECC at all. It also recommends the 22-bit/256-b…
Thanks for the input! That is a pretty reasonable conclusion. I was surprised there was no mention of wear leveling or garbage collection in any of the spear documentation when that's essentially assumed today. Wild.
Re: Agilent 2000a / 3000a Oscilloscope NAND Recovery
#30That NAND flash is a 128MB SLC part rated for 10 years of retention after 100K cycles. It's interesting that the datasheet says ECC is only "strongly recommended" and not "mandatory", but I guess SLC of the time, unlike MLC and later generations of flash where correctable errors are part of normal operation, was reliable enough that some applications didn't bother using ECC at all. It also recommends the 22-bit/256-b…
> Flash memory bits wear out after 100,000 to 1,000,000 writes.
I'd think that applies to (low density) NOR flash memory, not (high density) NAND based ones.