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Agilent 2000a / 3000a Oscilloscope NAND Recovery

salvagedcircuitry.com

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Re: Agilent 2000a / 3000a Oscilloscope NAND Recovery

#31

Post by dezgeg »

salvagedcircuit wrote: post #29
userbinator wrote: post #16

That 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.

I assume that's because wear leveling is something that would be implemented purely in software, so there's no much point having such info in a hardware manual.

Re: Agilent 2000a / 3000a Oscilloscope NAND Recovery

#33

Post by james_a_craig »

CamperBob2 wrote: post #17
jjoonathan wrote: post #10

Earlier quoted context omitted.

Oh wow, I was just transplanting some TC702 amplifiers to save the doubler in an old 50GHz HP signal generator... would that have been designed by these guys back when they were part of HP? https://www.keysight.com/us/en/assets/7018-04165/application... EDIT: that's registration-walled, but this HP Journal article isn't. https://archive.org/details/Hewlett-Packard_Journal_Vol._42_... The amplifiers in question are bl…

83650? I've heard those output amps are very unreliable. Been lucky so far with the one in my 8510C rig.

One of the few places you run into fellow 8510C users. How stable do you find your calibration on the 50GHz 83650 setup? My 20GHz one with the 8341B is very, very, very drifty for the first couple of hours after powerup (i.e. a good load goes from -60dB to about -15dB half an hour after calibration), but I'm not sure whether it's normal or something up.

Re: Agilent 2000a / 3000a Oscilloscope NAND Recovery

#34

Post by fuzzfactor »

salvagedcircuit wrote: post #23
cardiffspaceman wrote: post #12

// “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

If you're going to do things that other people don't normally do, you might have to build things that other people don't normally build.

Not only that, while you're at it,

If you're going to build things that other people don't normally build, you might have to do things that other people don't normally do.

And it could never end, so way before it's over you could end up with a lot of capabilities other people don't normally have.

Plus when you end up like that, of course it's not over, it's just getting started ;)

Re: Agilent 2000a / 3000a Oscilloscope NAND Recovery

#35

Post by salvagedcircuit »

fuzzfactor wrote: post #34
salvagedcircuit wrote: post #23

Earlier quoted context omitted.

Thanks! It was well worth it :D

If you're going to do things that other people don't normally do, you might have to build things that other people don't normally build. Not only that, while you're at it, If you're going to build things that other people don't normally build, you might have to do things that other people don't normally do. And it could never end, so way before it's over you could end up with a lot of capabilities other people don't…

There's always more to discover! Thanks for the kind words.

Re: Agilent 2000a / 3000a Oscilloscope NAND Recovery

#36

Post by CamperBob2 »

james_a_craig wrote: post #33
CamperBob2 wrote: post #17

Earlier quoted context omitted.

83650? I've heard those output amps are very unreliable. Been lucky so far with the one in my 8510C rig.

One of the few places you run into fellow 8510C users. How stable do you find your calibration on the 50GHz 83650 setup? My 20GHz one with the 8341B is very, very, very drifty for the first couple of hours after powerup (i.e. a good load goes from -60dB to about -15dB half an hour after calibration), but I'm not sure whether it's normal or something up.

That doesn't sound right at all. I mostly use mine as a TDR (50 GHz with 83651B) but I can generally reload saved calibrations from months ago, less than 5 minutes after a cold start, and still see I'd go through the receiver channel tests in the manual and try to isolate the problem to the test set or IF box. Does S21 drift as well?

Re: Agilent 2000a / 3000a Oscilloscope NAND Recovery

#37

Post by jjoonathan »

CamperBob2 wrote: post #36
james_a_craig wrote: post #33

Earlier quoted context omitted.

One of the few places you run into fellow 8510C users. How stable do you find your calibration on the 50GHz 83650 setup? My 20GHz one with the 8341B is very, very, very drifty for the first couple of hours after powerup (i.e. a good load goes from -60dB to about -15dB half an hour after calibration), but I'm not sure whether it's normal or something up.

That doesn't sound right at all. I mostly use mine as a TDR (50 GHz with 83651B) but I can generally reload saved calibrations from months ago, less than 5 minutes after a cold start, and still see I'd go through the receiver channel tests in the manual and try to isolate the problem to the test set or IF box. Does S21 drift as well?

Yes, I'd expect better (though maybe not necessarily 50dB+). Troubleshooting:

1. First suspect is always a bad calibration -- they tend to be unstable in addition to incorrect, but if you have anything with known(-ish) S parameters you can check for correctness too.

2. Second step is to put it in TDR mode and watch to see where the TDR changes. That's where your problem is.

3. A trip through the test set with a torque wrench is a good way to not just check the connections but also calibrate your intuition about the couplers/mixers, which should help interpret #2. You can loosen connectors in sequence and watch them spike on TDR to zero in on the actual problem.

As it happens, I was comparing my 8510C + 8517B to a FieldFox recently and I took some drift measurements, although those were on a short rather than a load. The 8510C blew the FieldFox out of the water, lol. Given the TDR, this might be because the standard itself was temperature sensitive and the FieldFox ports are piping hot, but still.

https://jjoonathan.github.io/plot_drift.html

In case they are useful, here are a bunch of different standards measured by the two instruments.

https://github.com/jjoonathan/cal-std-8510-fieldfox/blob/mai...

EDIT: Also worth mentioning, I recently upstreamed my nice 8510C driver into scikit-rf!

https://scikit-rf.readthedocs.io/en/latest/api/vi/generated/...

Re: Agilent 2000a / 3000a Oscilloscope NAND Recovery

#38

Post by jjoonathan »

CamperBob2 wrote: post #17
jjoonathan wrote: post #10

Earlier quoted context omitted.

Oh wow, I was just transplanting some TC702 amplifiers to save the doubler in an old 50GHz HP signal generator... would that have been designed by these guys back when they were part of HP? https://www.keysight.com/us/en/assets/7018-04165/application... EDIT: that's registration-walled, but this HP Journal article isn't. https://archive.org/details/Hewlett-Packard_Journal_Vol._42_... The amplifiers in question are bl…

83650? I've heard those output amps are very unreliable. Been lucky so far with the one in my 8510C rig.

They've treated me fine -- the broken one I bought that way. YTOs have given me trouble, though.

EDIT: obligatory, pictures https://photos.app.goo.gl/KwvnMGm5GyvnmgE58

Re: Agilent 2000a / 3000a Oscilloscope NAND Recovery

#39

Post by james_a_craig »

CamperBob2 wrote: post #36
james_a_craig wrote: post #33

Earlier quoted context omitted.

One of the few places you run into fellow 8510C users. How stable do you find your calibration on the 50GHz 83650 setup? My 20GHz one with the 8341B is very, very, very drifty for the first couple of hours after powerup (i.e. a good load goes from -60dB to about -15dB half an hour after calibration), but I'm not sure whether it's normal or something up.

That doesn't sound right at all. I mostly use mine as a TDR (50 GHz with 83651B) but I can generally reload saved calibrations from months ago, less than 5 minutes after a cold start, and still see I'd go through the receiver channel tests in the manual and try to isolate the problem to the test set or IF box. Does S21 drift as well?

Thanks, it's really useful to have a reference point. Having played about a bit with which device is left to warm up, I'm fairly sure it's the 85102 (IF box) that's drifting. I've also tried my old 8350B sweeper instead of the 8341B and although the pattern's very different (different band-switch points) it drifts about equally badly. The odd bit is that it looks like it's related to the sweep position - I get a sawtooth effect as it drifts, like so: https://www.jamiecraig.com/wp-content/uploads/2024/06/image....

Re: Agilent 2000a / 3000a Oscilloscope NAND Recovery

#40

Post by james_a_craig »

jjoonathan wrote: post #37
CamperBob2 wrote: post #36

Earlier quoted context omitted.

That doesn't sound right at all. I mostly use mine as a TDR (50 GHz with 83651B) but I can generally reload saved calibrations from months ago, less than 5 minutes after a cold start, and still see I'd go through the receiver channel tests in the manual and try to isolate the problem to the test set or IF box. Does S21 drift as well?

Yes, I'd expect better (though maybe not necessarily 50dB+). Troubleshooting: 1. First suspect is always a bad calibration -- they tend to be unstable in addition to incorrect, but if you have anything with known(-ish) S parameters you can check for correctness too. 2. Second step is to put it in TDR mode and watch to see where the TDR changes. That's where your problem is. 3. A trip through the test set with a torqu…

Thanks for the suggestions - I'll definitely have a poke at it in TDR mode, that's a good plan.

Thanks also for the scikit-rf driver - I've an 8753ES as well, and I've used scikit-rf with that, but not yet with the 8510.

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