I got lucky - the "broken, unknown state" oscilloscope I got off eBay that cost US $80,000 new only needed a $16 part replaced.
Feast your eyes on some pretty awesome screenshots. to the first person who knows and can explain the physics behind the first 2 pictures.
@wohali Nice find!
I'm gonna guess that filters are involved. The first looks like you're looking at a signal that's passing through a multi-stage filter. Not sure about the second one.
Nope, no filters. The same signal is going to each input of the scope. Look at both 1 and 2 - the change is highlighted on the 2nd screen - and it might become clearer.
@wohali Hmm... you're adding those two humps together to get a bigger spikier hump?
@not_on_pizza you're on the right track...another hint: nothing changed in the _physical_ setup between the two screenshots.
spoilers Show more
In the first you can see the built-in pulse generator connected to each of the 4 inputs in turn. They don't all happen at the same time, because of the slight delay introduced by the cable length between each input.
In the second screenshot I turned off the termination on the 4th channel and grounded the input, so you can see the pulse actually reflect off the input and back up to channels 3, 2 and 1.
How's that for a demonstration of physics? :)
@wohali wow this looks much nicer than the (apparently better and newer) xp based lecroy we have at work
@MightyPork thanks! this was the ~last generation of VxWorks based scopes. ~96MHz PowerPC 603e. It's a joy to use so far.
@wohali ohhh they used VxWorks?? This is such a step backwards 🤦♂️
@MightyPork wait! i was wrong. mine is actually a proprietary OS. the next 2 revisions ran on VxWorks, then they switched to the Windows XP/7 embedded PCs they use now.
@wohali how responsive is it? The xp one likes to randomly pause and think things over and crap like that, as you'd expect on old widows
@wohali (thanks autocorrect lol)
@MightyPork Haha, after changing specific settings it'll click a couple of relays and pause for ~1-1.5s or so. The user group jokingly calls this the "Walter LeCroy Memorial Second" :D
It's pretty good as long as you aren't crossing one of those boundaries.
FYI the story of them moving from the original custom OS to VxWorks (before moving to Windows): https://www.researchgate.net/publication/220220764_Re-engineering_at_LeCroy_Corporation_The_move_to_component-based_systems
@wohali I don't know what any of these are but I kinda want to embroider them
@wohali how much did it cost you offuv ebay? (I, have no idea what it all means but would love to find out :)
@Zoonie about $500 US. Spending that much on a new scope gets you about 10% of the bandwidth and 25% of the sample rate.
@wohali fantastic! It is ridiculous how few people know how to mend electronic products these days. Which makes for a good bargain :)
@Zoonie i like your avatar!
@wohali that's a nice thing to say, thank you! It's been my online icon since about 1997. I drew it along with a bunch of other icons for an 'online diary', hand-built in html 1.01! Heh.
@Zoonie <3 here's the one of me that I drew about 15 years ago, I use it many places.
@wohali ha ha! Fantastic. Hand drawn is So much better than just some gif or other