I wasn't sure if I could mount it to the mill table without it flying off because it was so small, so I mounted it to a ~1cm copper disk with some crystalbond wax.
This will make it much easier to find if I drop it, and give more area for me to attach to the chuck with double-sided tape.
Pretty happy with the results for a surgical decap.
It looks like the quartz crystal sits on top and the oscillator driver is under it. Unfortunately we can't see the oscillator die without destroying the crystal.
Nothing looks obviously damaged, I'll do some higher mag images next.
Composite of three focal planes (upper bond pads/crystal surface, lower bond pads, top of package) on the Labsmore/Mitutoyo system.
The left two pads clearly have connections to the driver IC but aren't very visible with the DOF of this system at the chosen focal planes.
It's interesting that the quartz is a somewhat textured surface, I expected a mirror polish.
Nothing looks obviously broken here. Given the fact that the thing isn't oscillating and the history of ultrasonic cleaning I expected to see the quartz plate come out in multiple fragments (one of the reason I wanted to be so cautious opening it, I didn't want to lose shards of it).
Any ideas on other tests or angles I should do before I try to remove the quartz (likely destroying it in the process) to expose the controller die and see if maybe something is up with the wire bonds?
I don't think I can test electrical connectivity between the quartz and the mounting pads with my current setup, gut feeling is that touching it with any of my existing probe needles would shatter it. Maybe I'll try if I'm going to rip it out or something.
Wire bonds from the controller die to the package, seen through the quartz crystal so pretty blurry.
But they definitely look like second / wedge bonds from gold ball bonding.
Bottom right terminal with focal plane swept from top surface down to the package pad.
No visually evident damage or cracks here.
S21 of the resonator measured at the gold pads on the substrate as best I could. The noise in the left area is me moving the probe into position, I couldn't position the probes and trigger the sweep with only two hands.
Interestingly it seems to resonate at 20 MHz not 10, I guess there's a divide by 2 somewhere in the output stage?
Oh yay, I thought my wife had gone to bed already but she was still up. Got her to click a few buttons for me and now I have a photo of the measurement setup and a clean VNA sweep with a wider bandwidth.
Sure looks like the resonator is intact.
Anyway, that's multiple pieces of evidence to suggest something catastrophic happened to the controller chip and that the resonator itself is fine.
So I guess I'm at the point where I need to rip off the quartz crystal to see what the controller looks like.
@f4grx All of the pins of the package measure open circuit and the output is flatlined.
We're not even reaching the point that it *tries* to oscillate. it's something far more fundamental (pun not intended)
@azonenberg if the unit was sonicated it's possible that invisible internal stresses in the quartz shifted its resonances even if the whole resonator looks undamaged.
Even if the amplifier is the obviously damaged part as you diagnosed, it would be interesting to see the difference in resonator behaviour, for curiosity.
I would be interested if it could be powered up again with the window open and seeing if physical manipulation to the crystal surface would result in amplifier output š¤
@azonenberg There really needs to be a foot pedal (or voice command) to trigger scopes. I never think about it until it's too late.
So now I google it in another window. I need a 1/4" to BNC adaptor for my keyboard pedal.
"External Input (EXT): A simple momentary footswitch can be connected to the "Ext Trig" BNC input on the back of many Tektronix scopes, allowing a foot press to trigger a sweep."
@azonenberg @recursive probably not a pll, that would be overkill. Slight adjustmemts would mean a fractional synth and inevitable spurs.
trimming is usually capacitive and temp sensing is just a diode somewhere in the capacitive feedback. tcxos are deceptively simple sometimes.
whats the part number of the unit? Cant find it in your recent toots.
That's a good microscope!
It better be given how much it cost, lol.
The difference between no name AliExpress optics and good German or Japanese glass is staggering but you get what you pay for.
Wishing I could afford a Leica! But worth it!
@dianea Oh absolutely. We have amscopes at work, they're enough most of the time.
But for professional use in my own lab when I don't need to jump through management to get budgetary approval and can just pull out my credit card? I will absolutely pay what it takes to get good glass.
@azonenberg @dianea the "custom CNC platform" looks exactly like one of those cheap chinese CNC routers. That feels so wrong, the nice japanese optics on a motion stage without real axial bearings on the spindles šµāš«
But I suppose without load (beyond the weight of the optics), and backlash avoidant toolpaths that caaaaan be pretty precise... still feels wrong to me.
@la @dianea The custom bit is the integration, I got the router frame + motion controller + optics assembly as a turnkey solution rather than having to DIY it (which some people do but I didn't want to jump through the hoops).
The motion planner has some backlash compensation but for the most part you don't need ultra tight repeatability for step-and-repeat imaging, you just need enough precision that the stitching software can align one tile to the next. If you're a few microns out of a perfect 30% overlap it's fine.
The main things I care about are good optics, not vibrating, and taking many images per hour without me having to manually move the stage between images. It does that just fine.
@la @dianea honestly if they had gone overboard on the stage axes for this application I would have complained a bit, I want to put my money into glass not metal :P
It's also a huge upgrade from my last stage in smoothness (it had large, visible steps each time you moved, plus the axes would sometimes stick and jerk). This is butter smooth. There is a tiny bit of backlash (noticeable in a system with 300nm depth of focus) in the Z axis if you're doing manual jogging on the focus but not much, and when it's doing plane-fit interpolation it does backlash compensation on the toolpaths.
@azonenberg @dianea Fair enough
I think of automated measuring equipment and images of hundreds of kilos of granite pop into my head, but that's not optical... I am a bit surprised that at those recorded feature sizes the woble in MGN rails and 2020 alu extrusion doesn't wobble too much, but I guess if you wait a moment before taking the picture it's fine š¤·āāļø
@la @dianea Yeah the movement is small (a few tens of Ī¼m from one tile to the next at high magnification, a few hundred at low mag) then it waits a little while for vibration within the system to damp out before snapping the image.
It averages around 2-2.5K photos an hour so a bit under 1 Hz repetition rate, I forget how many ms the settling time after the movement is. There's an adjustment control for it, the factory default worked well with the 20x objective but there was still a little motion blur with the 100 from not being fully damped out so I slowed it down.
The bigger problem I had was actually vibration from the HVAC coupling through the walls/floor and into the table, which made 100x nearly unusable until I got the vibration isolation system to put under it.
I do love the AmAcopes at my work. They are enjoyable to use for an entire shift. Microwave transistors that I can't really see with my eyes are easy to work with those optics š
One day I might get one for the house
@dianea I will say from experience the difference between no microscope and an amscope is much larger than the difference between an amscope and a Leica.
It's like going from no car to a beat up Honda Civic to a Ferrari. Sure, if you can afford the Ferrari it'll be more fun to drive. But the Honda will absolutely get you to work and the grocery store and back for a fraction of the price.
My grandfather owned Leica cameras and had their own color darkroom to promote the family landscaping business. So many amazing memories captured by a Leica šļø
Andrew Zonenberg
F4GRX SĆĀ©bastien
diana š³ļøāā§ļøš¦š±
Ben
recursive š³ļøāš
Aaron Holtzman
Laura