<d1b2>
<azonenberg> The nickel leadwire has a "nail head" formed into the end of it, then it's soldered to what appears to be a relatively standard 0402 sized chip resistor and inserted into the fiber-reinforced plastic cup
<d1b2>
<azonenberg> then potted with the overmolding compound
<d1b2>
<azonenberg> but as you can see here the potting is completely missing on the upper side of the solder joint, thus providing no reinforcement for it
<azonenberg>
Anyway, I shared this data with Vishay who is doing their own investigation as well
<azonenberg>
So we'll see what they come up with
<d1b2>
<Darius> nice
<d1b2>
<Darius> I mean not nice for you, but cool shots 🙂
<azonenberg>
I'm being nice to Vishay and not tweeting these, but figured i'd share with the channel so people know status of things
<azonenberg>
anyway, back to refactoring for a while
<electronic_eel>
nice shots
<electronic_eel>
shouldn't the nail thing also sit a little more centered? that should give a more even cavity for the molding
<azonenberg>
Yes, there is also inconsistency in placement of the lead WRT the terminal of the resistor
<azonenberg>
That may be a contributing factor but in these photos, the nail head is very close to the bottom side
<azonenberg>
but the solder fillet is still pretty uniform
<azonenberg>
so the cavity dimensions are about what they should be
<azonenberg>
the concerning bit is that the top right is a big void, and at the bottom right you can see the potting is detached from the lead wire
<azonenberg>
thus providing no real support on either side
<azonenberg>
but at least at the bottom it's still reinforcing the solder joint
<azonenberg>
at top, it's not
<electronic_eel>
yeah, sure, the potting is the main problem
<azonenberg>
There's a few air bubbles and such in the potting but i'm not really worried about those (although some of those bubbles are quite large)
<azonenberg>
i also have seen what looks like the potting detaching from the plastic in spots. I want to probably section one of those as well, and see if the whole resistor+potting is maybe sliding out of the plastic cup a bit
<electronic_eel>
i think they have to retune the process for these. maybe the machine doing them didn' t run for 5 years and needs some oiling and readjustment
<azonenberg>
see there, it looks like the entire contents of the white plastic cup detached and moved right relative to the cup
<azonenberg>
And yes, it seems like they have process issues. maybe the black goop is something they bought in 2017 last time lecroy or keysight ordered a thousand of them
<electronic_eel>
yeah, there is like a crack
<azonenberg>
and it's started to congeal or something and not flow right
<azonenberg>
could be lots of things
<azonenberg>
and no, it's not a crack
<azonenberg>
look closely at the bottom side
<azonenberg>
you can see a nice square extrusion
<azonenberg>
it looks like an exact negative of the plastic cup
<azonenberg>
seems like poor adhesion between the cup and the potting and they're starting to separate
<d1b2>
<azonenberg> This is one of the ones I sent them for FA. the one i sectioned looks similar though
<d1b2>
<azonenberg> you can see lead through the gap at ecnter
<azonenberg>
Anyway, yeah this level of inconsistency is not what i would expect from a well optimized manfuacturing process
<azonenberg>
but like i said, it's good that they're not telling me to get lost
<electronic_eel>
oh yeah. many other mfgs wouldn't really care about this
<azonenberg>
yeah quite the opposite, i'm on an email thread with my sales manager, my local vishay rep, and five other engineers/technicians from around vishay responsible for QA and production
<azonenberg>
several of which appear to be based out of the factory in Mexico that actually makes these
<azonenberg>
Vishay has a reputation for quality and when they get things wrong, it seems they're willing to go the extra mile to make it right
<azonenberg>
The fact that these same resistors are (almost certainly) used by every other big T&M vendor for their probes probably has something to do with it
<azonenberg>
I may have been the one who got unlucky and had a bad batch, but imagine how they'd have responded if keysight or lecroy contacted them about the same problem
<azonenberg>
i think they're very concerned about the potential for that to happen and want to get ahead of the issue before it affects a higher volume customer
<azonenberg>
I also told them we have a production order of our own that is gated on a satisfactory resolution to the process issues
<azonenberg>
matt was all ready to put in a volume purchase of the HMLs for the AKL-PT5 production run when i told him i had noticed some weirdness
<azonenberg>
and we put the order on hold
<azonenberg>
Anyway, i expect it will be a while before we hear very much from them. the box I sent them with the components for FA was only picked up by fedex today
<electronic_eel>
my guess is that scheduling a new production run is the thing that will take them longest
<azonenberg>
Well yes, when we actually put in the order it will probably be a multi month lead time like the last one
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<azonenberg>
The good news is that i've been screening them visually
<azonenberg>
and i have plenty for prototyping and likely even PVT
<azonenberg>
at least of the PT5. the AD4 uses twice as many of them so we might run short there for a reasonable sized PVT run
<azonenberg>
and then the AV1 uses the 100 ohms, the lot i have of those appears to be better
<azonenberg>
there are some sketchy looking bits of overmold but overall not nearly as much voiding and degradation like this
<azonenberg>
then the PR1 will use either nothing or 100, i'm testing both configurations and still experimenting to see what will work best
<azonenberg>
So i don't think the issue will be gating R&D any time soon
<azonenberg>
Also, the diff for the waveform refactor is up to 3800 lines and i'm up to files beginning with M in libscopehal
<azonenberg>
(scopeprotocols is still untouched)
<azonenberg>
Several more days at this rate
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<miek>
azonenberg: with those fancy rosenberger connectors, do they work purely on compression or does the pin still need to be soldered?
<azonenberg>
The 32K243-40ML5? I generally solder the center pin and rely on compression for the ground
<azonenberg>
that gives excellent performance but is still fairly easy to take off should i want to recycle the connector
<miek>
thanks!
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<d1b2>
<azonenberg> Comparison - i posted this some time ago, this is from March
<d1b2>
<azonenberg> one of the 100 ohm HML engineering samples I was sent in January
<d1b2>
<azonenberg> sectioned 90 degrees perpendicular to the one i did last night
<d1b2>
<azonenberg> (this is looking into the side of the embedded 0402, while yesterday's pics were coming from the top or bottom)
<d1b2>
<azonenberg> note that while there is a large void deep inside the plastic cup, the opening of the cup has a solid, uniform filling
<d1b2>
<azonenberg> the potting is solidly adhered to the cup and the lead (not peeling away) and is adequately reinforcing the leads
<azonenberg>
i went through the pile and i found a couple more that looked sketchy. I'm wondering if it might be instructive to try and replicate the original failure mode
<azonenberg>
put it on a PT5, sonicate it, and see if the lead falls off
<azonenberg>
i need to build another pt5 with the new minicircuits filter anyway
<azonenberg>
So i can just document the hell out of this one and deliberately pick a weak looking resistor, knowing there is a good chance it will fail and need replacement
<d1b2>
<xabean> beautiful pictures btw!
<d1b2>
<xabean> I'm assuming these cross sections are all potted again in epoxy, then sanded down to the region you want to inspect?
<azonenberg>
Correct. They;re put in a circular silicone mold and cast into a block of clear resin, in this case AA-Bond F113 from Atom Adhesives
<d1b2>
<johnsel> you could use a better mic though lol
<azonenberg>
I've gone through several iterations. But the mic isn't the main issue
<azonenberg>
the issue is that the ambient noise in the lab is quite loud, around 65 dBA, from the 24/7 HVAC plus all of the cooling fans from various equipment
<azonenberg>
i have to do fairly extensive DSP to remove it from recordings
<azonenberg>
and that does make voices sound less good
<azonenberg>
ideally i'd get like a noise canceling aircraft mic or something
<d1b2>
<johnsel> a proper lapel mic can pick up only the voice sound
<d1b2>
<johnsel> they solve this exact issue
<azonenberg>
yeah if anyone has suggestions on something (exact products i mean) let me know, it's one of my known weak points
<azonenberg>
i just know most things i've tried still picked up the ambient noise
<azonenberg>
i tried a wireless mic a while back and there was horrific background chirping noises
<azonenberg>
not sure if EMI from my lab or the mic was that bad
<azonenberg>
here's an unedited raw version of one take from that video (not one i ultimately used in the final cut, but that's irrelevant)
<azonenberg>
just so you can hear the ambient noise level
<d1b2>
<johnsel> I am actually walking back my recommendation, you might be better of with a more directional mic
<azonenberg>
Directional may not be enough because the sound is all over the lab and you'll just zero in on bounce from the wall behind me
<azonenberg>
i think it has to be an active a-minus-b type cancellation filter
<azonenberg>
that has an omni and a directional and only records the delta
<azonenberg>
or something to that effect
<azonenberg>
i dont know exactly how they work but if people can use them in helicopters and understand each other, they should handle my ambient noise just fine
<d1b2>
<johnsel> no, you just need to point it to your mouth
<azonenberg>
Anyway, whatever it is, i need to figure out exactly what to get and ideally some way of getting the signal to a PC mic port without excessive noise or dragging cables around the lab while i move
<d1b2>
<johnsel> though that is xlr and balanced and actively powered
<d1b2>
<johnsel> not something you can put in a 3.5mm plug
<d1b2>
<johnsel> but it is the type of mic that is most appropriate, they're also used to record say a single instrument in an orchestra
<azonenberg>
Yeah. but like i said i'm not an a/v professional who knows about this stuff
<d1b2>
<johnsel> you could go your approach but those microphones definitely don't have audio quality as a requirement
<azonenberg>
if someone can suggest a reasonably priced pipeline that goes from X to a 3.5mm input
<azonenberg>
i'm all for it
<azonenberg>
i just dont have the time to do the research and pick out all the necessary components and adapters
<d1b2>
<xabean> buy a cheap two channel mixer board off amazon that has XLR and RCA or TRS outputs?
<d1b2>
<johnsel> did you use a mobo built in sound card?
<azonenberg>
i've tried that and a usb sound card
<d1b2>
<xabean> that's what I did, but I also had a cheap mic, and I'm not sure what if any phantom power the mixer board I had could provide
<azonenberg>
no discernable difference in performance, the mic/noise were the limiting factors
<azonenberg>
anyway... requirements are that the final output is 3.5mm into a PC sound card, and that there be no cables on the floor dragging behind me i can trip on
<azonenberg>
you can have whatever you want on the rx side going into the pc, and i can handle some kind of portable box on my belt/pocket/whatever to transmit
<d1b2>
<johnsel> sure sure but the average pc motherboard has horrible sound quality too, so you might only move the problem
<d1b2>
<johnsel> or have bought something already
<azonenberg>
ok fine. final output is 3.5mm or usb
<azonenberg>
(and is a standard usb audio class not something proprietary that needs a windows driver etc)
<monochroma>
the specific term i am familiar with for recording quality PC audio inputs is "Audio Interface"
<d1b2>
<johnsel> and ofcourse you are an expert in this azonenberg, just pretend it's not hz but ghz and it's not a microphone but an antenna
<d1b2>
<johnsel> hmm the manufacturers I know either don't offer it or don't offer it in connectivity options that would be suitable. So other than what I already said about which type of mic would be suitable I can't help