Probing small SMT pieces - Page 1
Forum section: electronics / projects

author: mazurov
author_rank: Frequent Contributor
timestamp: January 19, 2022, 12:59:37 am
content: Looking for ideas on how to probe small SMT pieces on a PCB. Mine is on the pictures. I can probe all right under an optical microscope but then I can't see the oscilloscope screen. Digital has issues (or rather I do) with depth perception and I can't place the probe reliably so I have to turn off the supply, place the probe, turn on the supply, and only then operate the scope, take screenshots, etc. Are there better ways to do it?

author: MathWizard
author_rank: Super Contributor
timestamp: January 19, 2022, 08:11:44 am
content: Any time I'm working on small chips, I pretty don't touch them unless I solder on some little wires 1st. And that's with fairly large pitch chips. I'm sure there's lots of chips I don't even have wire fine enough for their pitch.My hands are not that bad, but I don't trust my self on chips I own, let alone if I was working on some one else gear.

author: julian1
author_rank: Frequent Contributor
timestamp: January 19, 2022, 08:16:40 am
content: I have been really tempted by these

author: TheUnnamedNewbie
author_rank: Super Contributor
timestamp: January 19, 2022, 08:59:37 am
content: I have no idea what they cost second hand, but probe-station XYZ stages could be solution? It's what we use to probe bare silicon dies, so they have very precise control.

author: Haenk
author_rank: Super Contributor
timestamp: January 19, 2022, 09:17:49 am
content: Quick note: Do not use antistatic foil to place your PCB on - it is conductive and will very likely alter your measurements.Other than that, there are not horrible expensive (used) XY-tables for microscopes available, which are also very accurate.You may also want to take a look athttps://sensepeek.com/cheaper would be a "helping hand" (or "3rd hand"), those are usually only a couple of EUR/USD...Edit: Hah. Julian beat me to it. Note to self - don't write a comment while working and submit it much later

author: mazurov
author_rank: Frequent Contributor
timestamp: January 19, 2022, 05:30:31 pm
content: Quote from: TheUnnamedNewbie on January 19, 2022, 08:59:37 amThat's what I meant to ask next :-). I don't have access to one anymore and can't recall the layout. Do you know how they place the probes so that they don't block the view?

author: mazurov
author_rank: Frequent Contributor
timestamp: January 19, 2022, 05:43:47 pm
content: Quote from: Haenk on January 19, 2022, 09:17:49 amMy HP34401A disagrees. In my experience, similar-looking anti-static materials have very different resistance so I always measure. Foil and pink PE are often OK as well as pink foam, bubble wrap etc. while black foam is often too conductive for anything but storage.

author: mazurov
author_rank: Frequent Contributor
timestamp: January 25, 2022, 12:35:47 am
content: PCBite is the ticket. Usable for pitches down to at least 0.35mm, fits perfectly into my setup by directly attaching to the vice base. The included grabber is very shitty for some reason but this is normal for included grabbers.

author: LaryPant
author_rank: Contributor
timestamp: January 25, 2022, 09:39:09 pm
content: Quote from: mazurov on January 19, 2022, 05:30:31 pmAt the university lab were I worked on characterizing nanomaterials they use these XYZ probe stations with very thin needles as probes - they pretty much looked like sewing needles - and they interfaced with the pads at an angle of 45 degrees or thereabout and they did not block the view through the microscope.

author: Kjelt
author_rank: Super Contributor
timestamp: January 25, 2022, 10:14:19 pm
content: Quote from: mazurov on January 25, 2022, 12:35:47 amAgree, friend of mine uses Sensepeek PCBite for over a year and is very happy with it.