https://reddit.com/r/AskElectronics/comments/qxpfxl/how_to_attach_logic_probes_to_tiny_smd_components/

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jmpz11
 

How to attach logic probes to tiny smd components

I have a very small circuit board lacking any test points that I need
to probe - in a bunch of places simultaneously. I know this isn't a
new thing to need to do, and there must be a better way.

There are smd components and smd connectors with leads closer
together than any (insulated) wires I have available (see image). My
soldering iron tip is wider than the connector leads are apart (and
I've never seen a soldering iron with a pinpoint tip, nor have I had
much luck melting solder with the very tip...)

How the heck do you solder on to something to tiny?? Where do you get
the right kind of wires (insulated, VERY thin, very flexible)?

 Didn't go well...

I tried with a soldering iron and managed to tear a component along
with the circuit board pad off the board :(.

I then tried again with some thinner wires, solder paste and a
hot-air rework station. I thought it went ok till I took a picture
and discovered only one wire connected correctly... and I bridged a
bunch of parts!

I have a replacement board on the way (torn-off pad doesn't appear to
have any surface traces to "resurrect"), but I still need to probe
the heck out of it. There is a 10-pin connector with lead spacing too
small for even my needle probe (and butter-claws) that I will be
needing to probe and I don't have a clue how I'm going to do that.

Please tell me there are some tools / methods / things to facilitate
such diagnostics...

(If I knew the spec for that connector I could maybe get / build a
MITM breakout board - and I may end up needing that eventually, but I
still need to be able to probe the other parts)

Any help is greatly appreciated!

EDIT: Thanks for all the tips. Here are my conclusions for reference:

 1. Use a temperature controlled soldering iron with a ceramic core
    heating element. They are cheaper on Amazon than the crusty
    hardware-store irons, and they make tips just for this purpose.
    (I did not realize how crusty my Weller station was, or how cheap
    a decent one can be had)

 2. Use 30 AWG "wire wrap" aka "Kynar" or varnished (speaker / coil)
    wire. My wires are WAY too big.

 3. Flux liberally, pre-apply solder to wire and connecting surface
    (use solder blob on tip to add solder to the component) then
    "tack" them together quickly with the iron

 4. Use magnification and ample lighting

 5. Alternatively, 3d print a jig and use acupuncture needles: https:
    //hackaday.com/2019/11/15/
    needling-your-projects-3d-printed-pcb-probing-jig-uses-accupuncture-needles
    /

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