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Probing deep and/or narrow into a given unit for troubleshooting

 

Hi all,
I was wondering of asking for thoughts and ideas on probing deep into some units, or maybe just through a narrow clearance. What I'm thinking of is primarily for use with a DMM (vanilla troubleshooting), though maybe scope probes and others could be considered. But the latter is not my priority.?
?
I have a variety of probes, from "witches hats," to "spring hooks" to many others I don't really even know how to call. I got a bunch and I'll never get tired to look for more and diverse ones. I absolutely think there's never enough tools for probing at a bench. My "silver bullet" is this: , but even this is far too large for some low clearance situations. But its length allows me to reach depths nothing else I have here comes close. Everything else is up to about 3" reach.?
?
Sometimes it comes down to having extender cards, or made ejecting a card, attaching (including soldering) a wire and then probing it once the card is back in there. But that's not always possible. Especially with microwave or mm modules, I am weary of disturbing them too much, and there's always more mechanical aspects to messing with them.?
?
What are some creative and crafty solutions others have found useful? Maybe some miraculous tools you've found??
?
Thank you,
Radu.?
 

I have done the tack-wires-on method many times too. A few nodes is easy to handle, with leads held safely with tape to keep from shorting. When there are lots, I usually use some kind of connector like a square pin header or plug at the ends to keep them all together and safer and organized. Then probe each with a test lead including a pin or socket that can stay connected if needed.
?
I happen to have in my pile of test leads the longest grabber hook I've ever seen, and I'd think even longer might be available. I got it decades ago along with other junk, and never knew who made it until just looking now. This one is around five inches from the finger hold to tip, labelled "maxi grabber." I looked up that name, and it seems to be a Pomona product - you'll see all sorts of hits with that. I think this is their model 4225-2, where the "2" is probably the code for red.
?
I've actually seldom used it except on bigger old-school circuitry. Even with longer reach, there are still the problems of manipulation to grab something, and visibility, so you'd still likely have to tack on some kind of node extensions to probe say in a card cage. It's also kind of fat, but good and strong - maybe there are skinnier, lower profile types too.
?
Ed
 

Depends on what the design is:

If I design it, I put in test points or small (0.05 inch) headers for logic analyzers (ditto for the cheapie clones).? Some boards have 0.1 inch headers that go to HP logic pods.

Sometimes a single pin or a hook terminal works.

I have breakout boards for projects that stack boards.? Those have logic analyzer breakouts.

For someone else's designs, you have dip clips of all varieties (go to hamfests, perhaps?), breakout boards as extenders that have lots of test points.? You have standard grabber hooks and sometimes the micrograbbers.? Grabbers and micrograbbers are rather fragile, though.

Self designed generic breakout boards can work with ribbon cables.

Harvey

On 9/19/2024 5:34 PM, Radu Bogdan Dicher wrote:
Hi all,
I was wondering of asking for thoughts and ideas on probing deep into some units, or maybe just through a narrow clearance. What I'm thinking of is primarily for use with a DMM (vanilla troubleshooting), though maybe scope probes and others could be considered. But the latter is not my priority.
I have a variety of probes, from "witches hats," to "spring hooks" to many others I don't really even know how to call. I got a bunch and I'll never get tired to look for more and diverse ones. I absolutely think there's never enough tools for probing at a bench. My "silver bullet" is this: , but even this is far too large for some low clearance situations. But its length allows me to reach depths nothing else I have here comes close. Everything else is up to about 3" reach.
Sometimes it comes down to having extender cards, or made ejecting a card, attaching (including soldering) a wire and then probing it once the card is back in there. But that's not always possible. Especially with microwave or mm modules, I am weary of disturbing them too much, and there's always more mechanical aspects to messing with them.
What are some creative and crafty solutions others have found useful? Maybe some miraculous tools you've found?
Thank you,
Radu.
 

¿ªÔÆÌåÓý

On 2024-09-19 23:34, Radu Bogdan Dicher wrote:
Hi all,
I was wondering of asking for thoughts and ideas on probing deep into some units, or maybe just through a narrow clearance. What I'm thinking of is primarily for use with a DMM (vanilla troubleshooting), though maybe scope probes and others could be considered. But the latter is not my priority.?
?
I have a variety of probes, from "witches hats," to "spring hooks" to many others I don't really even know how to call. I got a bunch and I'll never get tired to look for more and diverse ones. I absolutely think there's never enough tools for probing at a bench. My "silver bullet" is this: , but even this is far too large for some low clearance situations. But its length allows me to reach depths nothing else I have here comes close. Everything else is up to about 3" reach.?
?
Sometimes it comes down to having extender cards, or made ejecting a card, attaching (including soldering) a wire and then probing it once the card is back in there. But that's not always possible. Especially with microwave or mm modules, I am weary of disturbing them too much, and there's always more mechanical aspects to messing with them.?
?
What are some creative and crafty solutions others have found useful? Maybe some miraculous tools you've found??
?
Thank you,
Radu.?


I had a NAND flash overwrite problem in one of my designs some 10 years ago. Mostly BGA chips, so lots of via's.
A connection was needed to the TEK logic analyzer cables.
See the solution below. Wire is transformer wire, isolation melts at the soldering iron tip.
The bottom row (GND pins) was soldered to the GND plane.
After a few days of waiting for the bad write it was found to be a pointer problem caused by a 3rd party library.

Arie

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