# What tools can hold test probes while troubleshooting?

Discussion in 'General Electronics Chat' started by Merlysys, Dec 10, 2013.

1. ### Merlysys Thread Starter New Member

Nov 17, 2013
23
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When troubleshooting a PCB one or both hands will be used to hold the scope or meter or other test probes, making it difficult to adjust the test equipment. With modern PCBs being so densely packed its easy for the hand with the probe to slid off the target.

I know most of your are such experts at this that such a tool is unnecessary , but for the rest of you...what tools are there that will hold our probes freeing our hands to do other tasks? Such a tool should push down with the probe so good contact is made with the PCB's trace/shoe.

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Feb 13, 2012
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3. ### Merlysys Thread Starter New Member

Nov 17, 2013
23
1
NO I am seeking probes for testing points that don't have anything to grab onto. Pls see pic in my original post.

4. ### inwo Well-Known Member

Nov 7, 2013
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315
I spot solder a lead on + and - , then use one probe only.
I know this doesn't work for some tests.

I've slipped too many times trying to hold two probes.

5. ### strantor AAC Fanatic!

Oct 3, 2010
4,295
1,983
I know what you mean, what a PITA! I have a thought of using one of these helping hands to hold the probes, but what a nightmare! you move one, and the other moves. And the movements are too coarse. I thought, if they made test probes with spring loaded points, it would make the helping hands more feasible, but I cannot find spring loaded leads/probes.

6. ### studiot AAC Fanatic!

Nov 9, 2007
5,005
513
I keep a set of croc clip leads and often clip one onto each meter lead point and then at lest one will usually attach somewhere on the circuit board.

Soldering a short temporary wire to the attachment point is another alternative.

A short length of solid copper (not aluminium) wire from telephone or ethernet cable is good for this.

It ia always important to make good connections as poor ones can lead (ha ha) to very misleading (haha again) readings.

7. ### #12 Expert

Nov 30, 2010
16,031
6,542
You have simply described a universal problem, and it isn't going to get better. Computer aided designs are packing everything smaller and smaller. Component level troubleshooters (like me) are becoming useless and extinct. Replacing the whole board is quicker and more profitable, which is supposed to be an excuse for charging \$300 when you could have fixed it for \$10 if the #\$%^&* board would hold still.

absf likes this.
8. ### Metalmann Active Member

Dec 8, 2012
700
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"Component level troubleshooters (like me) are becoming useless and extinct."

#12, I used to think that about us manual Machinists when CNCs arrived on the scene, until an old Tool and Die guy told me......"There will always be a place for all us Manual Machinists, because who'll be there to repair the CNCs?"

He was correct, I've repaired a "whole jar full" of CNCs.

shortbus and absf like this.
9. ### #12 Expert

Nov 30, 2010
16,031
6,542
and I've replaced dozens, if not hundreds of, "black boxes" and circuit boards that I would have repaired in the 1970's.

10. ### ramancini8 Member

Jul 18, 2012
438
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You can make a comfortable living repairing circuits and reselling the boards to installation techs. A new washer motor is \$900, and I just repaired one at a cost of \$1.50 for a thermistor. Sold the repaired motor for \$300, the tech makes \$300, and the next owner saves \$300. Not a bad deal. Just need to make contact with the techs, and one job is enough to spread the word.

11. ### Metalmann Active Member

Dec 8, 2012
700
223
"A new washer motor is \$900,.."

You mean a new washing machine motor?

Totally outrageous.

12. ### ErnieM AAC Fanatic!

Apr 24, 2011
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1,572
Test probes: what is the quantity of test points? any and every or something fixed?

For fixed tests I've always used pogo pins and a bed of nails. For more random testing there are some adjustable probe points out there but they ain't cheap and I can't think of any terms to goggle).

13. ### THE_RB AAC Fanatic!

Feb 11, 2008
5,435
1,305
In the repair industry when taking measurements especially if needing hands free it is common to solder a few little bits of wire to critical solder joints on the PCB, then just use hook clip leads.

Most appliance PCBs have test clip points for gnd and many points like PSU rails and main signal points.

14. ### davebee Well-Known Member

Oct 22, 2008
539
46
When I need to manually probe a difficult-to-contact area, I sometimes grab a sharp sewing needle in an alligator clip and press the needle point into the metallic junction just hard enough to grip. That way, the needle won't slip off as I look away to check the meter reading. This works great even with the tiniest surface mount parts.

I've only ever done that while holding the alligator clip in my hands, but I'd imagine something like that would also work if some kind of mechanical linkage were to hold it down with a firm enough pressure.

15. ### studiot AAC Fanatic!

Nov 9, 2007
5,005
513
My experience with croc clips plus pins and needles is that some work better than others, it depends upon the alloy. Some are suprisingly high resistance.

So use this method, but make sure that you probe works reliable on a known surface first.

16. ### alfacliff Well-Known Member

Dec 13, 2013
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a possible solution is to tape a pair of probes to a pair of chopsticks, a little practice helps, also a hole drilled into your bench to hold one probe helps if one point is on the bottom of the board.

17. ### alfacliff Well-Known Member

Dec 13, 2013
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rhe biggest problem for me is that most companies dont supply diagrams or part lists for their products any more. one switching supply I was working on I got the origional manufacturer by email, hey said its propriatry, and they couldnt let me have the diagram. then a week later they sent me the diagram with a note that they hadnt sold one for 10 years, so they didnt really have to protect them as much.
experience helps, I have worked on stuff from the tube days to surface mount, and can usualy figure out the problem. By the way, 85% of bad newer stuff is electrolytic caps spitting on the board.
cliff

18. ### matty204359 Member

Apr 6, 2011
105
3
we leared in circuits 101 that you clip one lead on ground and only probe with the other. If you need the voltage potential between two points instead of directly reading $V_{bc}$, you would just take the differential of $V_{b}$ and $V_{c}$

$V_{bc}$ = $V_{b}$ - $V_{c}$

it requires more math but I can take many readings, record them and do the math later. usually turns out much faster. and you never get the polarity wrong....

assuming your working on a rather simple circuit with few to no reactive elements which I assumed since your picture had DMM style probes.

Last edited: Dec 13, 2013
19. ### ErnieM AAC Fanatic!

Apr 24, 2011
7,331
1,572
In circuits 102 you'll be exposed to voltage potentials that are not constants.

In logic 102 you'll see circuits where signals change all the time, and the change with respect to time is critical. For example, a data and a clock signal where the data only makes sense when aligned with a clock signal.