PCBite: Probes that hold themselves

A new test of PCBite filmed by Roger, an Elektor reader who checks if this accessory lives up to its promises. Does it give reliable, hands-free measurements without mechanical linkage, held firmly in place by gooseneck arms? Do the befits of this accessory justify investing in it? The answer to these questions is set out in this video from Kainka Labs.

A few weeks ago, we presented in these columns an invention worth of interest for any electronicist only has two hands, but lots of measurements to make on a board being tested. We called this tool “The missing link between crocodile clip and contact point”.

No mechanical attachment

For the electronicist, the idea of not having to hold his test probes is attractive, but he will rightly question the quality of the electrical contacts. This last point is already a known issue with crocodile clips and wire-grabbers. What would you say to even more mechanical attachment? Can an electromechanical contact device be both flexible and stable? Immobilising a board on a workbench is easy with the aid of a “third hand”. This is another pair of arms that holds measuring probes firmly, but without restraint. The idea of a “fourth” hand which, with precision, holds the measuring probes against test points without attachment or losing contact, is very clever, but the seasoned electronicist, with furrowed brow, will want to see it working first.

Nothing in the hands, nothing in the mouth

This is where Roger, one of our faithful readers, comes in. He bought a PCBite in the Elektor shop. Without hiding his initial skepticism, he tests these gooseneck arm probe holders for Kainka Labs. He films the immobilization of the spring-loaded probe tips held in place against the pin being tested. And then he measures.
Will the stiffness of the flexible arms holding the probe tip be enough to hold it in place and make a reliable contact? Will the magnetic force that holds the base of the arms and determines the force applied be enough to resist the pressuer of the contact springs? Is the whole assembly that holds the board to be tested, the probes and the base really stable?

Is the PCBite really worth its price?

These questions are very justified and are answered in this video, which I recommend watching. It’s not long, and starts off with Roger replying to more questions no less thorny than the aforementioned ones: given the price of this accessory, is it really worth it?

Mastech MS8911 Tester

You will also find in this video a demonstration of another accessory recommended by Elektor, the Mastech MS8911 tester. The success of this SMD tester has regrettably caused it to go out of stock. At the time of writing (mid-March 2019), the delivery time of the Mastech Tester is abnormally long. This delay does not however affect the availability of the PCBite, which is normal.

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Discussion (1 comment)

JohnHind 5 years ago

Thanks Roger, that was very informative. Mine came with four 'crown' pogos in addition to the four 'pin' pogos fitted to the little PCBs ('crowns' are better if contacting PCB pads rather than component legs). Until I viewed your video I did not realise these pogos have tiny sockets. I had assumed they would have to be exchanged by soldering and felt short changed that they were not supplied on their own PCBs. Now I know, I feal much happier with the kit, although at the price I still think they could have fitted the insulation washers in the clamps. (They are fiddly to fit and the need for them to be split could have been avoided by fitting them during assembly of the clamp). Also they could have supplied rubber feet and an ESD bonding clip for the base plate.

I too was skeptical that the goose necks would be stiff enough to apply enough pressure to the pogos, but actually that is not how they work. The cylinder that supports the probe PCB is solid and heavy and it is actually gravity that supplies the contact force. The goose neck is only required to hold the probe in position parallel to the plate and at orientation. Very cleaver!

I'd like them to extend this system with an ESD clip and a goose neck LED spotlight on the same type of magnetic base.

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