The super probe miniaturized
Designed by Mr Carlson
Miniaturized by sv3ora


Here is my version of Mr Carlsons Super Probe a simple but very effective probe that can be used for finding faults and problems in electronics circuits and components. The probe is contact-less, meaning that you do not have to make a physical connection to the components and circuits under test. It is so sensitive that it can detect SMPSU noise, even from the quietest LED lamps, from a meter away, it can detect noise from small NE2 bulbs half meter away, mains wiring noise behing the walls and in some cases it can even detect internal components failures without any physical connection to them or removing them from equipment. Thats a magic problem-solving probe for anyone that repairs electronics.




The schematic of the probe is split into two parts which are shown above. I built mine as above and the only changes I did, were that I used BC549C transistors in the circuit and replaced the opamp with an LM386 in high gain mode. I also used 10K potentiometers around the audio amplifier and fed the circuit from a 9v battery instead.

Everyone I know, has built this probe as Mr Carlson states, in two separate enclosures. I took the challenge to build my version in a single enclosure, actually inside the same probe, yet using only through hole components. I even included a battery and a speaker inside that enclosure!

The complete probe is shown below. I used small plastic potentiometers and their shafts have been trimmed to fit into the enclosure, with a hole on it so that they can be accessible with a screwdriver. I could use knobs, but I thought to keep the size of the probe down to minimum. The probe has been built inside a PVC tube. Inside it, there is a double-sided PCB that slips through it and stays in the middle of the tube. One part of the circuit is built on one side of the PCB and the audio amplifier on the other, as I thought this would provide maximum isolation and prevent feedback. The PVC tube was screened with a piece of copper sheet around it and also in the front of it, where the probe tip extends. Note that the screen must be grounded too. The buttons and potentiometers/trimmers for the different functions are accessed through holes in the PVC-copper tube. To hold everything in place, a piece of thermal shrink tube was used around the whole probe.


The speaker was embedded into the tube and behing it there is the 9v battery. The white plastic ring (taken out of a pills enclosure) slipt firmly into the tube and holds everything into place. Then the battery needs replacing, the ring us pulled out and the speaker too. The battery is the plugged out of the battery socket, which is soldered vertically onto the circuit PCB. The battery socket is taken out of an old 9V battery, after dissassempling it. The LED if mounted directly behind the transparent speaker and lit through it. I sused a small blob of hot silicone glue to keep the led firmly attached behing the transparent speaker diaphragm.


The front of the tube is also screened by a disc of copper, cut into shape. Note that I  left a small notch on the copper disc,  so as to be able to slip out the circuit from the tube when needed to make changes/repairs to it. The disc is soldered to the rest of the screen around the tube and also to the  braid of the coaxial cable of the tip, using a small lead wire. This way, the external screens of the probe, are grounded and connected to the internal ground of the circuit. The probe tip is made exactly as MR Carlson states in his video. In my version, the negative wire is mounted directly to the point where the disc connects to the braid of the coaxial cable of the tip.


As of 17 May 2023, I have not yet used the probe to do any repairs, however this project shows clearly that such a probe can be made highly portable even without using SMD components. Here is s small (6.5Mb) video, showing the super prope being able to pick up audio by the meter movement of the Collins 51S-1, by bringing it near the meter. Yes, it is that sensitive. Happy repairing!

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UPDATE 14-Jul-2024

Here is another way of making this probe in a self-contained unit. I used a case out of those first aid car kits. It actually turned out very well, as the batteries can be easily replaced and repairs can be easily made. The probe works great. I used a longer piece of coaxial cable for the probe, so I can stick it inside circuits easily. But the probe is self-contained and portable. This time I did not use any ground aligator clip, as the probe seems to work well even without it.




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