Review: PCBite circuit board holder and probe

The PCBite kit holds your circuit board in place while you probe it, reducing the risk of short circuits.

Recently, I’ve had to test and characterize many small PC boards, including embedded processors, DC-DC converters, and other wireless-related products, for EMC issues. I’ve never really had an easy way to keep these boards from moving around on my test bench.

While attending the EMC & Compliance International Conference in Newbury, UK. One of the vendors, Telonic, demonstrated an affordable universal test fixture holder and a probing system called PCBite from the Swedish company Sensepeak. This product is also available in the U.S. from Saelig.

PCBite kit hold circuit boards — Figure 1. I ordered the PCBite kit, which includes two 350 MHz scope probes, single probe wires, and several magnetic probe holders.

PCBite is a modular board-holding and probing system that can be configured in many ways. Figure 1 shows the basic kit, which includes a steel plate with a non-conductive covering. Magnetically attached clamping posts hold the board in place, and insulators help isolate the clamps from board circuits.

PCBite offers three main options for probing:

Oscilloscope probes with magnetically attached gooseneck holders that are flexible yet stiff enough to hold the probe in place. The probe bandwidths available are 100, 200, 350 MHz, and 500 MHz.
A pack of wires with connector pin sockets that fit the common pin connections on embedded processors.
DMM probe wires with banana plugs.

There are several options and configurations. I bought the Sensepeek PCBite Kit with two SQ350 350 MHz scope probes and 4X SQ1 single probe wires for $320. The kit came with several probe tip types, some of which were spring-loaded pogo pins. The 350 MHz bandwidth probes were the best match for my portable Micsig TO3004 tablet scope and a reasonable match for most of my applications using the Rohde & Schwarz MXO44.

PCBite test setup with oscilloscope — Figure 2. Test setup showing the PCBite test fixture, probing solutions from Sensepeek, and a Rohde & Schwarz MXO44 scope.

Figure 2 shows a typical test setup for measuring the time domain and spectral response of a 10 MHz clock on a Picotest test board.

I found that PCBite’s four clamping posts connect strongly to the base plate, and it takes quite a bit of finger pressure to release the clamp as you fit the board. That’s a good thing, for it means there’s no danger of the circuit board coming loose. The gooseneck probe holders were stiff enough to hold their shape, yet positioning the probes was easy. The posts come with a pack of round washer-like insulators to avoid shorting out board traces. Figure 3 shows a close-up of the probe.

PCBite probe closeup — Figure 3. A closeup of the PCBite, showing the scope probe monitoring the 10 MHz clock and one of the spring-loaded posts holding the board under test.

One minor quibble was the spring-loaded pogo pin probe ground connection. While the designers had the right idea, it wasn’t implemented well enough for practical use. In Figure 4, the pogo pin is slightly longer than the probe tip.

Thus, the spring-loaded ground connection would push the scope probe away from the board, requiring you to apply pressure to the probing connection, which, of course, obviates the need for a probe holder. Finally, the steel wire holding the pogo pin was stiff enough not to stay in place well as you positioned the scope tip. Fortunately, they did include a short ground tip without the pogo pin and used a thinner steel wire for better positioning.

Long pogo pin — Figure 4. A comparison between the short-ground connections. Note the pogo pin is slightly longer than the scope probe, making a hands-free connection difficult. The other ground connection supplied did not have this issue.

Overall, I think PCBite is a reasonably affordable solution for securely holding a board under test and hands-free probing. While useful for casual measurement, there are much higher quality and bandwidth probing solutions on the market.

I was really impressed with the magnetically attached probe holders and board mounting posts. There is no risk of them coming loose. I also liked the flexibility yet sturdiness of the probe gooseneck holders.

As for the Pogo pin-style probe ground springs, I’ll just order their conventional ground springs. This will come in handy for most of my bench-top EMC measurements and troubleshooting.

Recommended for casual or hobbyist measurements.