teardown wavetek meterman sf10 short finder brush

There is not much inside the Wavetek Meterman SF10. The main components are two TLC555 timers and an LM324 quad operational amplifier.

The interesting part is the probe. Instead of a normal pointed probe, the SF10 uses a brush made from many conductive stainless steel fibers. You can sweep it across a group of IC pins or connector contacts and narrow down the location of a short without touching every pin individually.

The SF10 applies approximately 0.5 V with a maximum current of about 100 uA. It produces a tone when the resistance is below approximately 10 ohms.

The two TLC555 timers generate the timing and audio signals. The LM324 provides the amplification and comparison stages used to detect the low resistance path.

DIY version

For a very simple version, I used a piece of uncoated braided 10 AWG wire as the brush and connected it to a multimeter in continuity mode.

It works, although the response depends on the multimeter. Meters without a dedicated fast continuity mode respond more slowly and make the brush less useful.

Teardown, pulse measurements and DIY brush photos below.

Photos and videos