Signstek MESR-100 V2 Auto Ranging in Circuit ESR LCR Meter Capacitor/Low Ohm Meter Up to 0.01 to 100R, Support in Circuit Testing

Love this thing, but the leads slip around when trying to clamp them and they are very short they should be longer and have the ability to put tiny probes on as well!!

The MESR-100 may not look flashy compared to modern touchscreen test equipment, but it has earned a permanent place on my electronics bench. This is one of those classic tools that does a specific job very well, and if you work on electronics repairs, it's incredibly useful. The primary reason I use it is for troubleshooting capacitors. A capacitor can look perfectly fine and even measure close to its rated capacitance, yet still have excessive ESR that causes a circuit to malfunction. The MESR-100 makes it quick and easy to identify those problem components without a lot of guesswork. I've used it on power supplies, consumer electronics, and various repair projects where tracking down a failing capacitor would have been much more difficult with a standard multimeter alone. One of the best features is the ability to perform many measurements in-circuit. Instead of desoldering every suspect capacitor, I can often get a good indication of component health directly on the board. That saves a tremendous amount of time when troubleshooting. I also use it when selecting replacement components. When comparing capacitors from different manufacturers or evaluating parts from my component inventory, it's nice to have an easy way to check ESR and resistance characteristics before installation. It provides an additional level of confidence that the parts going into a repair or project are actually suitable for the job. Operation is refreshingly simple. There are no complicated menus or lengthy setup procedures. Turn it on, connect the probes, and start measuring. The auto-ranging works well, readings are easy to interpret, and the instrument does exactly what it was designed to do. While I own more advanced test equipment, the MESR-100 remains one of the tools I reach for most often during repair work. It's a classic piece of bench equipment that has stood the test of time because it solves a real problem quickly and effectively. If you repair electronics, troubleshoot circuit boards, refurbish equipment, or simply want a better way to evaluate capacitors, this meter is absolutely worth having. Simple, reliable, and extremely useful.

What Makes It So Useful (For Real Work) The biggest win for me is in-circuit ESR testing. I don’t have to desolder every capacitor just to check if it’s bad. I can probe directly on the board and get a solid answer in seconds. That alone saves a ton of time. It uses a ~100kHz test signal, which is important because it matches how capacitor ESR is actually measured in real applications . Why I Trust It More Than a Multimeter A regular multimeter might tell me capacitance—but that doesn’t tell the full story. This meter shows ESR (internal resistance), which is usually what actually fails in caps over time. Low ESR → good cap High ESR → bad cap (even if capacitance looks fine) That’s huge when troubleshooting unstable power supplies. Where It Helped Me Most I’ve used it for: Xbox PSU repairs (huge here) Motherboards and GPUs Old TVs / monitors Random SMPS boards It’s especially useful when I’m chasing intermittent issues or unstable voltage rails. Fast, Simple, and Repeatable No menus, no complicated setup: Touch probes → instant reading Auto-ranging handles everything Built-in ESR chart helps quick comparison It measures roughly 0.01–100Ω, which covers most real-world capacitor failures

Works well to identify defective capacitors. As many people have said, the leads are not just too short, they are tied to close to one another. The leads need another 4" and the separation needs to be another 2" to be able to get to awkward connections.

This device has truly simplified the task of testing capacitors that are part of a circuit. It's the go-to solution if you don't want to go through the hassle of desoldering components just to perform a basic capacitor check. The auto-ranging feature is a lifesaver, making it incredibly easy to measure the Equivalent Series Resistance (ESR) and inductance (LCR) of capacitors while they're still soldered in. This is a game-changer for troubleshooting circuits and identifying faulty capacitors quickly and efficiently. Gone are the days of traditional, time-consuming desoldering and testing methods. The Signstek offers precision and convenience in one package, making it an invaluable tool for electronics enthusiasts and professionals. It has truly revolutionized the way we diagnose and maintain circuits, sparing us from the painstaking desoldering process. If you work with electronics and need to test capacitors in-circuit, this meter is a game-changer.