SDG #054 Hiland M644 Component and Transistor Tester

The Hiland M644 is one of the many low cost clones built around Markus Frejek and Karl-Heinz Kubbeler’s open source AVR component tester firmware, and this review looks at how well a cheap kit-style implementation of that design actually performs on the bench.

The tester automatically identifies what you connect to its three test terminals, so the review works through the usual suspects: resistors, capacitors, inductors, diodes, bipolar transistors, MOSFETs and thyristors. Reported values are compared against known components and better laboratory grade instruments to see how far the readings drift, which matters because these units are frequently sold on the promise of doing LCR and ESR measurement for a fraction of the price of a dedicated meter. Capacitor ESR is a particular highlight, since it is the measurement most people buy one of these for when hunting failed electrolytics in switch mode supplies.

Beyond raw accuracy there are practical points a buyer should weigh. The M644 relies on a ZIF socket and short flying leads rather than proper probes, self calibration quality varies between clones, and the small display and terse readout take some getting used to. Very low value resistances, low capacitance and small inductances all sit near the limits of what the AVR based measurement technique can resolve, so treat the figures as a fast triage tool rather than metrology.

For identifying unmarked semiconductors, checking pinouts and confirming a part is not dead, the M644 is genuinely useful and hard to beat for the money. Anyone needing traceable component values should still budget for a real LCR meter.