Test/Review of Component tester MK-168

Component tester MK-168







This is a fairly universal component tester, it can recognize a lot of different component types and give some parameters for them.

It is also fairly cheap on ebay







How does it look







This tester is in a box with 2 mm connections, it includes test wires.







It does also include a circuit board with a socket and a smd pattern. The box has a connector for external power, but can also fit a 9 volt battery inside.













Inside it is made very nice with connectors and a circuit board designed for this box.







The display is a standard display with 2 lines with 16 characters.







All the electronic is placed under the display.

The circuit is very simple, the microprocessor do everything. It has 3 pins connected to each of the 3 terminal, one directly for ADC, the two other pins with different resistors between.







The adapter has a smd pad, but with fairly limited functionality.















Resistors







The ohm range looks fairly good.







The display it not graphical, but because it is possible to program some characters it can show a useable symbol.







Capacitors







It cannot measure small capacitors.











Inductors







With inductors it uses the resistor symbol, but shows a inductance in addition to the resistance. It cannot measure small inductors.











Diodes







Due to the 5 volt test voltage it cannot see zener diodes above 5 volt.







There is a bug in the symboles, one of the diodes are not programmed correctly.







SCR (Thyristors) + Triacs







It cannot detect most SCR and triacs, because the tests currents are too small. Only very small types are detected.







Triac is spelled out and MT1 and MT2 is shows as 1 and 2.







BJT (Bipolar junction transistors)







It do see the diode in the transistor, but not the resistor.







There is not space for a transistor symbol on the display, the letters NPN or PNP are used instead.







The faulty diode symbol is a bit confusing to see here.







FET (Field effect transistors)







It can detect normal fet transistors, but not a deflection transistor.











IGBT (Insulated gate bipolar transistor)



Not supported







Voltage regulators



Not supported







Technical details



Components are tested with 5 volt signals.

When on the current consumption is 10mA to 27mA.

When off the current consumption is 0.







Conclusion



The tester will recognize many different components and show the values. For passive parts the precision is fairly good.

It can recognize the common semiconductors, but fails on some more special types. There is also the “problem” that any testing values shown for diodes, BJT and FETS are at unspecified conditions and the values will change with conditions.

I could have wished for a better SMD pattern.



For the money it is a good tester for leaded parts and acceptable for smd parts, but the defect diode symbol is confusing.







Notes



This tester is based on this design:

Original design article in German

Improved design (czech clone)

Software



About the testing of testers

I had no idea such versatile diagnostics devices were available at such a low price. Now I’m off to shop for one! Thanks for the review.

KuoH

There are many different models, most of them based on nearly the same hardware and software, but they are not the same.

I do plan to post some more reviews of these testers

I couldn’t wait, so I just ordered one of these GM328 because it included a frequency generator.

However, I have since found a youtube review showing the model you tested that indicated it also has a frequency counter / generator. Did you happen to check if yours has that functionality as well? I like that it has a case, but prefer one of the other variations with bigger graphical LCDs.

KuoH

I missed that, but it has that functionality.

The units with the fancy extra features require a ’328 processor that has more memory in it. HKJ’s use the smaller ATMEGA 168 processor.

I also bought a couple of the GM328 units. I wish it had the power-off button. It does the auto-poweroff, but it takes a while to kick in. I also wish it drew the diode symbol bigger.

The GM328’s have fixed high parasitic power drain that my earlier units had. They also draw a symbol for SCRs and triacs. My earlier ones just had a text display for those part.

Which extra fancy features, the bigger graphical LCD or something else? It seems from the video I found, that at least some 168 models also include a frequency counter / generator. I do like the 328’s display better, but wish I could’ve found one with a case. I might get this 168 as well, since it can do almost the same thing and has a good case and build quality. As for the power off, I guess it would be simple enough to add a switch in with the battery. It’ll be nice to have something that I can test my cheap scopemeter against.

KuoH

Thanks for the review. Will you review any of the kits available?

I am way to lazy to solder a kit together. I will only be looking at the assembled versions.