Skip to content

$14 GM328A Component Tester + 3D Printed Enclosure

GM328A_2GM328A_2I purchased a “GM328A Transistor Tester Graphic Wave Signal LCRRLCPWMESR Meter Inductance” from Banggood. It came as an assembled unit and tested out very well on my bench. Unfortunately, it did not come with an enclosure.  So, I printed on one my TAZ5 3D Printer.  In this article, I describe the component tester and some experiences with 3D Printing the enclosure.



This guy works great right out of the box, just connect a 9V battery and start testing parts.  It automatically detects the type of part and displays the data along with a graphical symbol showing it’s pinout.

I tried several parts from my junk bin and some of my known good stuff. Each was identified in an instant.

For $14 the GM328A is a great value for your work bench.  You will have to wait a while, free shipping from China does take a while.

3D Printing an Enclosure


The 9V battery dangles from its connection wires and is sure to break, so an enclosure is necessary upgrade.  I have a TAZ5 3D Printer and was looking for an excuse to try out some filament samples I’d collected.

With a quick search on Thingiverse I found the STL for a reasonable looking case.

You’ll notice that the top cover and the bottom covers are different colors.  That’s because I used tow different filament samples. The green was a low-cost PLA from China. The other was always awesome filament from Maker Geeks.

The China low-cost PLA printed fine on the top cover and there was enough left to do the bottom, but the filament jammed in the extruder.  I found that the diameter was too large, it varies too much.  I tossed the rest and redid the bottom print with Maker Geeks sample filament.

Initially, I was quite happy with the low-cost filament and was planning to order some more after that first print came out so well, but then found the filament diameter issue and just tossed the rest, lesson learned.

Problem is that the Banggood 3mm filament is actually 3mm in diameter. A 3mm extruder has a 3mm bore. The diameter of filament designed for a 3mm extruder is 2.85mm. When the 3mm in diameter filament varies to slightly thicker, it jams.

It’s not worth the headache to have jams, a print takes many hours to complete so a failed print is bad news.

The Maker Geeks PLA samples worked perfectly and I checked the diameter a multiple spots along the length, 2.85mm+0.05-0.00 for my sample.

I usually print with PETG from Maker Geeks as I don’t like the brittleness of PLA and ABS is harder to work with. The TAZ5 handles PETG well and the prints are awesome. No smell, no curling and very strong while still being workable. PLA is so brittle that it’s hard it’s even hard to sand.


Maker Geeks makes good filament and I especially like working with their PETG. I am going to try a couple of spools of Maker Geeks PLA after trying the sample on this cover.

Watch out for low-cost PLA as it seems some manufactures don’t understand what the correct diameter needs to be. Strange I know…

The GM328 is a great tool for any maker bench.

Posted in 3D Printing, Development Tools, Discovering, Interesting, Parts, Projects, Review, Scrounging, Scrounging Parts, Tips, Uncategorized, Workshop Tips, Workshop Tools.

Tagged with , , , .