#TwoMinuteTeardown: Duogalia AM70 Optical Fiber Multi-Meter

2025-12-10 437 words 3 minutes

Contents

Two Minute Teardown: Duogalia A-M70 Optical Fiber Multi-Meter

While diagnosing a flakey fiber link, i ran into a situation where a basic “flashing red” visual fault finder was not sufficient. I needed to actually measure the optical power levels on both ends of the link to ensure that the fiber was not damaged and that the SFPs were operating within spec.

This was the cheapest tool that could be delivered quickly. The issue was found and fixed so now let’s have a look inside.

Many Generics

There are many many similar looking units on Ali Express and the other usual import sites. I do not know who the ODM is but it’s clear that the Duogalia A-M70 is just another rebrand of the same design.

As best as I can tell, the ODM for this is T-Better?

Teardown

The nice thing about simple devices like this is that they are easy to open and rather predictable inside. From the back, there are four self-tapping screws holding the back panel on. Removing those reveals a very simple interior.

The few unpopulated components near where the battery attaches are almost certainly for a “better” model that has a built in battery that can be recharged over the non populated USB-C port.

The square IC in the middle is running the show, the large IC off to the side is likely the display driver and the two SOP-16 chips near the ethernet port and optical sensors are for abstracting the details away for the benefit of the microcontroller.

There are 4 more screws holding the PCB to the front half of the case; if you remove them, you can get a look at the side of the PCB with the screen on it… revealing that there’s absolutely nothing special on the other side of the PCB.

And here’s a close up of the silk screen on the main controller that makes me think T-Better is the ODM.

Miscellaneous

The PCB is marked with:

1
2
3
T-Better
MINI-OPM-N32-MAIN
V11 20250617

The main ICs are:

HGSemi / CD4017C: a 10 bit decade counter to handle the ethernet cable testing functions.
NSING / NATION N32G031: Cortex®-M0 microcontroller running the show.
HGSemi / CD4051B: an 8-channel analog multiplexer to handle the optical power sensor inputs. I guess the main microcontroller doesn’t have enough ADC channels on its own.
TM(Shenzhen Titan Micro Elec) TM1621B / TM1621B: the LCD driver IC for the display.

I was not able to locate the OEM or get a digital copy of the manual that came with this thing so I scanned it myself. You can fetch it here.