29 December 2020

FNIRSI DC-6006L Power Supply and a bug

During "Black Friday|Week" 2020 I bought the DC power adapter FNIRSI DC-6006L. I would not call it a "power supply" since it requires an AC-DC adapter (like an old laptop PSU). Provided there is enough "juice" provided by the external PSU, the DC-6006L is capable of 0.1-60V output up to 6A: that's 360W in a aluminum case lighter than a smartphone and smaller than a sandwich! You can find a good description of the product (in decent English language) on their website or on the usual Far East sources that sell it.

Check out the size comparison with the Nissei SPS-250A:

FNIRSI DC-6006L vs Nissei SPS-250A.

First things first. The Fnirsi unit is not very RF silent, so it will increase the background noise if used to power an HF receiver. But it works OK as a lab power adapter.

I have found one dangerous bug. When DC is applied to the input of the DC-6006L, there appears voltage on the output even though it is configured to start in OFF position at "cold boot". It might last 100-200 milliseconds, enough to burn whatever is connected on the output! Looking at the output on the oscilloscope, the voltage reaches 6-7V regardless of the output voltage set. I did this test both with 19Vdc input on the barrel jack and with 14Vdc input on banana sockets. I have an analogue oscilloscope so I cannot do proper measurement of amplitude and duration. Just consider that an Arduino based circuit springs to life. This happens before the boot screen appears on the DC-6006L display.

On annoying thing is that the beep cannot be disabled via software. While it is useful when over-voltage/current protection triggers, you might not want to hear it for each key press or knob rotation. And it is quite loud too.

I tried serial communication without the FNIRSI software, but all I get is a string that changes in sync with operator's actions through the front panel controls.

I have drawn 45W on a resistive load without ill effects.

I paid about 30€ and it is worth it, especially if you already have a fixed DC source.