Haze the New Guy
The next stop is the Autiotek AT-PS4. Our first impressions are good, other than the initial odor of cheap petrochemicals. There is a three-wire power cord, suggesting a ground. There is a fuse holder, suggesting fusing. Since résumé padding is a real thing, we will need to get inside to validate these claims. That task again presents us with six screws, in one way better than the old unit, and in another way worse.
As clean inside as it was outside.
Already this is looking very nice. The six screws are arranged so the top cover braces the front and rear panels, preventing the disturbing flexing that occurred when we examined the first unit. Unfortunately, self-tapping screws were used, and these were already spinning a bit in their holes before our experiments were done. Soft materials will do that, which is why plastic and soft metal panels in cars and machinery often include those little spring-steel clips for catching the screw threads.
The interior layout is very clean. The total separation between the high and low-voltage sides is exactly what we want. The transformer looks to be good quality and the fuse holder is definitely being used. The ground wire is actually connected to something, an otherwise frequent oversight in direct-import kit. Even better, it is attached to the chassis and a transformer leg at a single point, where it should be. On the low voltage side, the wiring is clean and bundled, the PCB layout is spacious and thoughtfully designed even if the material seems a bit cheap, and there is plenty of insulation, even on parts that don’t necessarily require it. Someone planned this layout instead of just throwing things together.
Welcome to the regulator side.
The problems emerge in the details. On the low-voltage side, complaints are minor. The red multi-way terminal is visibly deformed. A power resistor operating at high temperature is mounted on the PCB instead of being well ventilated elsewhere, although it is mounted high and won’t bake components above. Useful vent holes on the bottom were drilled in exactly the place where the transformer body blocks them, making them useless. And the more disturbing thing was the discovery of a few poor solder joints on the PCB. These would have eventually failed, and that repair led to a second discovery: the wiring on the low voltage side is copper-coated aluminum.
Copper-coated aluminum is solely a cost and weight-saving measure. It can be tolerable in some low-voltage applications where things never move, but it doesn’t meet formal electrical standards in many jurisdictions and is mechanically weak. Just try offering a box of mysteriously cheap, off-name plenum cable to a network professional who has seen the stuff before. We thought about doing so as a side-feature for this review but didn’t want to risk being stoned to death with Mountain Dew bottles.
Fortunately, the mains power cord turned out to be actual copper, so no black mark there. Instead, we found something stranger. The cord employed the IEC color scheme of brown, blue, and yellow/green, but the blue wire turned out to be connected to the hot lead from the mains. Even more strange, the blue lead was correctly wired (deliberately, or otherwise) to the fuse holder. Unfortunately, the output from the fuse did not go to the switch. Instead, it was tied to the transformer, the transformer output went to the switch, and the switch then returned to the mains neutral using the brown conductor.
And what does give it a genuine black mark is that the ground, though present, was tack-soldered to a terminal. A proper ground lead must be compression crimped into a suitable ring terminal. The reason is that in a worst-case failure, high currents could flow through the ground long enough to loosen the solder. The ground lead should be the very last thing to go as the entire device is burning to the ground, and only a compression crimp guarantees that level of endurance.
Not quite grounded in reality.
If the internal color swap with otherwise correct polarization had been the only thing wrong, we could have at least rated this “not dangerous” while still noting the other issues. But a switched neutral is poor practice and the tack-soldered ground is a definite “no.” We appreciate the effort that did go into designing this device correctly but in the end, it lost its passing grade on a couple critical points.