I bought two of these things based on a recommendation: one for my network switch, and one for the Roku.
Bad news: the 12v power supplies deliver only 9.56v, and that won’t even boot the Roku…
Chinese Garbage with little chance I’ll get a refund from Aliexpress.
I have a couple, and they’re nice little LPS’es for the price. Perfect for switches, routers, Roku’s etc.
Voltage is actually variable via a little flathead screw control inside the case. Yours may just have drifted. Open it up and calibrate it to 12V or whatever you desire.
I suspect this is off-topic for a PS Audio forum, though! 
It’s sufficiently on-topic. Although we may need a DC forum to which to move this thread. 
I’ll open up the case and have a look, although I doubt that they both drifted to the same value. Thanks for the tip.
What’s annoying is that both of these had a handwritten sticker on the back stating “T 12v”.
Oh well, so much for that theory - the only adjustment visible inside the case is a 10K pot. A little white block with a gold screw in the top.
Unfortunately, fiddling with the screw does nothing to adjust the voltage, beyond going from 9.56v to 9.63.
I conclude that they have a bad run of pots, and that their QA isn’t worth a darn, because someone supposedly tested these at 12v.