All my impressions for Black MY switches come from two typewriters, the Triumph Adler Royal Alpha 110 and Satellite 8.


A word about the external design
I didn't take a picture of the bottom of the keyboard, but MY switches aren't soldered in place. Black MY keyboards consist of five parts: the switches, a thin mylar PCB over layer, a thin mylar mid layer with no circuitry, just holes cut in it, a thin mylar PCB under layer, and a backplate, in the case of the Royal typewriters it appears to be steel. The switches are anchored to the plate by a pair of legs on opposite corners of the switch. Those legs are melted and mushroomed out. As such, the only way to remove a switch is to cut off those little mushroomed bits of plastic. When you actuate the switch, a small metal bar moves down and presses the top and bottom mylar sheets together, completing the circuit. Due to the design, MY switches generally have to be bottomed out which is one of the sources for their less than amazing feel.

One of the most interesting differences with the Black MY switch is that every switch has a stabilizer wire mount built onto it. If you look closely, you can see the little points where they grab the stabilizing wire.


Each switch has the Cherry logo emblazoned across the top and each one has a number on the bottom. I have no clue what the significance of that number is, but I'm guessing that it's nothing important based on the random distribution of numbers on the switches.
If you want to open up the switch, you have to find something that's small enough to slide down the little cutouts and grab onto two nubs on the bottom so that you can pull it out. This design, while making it easier to work on the switch, makes it much easier for dust and other unwanted things to work their way into the switch.
It's also interesting to note that, like modern Cherry switches, the horizontal crossbar on the stem is a little thicker than the vertical one. If you place the cap on sideways it fits much tighter.
Stabilizers
The stabilizers on Black MY switches are also interesting. While they have a similar look to Costar stabilizers and Alps stabilizers at first, they are considerably more finicky than both.

When you look closely at the stabilizer feet, it becomes apparent that they are only meant to work in one direction.


If you put them on the wrong way, the switch will basically lock itself in the depressed position.
A Word About Internal Design
Just like MX switches, MY switches consist of four main parts, housing, stem, spring, and leaf.
The stem/slider has four guides on the corners to help keep torsional movement in check and to guide the switch when it moves up and down. One corner of the stem has a larger guide that the others, so the switch can only be put in one direction.


The spring for the switch drops into a hole on the top half of the stem and there's a nib on the bottom half of the housing that it rests in. The spring is actually quite small, smaller than an MX spring. I'm actually wondering if you might be able to fit it in some Alps switches.


Switch Feel
To start, Black MY switches feel weird. In a way they're contradictory. When you just play with one, it's hard to see why people despise the switch. Even when you first start trying it out, you sit there going, this really isn't as bad as I always hear. Then you start depressing the switches all the way down to the point and of actuation, trying to type and you realize, holy crap are these thing fatiguing.
Blacks are heavy, but they have nothing on Black MY switches. Much like Ghost Blacks, Black MYs are lighter at the top and heavier at the bottom, but that's where the similarity ends. Black MYs almost feel light at first. By the time you reach the midway point you start to go, ok, these things have some resistance to them. Then you hit that last quarter throw of the switch that you have to hit before you bottom out and actuate the switch and you start wishing you were Bruce Banner so that instead of raging at the switches, you'd become the Hulk and laugh at how puny they are. The best analogy I can think of to describe how it feels is packing your sleeping bag into a compression sack. If you've ever been camping or backpacking and used one, you should know exactly what I'm talking about.
I have to admit, there is some hyperbole there. It's not that Black MYs are bad, it's just that they're not good. If I was given the choice of chopping my hands off or only using Black MY boards the rest of my life, I'd pick the MYs. It wouldn't be pleasant, but it wouldn't be so bad that I couldn't use it. Hell, if you're one of those people who thinks MX Blacks aren't heavy enough, you may actually love the switch. To me, they just feel like they're fighting me too much though.