K375s changed to left shift 64 + small keyboard

Main features:
1. Using the main control of k375s, borrowing from the GH60 mode of @zxvip master, you can use fn with the number keys to realize the F area function,
Fn+=volume+ Fn+-volume- Fn+0 mute Fn+123 corresponding device 123 
2 .Added a numeric keyboard area, I really need numeric keys.
3. Use the original No. 7 battery for power supply, and remove the switch (because the main control has its own switch) and the battery holder (because it takes up more space, the battery can be fixed on the bottom case, using 2+2 sections). No. 7 batteries are connected in parallel to achieve ultra-long battery life (you don’t need to replace the battery for about 2 years under normal use)
4. The main control is no longer fixed on the PCB, but can be fixed on the bottom case, which is convenient for connecting cables, because the 27-pin cable It’s really hard to buy. Some 27pins are 15cm, which can match the main control position according to the actual situation. As long as the power cord is long enough, you can connect it casually. 5. The motherboard does not have copper laying near the main control, which can reduce the signal. Interference, of course, Youlian is already very stable, it just makes the signal smoother. (To put it bluntly, the wiring is really troublesome. If you want to achieve 100% copper coverage, it will probably take several days to adjust the wiring, which is a big headache. Anyway, for this kind of board, there is no difference between laying copper and not. I laid copper just to make the board more removable, because the PCB satellite axis hole is designed, and the steel plate satellite axis can also be used. Of course I It doesn’t have to be used, but it is necessary. If I want to save money and don’t use the positioning board, then I can just use the PCB satellite axis. 6. The two power supply ports on the motherboard can be used universally, one is connected to the main control and the other is connected to the motherboard to supply power to the simulation. The chip SGM3157 is used for power supply. You can buy a dual-pin socket. If you don’t want to buy it, you can also solder it directly to the corresponding positive and negative poles (I didn’t buy it anyway).
7. The PCB uses a 5-pin hole for welding and hot-swapping, and supports a 3-pin shaft. It is convenient for you to choose whether to hot-swap or solder the axis base.
The only thing you need to pay attention to is that the analog chip SGM3157 is really too small. It is best to use an air gun when soldering. Just a little bit of solder paste, but not too much. If it is too much, it will be easy to connect the solder. . (I wasted 3 boards just for these little things. After all, it was my first time to solder and I was very inexperienced.)
The components need to be prepared with 27pin headers, 27pin cables, a resistor, and 1206 front-mounted LED lights. , as well as the SGM3157 analog chip, can be fixed with batteries or positioning plates. It does not necessarily require screws and copper pillars. This varies from person to person. Depending on your needs, I use the height of the AA battery to directly lift the PCB. Because I use a wooden casing and don’t know CNC (not because I am poor), I just use 5 pieces of wood chips to glue the casing, so I directly use AA battery as a support. I have been using it for about 3 months, and the FN key messed up once. Then I found that the analog chip had a weak solder, and then I adjusted the wiring and tried to make the via hole farther away from the place where welding was needed, and then there was no problem.