BCL Amp or Weihong pcb

As far as I know Pin 1 5v, Pin 2 and 4 GND and Pin 3 signal +. Measure between pin 1 and 2 or 4 and where you see a diode that is the PSU. The other 2 pins are signal + and signal ground. On my cheap ass oscilloscope the signal looks like a PWM which has 1.44Mhz no load freq. and when the duty cycle increases by touching the sensing pin it drops to 400Khz. And after this point I increased the PSU voltage and at around 9V it was dead. The experiment will continue after I recieve another BCL amp from CN.

Because, in this case, in order to be obvious, it needs to be visible. That board was potted in resin. Not to be rude but you seem to be a bit off topic. 

It woul d be nice to know what this circuit board is used for and what is your intended application.

Some people on the forum will know what this is.
It is the capacitive height measurement sensor for a fiber laser. It is connected to either a FSCUT or a BCS100 chinesium board. It has no info regarding the signal type, voltage level or pinout. Just a GX16 connector. As far as I know no.one has removed it from the resin up to this point.
Now the 5v label on the board seems obvious and going to 9v sems just plain stupid but keep in mind that this was covered in a thick layer of black hard goo also known as epoxy resin.

Keep in mind that hot water goes as far...so some inductors are in the trash:))). The GND may seem common but actually if you measure it there is also an inductance between the two grounds.
Now waiting for a new batch of BCLs to do further testing.
Yes, two topics and a lot of guesstimation. Now it is clear that it needs 5V(stupid decision over a long run of cable, I might try to use a nano to move the signal over RS485 or ETH)
If you knew what it was why did you ask me why 9v. I thought it was 24V, the logical decision over a 15-20m run of cable.

We did get this working with details at: forum.linuxcnc.org/plasma-laser/51568-in...e-sensor-to-linuxcnc. We also ended up depotting one and modeling the circuit to figure out how to interface with it. Although the pins on our depotted board were not labeled, so we were still guessing at the +5V, but it does work. I believe the inductance between the two ground pins in our case was an RF choke. You can see half of the board we depotted here www.reddit.com/r/AskElectronics/comments...onent_could_this_be/

Well what do.you know!!! Thank you. I searched all over the internet but could not find any info so I ended up depotting one myself. My laser setup is going on ethercat so this should be fun. The only board i could find for ethercat with a decent price has a 10bit ad 0-10v. So i need to figure a way to convert variable frequency ro 0-10v.