Hi there!
Recently i bought two S19 Pros and ended up blowing the PSU on one of them which lead me to open it up and replace some mosfets to fix it.
While i was at it i decided to give the rest of the miner a clean so i dove in and began doing that. While in the process of cleaning i took a note of the components inside on the main hash boards and the control board.

I have a friend in china who used to be a business partner of my cousin and she now works for a ASIC miner distributor company via alibaba. I got in touch with her to talk about the making of these machines to get some more insight.
Now in the two hour long conversation i learned quite a bit about it and i will be sharing a few of the things i learned.

The reason its almost impossible to buy miners straight from bitmain or other mining companies is because they look for high profits rather than customer satisfaction, there are underground bids which take place between large distributors and the highest bidding company gets the cake. This happens weeks before the miners are released on their website for purchase.

Cutting to the chase. The distributor company that my friend works in used to be a PCB manufacturing company. They buy BM1398BB hashing chips straight from bitmain and manufacture their own hashing pcb's by cloning one of the original ones and end up oil cooling them. Now to me, all of it makes sense since all an ASIC miner has is a control board, a power supply and a few hashing boards. None of the components are tied to one another when it comes to the hardware.

Now while its possible to clone the control board and the information on it is as follows, it looks like its quite a tedious task considering that the actual board is quite cheap to buy straight from bitmain.
CPU :  XC7Z007S-1CLG225C
DRAM : M15T2G16128A (2L)
NAND Flash Memory : MT29F2G08ABAEAWP 2GB
Network Chip : PPT PM44-11BP
The linux based firmware that is stored on the flash memory is later witten to the DRAM at runtime and is available to download on bitmain's website and can be flashed using the sd card slot on the control board.

Anyhoo, oil cooling being a whole different story, I was told that each hashing chip costs about $2 and some select few companies can hook you up with the original ones. Which leaves me with needing a control board which costs around $200 and wiring which costs around $50 including the power cords which are not included with the power supply or miner purchase. A generic 12v 20a power supply that s19 pro needs costs a mere $60 where i live. The power supply costs around $240 to $300.

Now of course i did not include the small components like heat sinks, housing, tax and shipping costs and such.
But in hindsight if i were to build the whole thing on my own, it would cost a considerably less amount of money considering that these machines are going for around $10,000 if not more, per unit, at the time of writing this post.

I've been interested in this since i learned about it a few months back, but i lack the ability to clone boards and funds to get access to a board.
My point of writing this post is to learn more about things that i might have missed or gotten wrong and/or to maybe try out this project with someone who thinks they can help or have experience in pcb cloning/manufacturing without a schematic and finds this interesting.