Hi.
A PC power supply is a good alternative. Do you know how to make it start?
Another power supply unit will be used as an element for diagnostics.
You can trust it because you know it is working.
The controller board
(I don't know which version you have) had an automatic switching mechanism for 5V power supply.
In my opinion it caused problems for users who are not experts in electronics. I have no confidence in him.
If you analyze the circuit diagram you will track it.
You are also asking about stepstick modules.
A lot of problems can be the reason for weak or insufficient electrical contacts in the socket. Pay attention to the position of the knobs of the adjustable mounting resistors.
For some time, the PCB electronics assembly was so poor quality that it was a problem.
Some components
(sockets) were mounted incorrectly, there were many cold solders.

This created many problems for customers, especially the inexperienced, and severely affected the company's reputation.
You may also find that when you use your power supply everything will work properly.
Please pay special attention to how the motor sockets are mounted. How the wires in the motor cables are connected.
I understand that you shouldn't deal with such matters because you bought a finished product and it's supposed to work ...
However, in view of the above, you need to check all the components step by step.
However, on the other hand, you will know the exact construction of the printer, nothing will surprise you in the future.
Personally, I wish you perseverance, and I firmly believe that you will solve all your problems.
