@Phaedrux

Yes its same board.

@T3P3Tony

Ok I know at least it's a D3m board issue. I borrowed duet mini from a friend. I plugged everything in and powered it up - it works as it should :/.
So for sure something with the board

@T3P3Tony

Its the best I can get with my phone.
For me it looks normal.

@Phaedrux
I tried that at very begining. Even before writing here.

I ran many tests tonight.
I unplugged everything from the board and plugged it in one by one - I didn't notice that anything had an effect.
I see that the motors sometimes respond. Sometimes. They don't move in the correct way - for example, they just whirl. But a piece move by jumping.
I could not find the correlation. I unplugged and tried to check each one individually - on each it happens - either it does not work at all or works completely incorrectly.

Occasionally, from time to time, there is a message about a driver short circuit. But not every time. Happens with different drives.

@droftarts

The printer was working, printing. During one of the printouts suddenly the drives stopped working. At the time I did nothing about it because it was nearing the time of moving and I did not want to start it. Then everything slipped, and now that I finally have time I set about getting it up and running.
That is, there was a failure, the printer in such a state stood protected for a good few months.
After starting it up, basically after checking a few obvious things - whether there was a short somewhere, whether there was power, whether the fuse blew - I immediately wrote here.

If it is a UART issue then what is the prognosis?

@droftarts

Are these pictures good enough? Do you need higher magnification or sharpness? If you say which part, I can try to do a macro.

@Maciek
I have the impression - but I'll check it when I have access to the printer - that one of the indicator LEDs - specifically the blue one glows weaker than the other three.
The voltage on the power supply is within the normal 24V.
Are there any measurement points on the board where I can check if everything is OK?

@dc42

I disconnected the daughter-board, started the printer - it did not change anything. I tried to move the Z-axis - (I did fake homing M92 Z) but it did not help.

To answer your question - the daughter board was mounted correctly - using standoffs.
In general, the printer is decently wired, without any tangles, the wires poised, used terminals, ferrules, etc.

I did update to 3.4.5 - nothing changed.

For me personally, it is interesting that if I move , it appears to me as if the axis is moving - there is a set speed, there is a top, even the position of the axis according to dwc changes.
(now Z is -5 because i did G0 z-999999 just to make a screenshot)

Any more ideas?

Is there anything else I can check to determine what might have happened and how to fix it?
I would like to determine if something can be done or look around for a new board.

@DIY-O-Sphere
nothing interesting

; config-override.g file generated in response to M500 at 2021-10-04 21:45
; This is a system-generated file - do not edit
; Heater model parameters
M307 H0 R0.756 C301.148:301.148 D2.76 S0.60 V23.6 B0 I0
M307 H1 R1.835 C219.900:173.600 D7.75 S1.00 V24.1 B0 I0
; Workplace coordinates
G10 L2 P1 X0.00 Y0.00 Z0.00
G10 L2 P2 X0.00 Y0.00 Z0.00
G10 L2 P3 X0.00 Y0.00 Z0.00
G10 L2 P4 X0.00 Y0.00 Z0.00
G10 L2 P5 X0.00 Y0.00 Z0.00
G10 L2 P6 X0.00 Y0.00 Z0.00
G10 L2 P7 X0.00 Y0.00 Z0.00
G10 L2 P8 X0.00 Y0.00 Z0.00
G10 L2 P9 X0.00 Y0.00 Z0.00

@Phaedrux
It was working like a charm on that firmware. Now its dead.
Im waiting for more suggestions.