Made it to walk in and out with out getting wet.
Some things are made just to be assembled once and that's it, unfortunately even this product is one of those.
While there is some simplicity in the circuitry what ATTEN did totally wrong is the dimensions of the holes of regular parts as for example the capacitors.
Parts removal is a pain in the ass.
Electrolytic capacitors are made by an unknown brands called as JWCO and after some research over internet I just find some comments that is just a bit better than totally cheapest ones.
I did ESR measurements one 47uF 35V seemed degraded and I did replace it by a better Nichicon.
The true problem about the back-light was the hand soldered LED, which took me long time to isolate as problem because it did seemed as soldered.
What really happened is that PCB holes does not match with the specific LED system that gets behind the display.
So eventually ATTEN used a person to patch the problem, but the next problem is that LED leads are sort, so to travel around the PCB and be soldered as it should be, the only way to do that is to bent the leads with tremendous accuracy, which it did not happen here.
Generally speaking I am kinda disappointed about finding inside such budget capacitors, and fragile push buttons, which if you are not careful when using hot-air rework station these could melt.
Even so this adventure reminded me how crap was my older soldering station, which I had to use in this repair.
My opinion today is that I will never trust ATTEN about buying the supposed more expensive with more features soldering station.
By such build quality inside they definably do not respect their customers.