All this lamentation how manuals today (which means last 10-15 years) are not real service manuals is all well but helps nobody.
This "new practice" was "invented" long time ago by Western companies (before likes of Rigol and Siglent existed).
It is a consequence of the fact that manufacturers actually stopped component level servicing in field.
It is module level servicing and old boards are either discarded or sent to manufacturer directly for internal rework process.
That is simple consequence of the fact that firstly equipment is more reliable than it was, it is more complicated than it was, and keeping service and part distribution network is expensive. It is cheaper to simply swap little board than spend hours troubleshooting. Quality of repair is not guaranteed and depends entirely on technicians skills. Work hours are sometimes more expensive than device. And then full equipment to calibrate/verify specs is needed. Also back then, many manufacturers had government contracts that stipulated component level repair process, and they had no choice. Then they realized that it is simpler, faster and most of the time cheaper to simply have replacement full devices or ready made subassemblies.
Times changed.
As to a problem that patrik96 has:
- it is probably a damage to channel output circuits.
- it can be sent to Siglent for repair, or
- if it is out of warranty, by using instructions from Service manual, it can be carefully opened ( in static safe environment ) and then you take a look. AWG has 2 channels and the one that works can serve as a reference for comparisons.