Hi,
Thanks for sharing — I know how frustrating clogged nozzles can be, especially with low-volume use.
You've already done thorough cleaning, so at this point a partially blocked black nozzle seems likely.
Sometimes multiple deep cleans (with rest in between) can help, but if not, replacing the...
If the power supply has already been confirmed to be working, but the printer still shows no lights or sounds, it might point to a problem with the mainboard or internal circuitry. At this stage, further inspection by a technician could be the best option.