The Nokia power supply is definitely not suitable to connect the device in the water, put your hands there and be 100% sure that you will not get hurt.
Using such a power supply, I would first replace the cable with a brand new one with good-quality insulation. Then, during the operation, I would do the same as when cleaning my aquarium. When I put my hands in the water, always turn off all immersed devices: heater, filter.
Personally, I see a problem with a good sealing of the cable at the diode, the best solution should be the glue for aquariums.
Using such a power supply, I would first replace the cable with a brand new one with good-quality insulation. Then, during the operation, I would do the same as when cleaning my aquarium. When I put my hands in the water, always turn off all immersed devices: heater, filter.
Personally, I see a problem with a good sealing of the cable at the diode, the best solution should be the glue for aquariums.
