It is possible that the heavy load carrying capacity exceeds the switching power supply due to the specific output power of the switching power supply. For example, 12V3A, only 36W output power, if the load current is greater than 3A, then its output voltage will be low.
Disconnect the load, and then measure the output voltage of the 60W switching power supply. If the output is still abnormal, the switching power supply is very likely to have an internal failure; if the output is normal, connect to an ammeter to measure whether the load current series power supply is too large. When the current is too large, when a part of the switching power supply makes the output led power supply insufficient, the output current of the switching power supply needs to be replaced. If before the normal output, describe a back-end load short-circuit fault, resulting in excessive load current.
2. Low input voltage
The input voltage range of the switching power supply is wide, usually about 100V~240V. The AC input voltage is abnormally low to 100V or less. This is rarely the case. It can be measured at the input voltage end, and the input voltage may be caused by the contact line difference.
