Checkpoint in case of switching power supply failure

When the output voltage is low

The output voltage setting value is low

The output voltage may be set too low with the output voltage variable volume or the output voltage external variable function.
Turn the variable output voltage volume clockwise to increase the voltage. If it is turned too much, the overvoltage protection function will work and the output will stop.

Used below the minimum output current

For multi-output power supplies, there is a minimum current value for the main output voltage (V1). If it is used below the minimum current value, other output voltages will become unstable.

For example, in the case of a 3-output multi-output power supply of 5V ± 12V, it is often the case that a transformer is used to make 5V and ± 12V is made up of three terminals. In that case, the voltage of ± 12V becomes unstable unless a certain amount of current is passed to 5V. The minimum output current is stated in the specifications.

* Some multi-outputs do not have a minimum current value specification. Single output power supply is not relevant.

Not input with the correct input voltage

It is the same as “Incorrect input voltage” when no output is performed as described above.

Overcurrent protection function is working

This is the same as “Overcurrent protection function is working” when there is no output as described above.

If the output stops immediately

Overvoltage protection function is working

It is the same as “Overvoltage protection function is operating” when no output is performed as described above.

Over current protection function is working

It is the same as “Overvoltage protection function is operating” when no output is performed as described above.

Thermostat protection function is working

The symptom is that if the power is turned off and then turned on again, the power will operate, and after a while, the output will stop repeatedly.
It seems that thermostat protection is working due to the rise in the internal temperature of the power supply.

Thermostat protection is often not listed in the catalog. This is because the parts vary widely and it is difficult to specify at what temperature the thermostat protection operates, so it is not listed in the catalog.
Thermostat protection is the last bastion when other protections fail.

In this case, it is necessary to lower the ambient temperature so that the heat of the power supply can be released.

When the output voltage is unstable

Incomplete terminal connection

The output becomes unstable due to loosening of the screws on the output terminal and the terminal on the load side, poor contact of the connector, etc.

The screws will loosen naturally, so check for looseness.

Overcurrent protection function is working

It is the same as “Overcurrent protection function is operating” when no output is performed as described above.

Used below the minimum output current value

It is the same as “Used below the minimum output current value” when no output is performed as described above.

Summary

If the switching power supply fails, it is used incorrectly if it is new.

If the power supply you have been using up to now suddenly stops, it will reach the end of its life if you use it for 4 to 5 years.
If it is 3 years or less, the following causes are possible, so please check it.

This is the end of the article.

Thank you for reading.