David L. Huffman
The BLS supplies are quite complicated if viewed as simply a
DC power source. These are some of the things to look for when
troubleshooting a faulty supply.
- Common things to look for if there is no output.
- Missing External Interlock. This can be overlooked since the
LED only lights if the signal is present and the reset has been
- Missing Selector Module will cause the supply to appear to be
good, i.e. there are no fault indications, but there will be no
- Supply trips after a few moments of operation. This will
happen if the water is not flowing. Check that the water hoses
are completely connected.
- Under voltage trips are usually caused by one of two
- A raw supply that is insufficiant. A blown fuse or tripped
- A faulty control power board. (see Control power board
- Control Power Board problems are usually bad three terminal
regulators such as broken pins. We have had a small transformer
- If there should happen to be a water leak inside the chassis,
water generally condenses or drips on the temperature sensors on
the output modules. The indication of a very high temperature on
one side or one set of outputs is the usual fault.
- A phase fault usually indicates that the AC plug is
- Supply appears good but there is no output- check that the
Module Select plug is in place. This plug sometimes gets left on
the supply that is removed.
- No External Interlock- look for water flow, drip or smoke