Perhaps the switching supply is not able to supply enough current via one or
more outputs, and is shutting down.

Many off the shelf supplies will deliver a hefty dose of 5v, much less in
the way of +12v, and often way less than the +12v figure for the -12v.


Gareth.



wrote in message
...
I have an old IRIS 4d/35 system with touchscreen capabilities and display
is CRT type.

Recently we upgraded the system to run on LCD displays where we needed to
provide the touchscreen controller with a separate power supply since the
power for the controller was previously drawn from the CRT power supply.

However when a new switching power supply was used the touchscreen did not
work. Reverting back to the supply from the CRT works flawlessly.

The supplies required for the touchscreen controller are 12V, -12V and 5V.
The CRT power supply had a common ground and so does the new switching
power supply.

Any idea what could be the problem with the new power supply. Any advise
would be very much appreciated.