More Multiple PSUs

In regards to your posting about connecting 2 PSUs together, I have
tried this, and was unsuccessful due to timing variations between the 2
PSUs. Sometimes the primary would power up, but not the secondary.
Worse, and more frequently, the primary would shut down, but not the

I eventually solved this by using 1 ATX and 1 AT PSU, with
the AT as the slave connected to a 120 volt relay, switched by 12 volts
from the ATX PSU. This is a relay type commonly available at Radio
Shack and other similar stores.

If one needed to use 2 ATX PSUs, it seems to me a hybrid of my method
and the method used in the article should be successful. (I say should,
because I haven’t tested this idea…not yet, anyway.) Referring to the
diagram in the article, allow pins 14 & 15 of the slave PSU to be
switched by a 12 volt relay connected to the 12 volt output of the
primary PSU. This should (in theory) prevent the problem I encountered
and make the whole setup more reliable.

Email Christopher

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