Andre Jute writes:

I've got a cool little Wrench Force floor pump that
will accept Schrader or Presta. I've used it for
over a year exclusively to inflate my Presta road
tubes. Got the kids bikes for Christmas, pumped
them up (Schrader valves), and now (several weeks
later) the pump won't blow air out the Presta hole
any more. It's supposed to be "auto sensing". Is it
just buggered? What would you all try to debug
this problem?

Rather than all these tiresome workarounds, why not
just buy [...]

Buy stuff. Solution #1 in the bicycle world.

--
underground experts exiled