Note that diseqc devices like a diseqc positioner and a
diseqc switch are actually small computers which take time to power up.
So you may need to do something to send a signal to the positioner. Then the positioner is active and should be sending power to the diseqc switch.
Note that a diseqc positioner takes a lot of power to operate and may remove power from devices down the line like diseqc switches and LNB's while it is moving.
After moving positioner, may want to try sending a signal to the diseqc switch to switch it. Then switch it back again.
Also this is software stuff controlling the diseqc stuff. There can be bugs which do not control the diseqc things like they should.
Here is the actual diseqc specifications for various devices. This may help you to understand what is going on...
(Scroll down page 1/4 way to "DiSEqC Specifications"...)
http://www.tech-faq.com/diseqc.shtml