Do you have a LNB menu?
If the LNB is now defined as 'universal' (meaning LOFs 9750/10600), then search for the possibility of manual setting of LOFs. Most normal receivers have that option, I would think.
You can allways change the settings back ~ no harm done, this way.
Otherwise the only way to test is by transponder scanning with a 'shifted' frequency; or (a bit drastic ~ if no other possibilities exist) erasing the transponder list and do a blind scan ~ but receivers without the prior options would also not have a blind scan, possibly?
In the worst case you won't find a difference, and the test leads only to confirmation that that was not the problem.
However, I've frequently seen topics of people buying new LNBs, while the only problem they had could be solved by changing some frequency value, and the LNB could function on for some years. Me personally, I prefer that kind of solution.
Greetz,
A33