Steve : Is yours a 405?
Steve:
I know you mentioned something about a 400, but is your receiver a DSR405? If so, (in case you did not know/have this already), here's the link to your receiver's user manual
http://www.starchoice.com/english/store/download/DSR405_manual_e.pdf
All manuals can be found at
Star Choice - Customer Care - User Manuals
As SatGuyz suggested, have you tuned into those problematic channels and then going into diagnostics to check signal strength/Ebnos on those channels? The manual tells you the steps to fine-tune and you could use those in any specific channel also. A quick look at manual page 22 (page 36 per adobe acrobat reader) and if the steps listed there are accurate (Other 405 owners can chime in):
(1) go to your problematic channel
(2) Press OPTIONS on your remote
(3) Press 6 (system settings)
(4) Press 3
(5) Press 1
(6) Enter "4128" for Provider ID.
(7) That should list you signal strength in the box named 'Signal'
If all that is fine, the only other question I have is I know you had a round dish previously. Was the LNBs starchoice supplied? Were they Stacked? The new 75E dish has non-stacked LNBFs and if that is the case, no harm in calling Starchoice and asking for a re-hit, since you switched from a stacked lnbf to non-stacked. From what I gathered from this forum, when you do this, make sure that you are on channel 299 when you make this call.
Good luck and post your results/solution for this 'unique' problem.