PACE DS810XE mosaic pictures on SD TV

[5004497]

Hello,

I recently bought a PACE DS810XE satellite box for use with a new Full HD TV (Sony Bravia KDL-32W4000). Firmware has been upgraded to version 1.0.35.
I encountered odd artifacts with SD TV channels (mosaic or bloc apparition on pictures). On the contrary HD channels give an extremely good and sharp picture without artifact! The PACE is connected through Disecq switch to 3x twin universal LNB (pointing to Hotbird 13E, Astra 19E and Astra 28E).
A second terminal (Humax HDCi 2000) doesn't encounter such problems (while using the second connection of the twin LNB).
I thought it could be a signal strengh issue (Humax indicates signal strengh 43% and quality 97% for both Astra and Hotbird satellites). But how explaining the good receiving of Humax Sat receiver (both SD and HD channels) and problems with PACE DS810XE (only in SD) ? Indeed, while setting up DS810XE for LNB, bargraphes are fully green as installation validation. Did someboby get this issue ? Thanks to your help ! Regards.