Anthem AVM50 OSD

Hello everyone,

 I would like to start by saying that I love this site. The information provided has been very enlightening. Although I can't afford to buy brand new equipment I am at least able to afford older and gently used equipment.

 The question I do have is relating to the on screen display for an Anthem AVM 50 (it is not the V or V 3D version). Everything was working fine with the on screen display for both the configuration menu and information menu (volume etc). I purchased a new larger tv (65 inch UHD tv to replace a 32 inch 1080p tv) and the menus were visible for the first week or so. Now the menus are no longer showing. The configuration menu now shows a black screen and the information menu shows a box with horizontal lines (connected through HDMI as there is no component connections on the tv). The HDMI passthrough and up conversion to 1080p is still working and does a good job (ps2 video output looks pretty decent while connected through component and output to tv through hdmi on the AVM 50).

 I am able to access the configuration menu and can make changes but only viewable through the display on the unit itself. I have reset back to factory settings and still no change. I can't try the older tv as it no longer worked and was the reason for the replacement.

 Is there another way to reset the AVM 50 and restore the on screen display. I love the sound quality of this preamp/ processor and the lack of the OSD is not that big of a deal. I just don't like it when things don't work 100%. 

 Any thoughts would be greatly appreciated.
Kevin