Hi,
I'm far from being an expert on 1292, I've mine since few weeks... Anyway, I can tell you that it's a complete different shape than other 12xx.
First there is no "screen" by nature ! nor "focus" as it's an EM focus crt and all is control at the remote level.
The line you seen on top is the AKB (ABL ?) aka Automatic G2 control.... There is no direct easy way to change automatic G2... But this can be done, check in the user manual, last pages...
Seems you really experiment an issue under driving your Blue tube... Have you try a full reset to factory settings ??
I've heard about a "special" mod on the blue deriver on 1292, but don't have any details...
Anyway, even if the 1292 is not the brightest pj in the world, the result picture is amazing, trust me, you may want more lumens on paper, but at screen it's really stunning... if you keep a reasonable screen size (2.50m base in 16/9 in my case).
--Patrice