I never heard of a non CRT RPTV (or any other) that was that dark. Is this in a bright room in daytime or a light controlled room?
When the lamp dies, it dies, there is no middle ground. Have you 'tweaked' the set yet?
BTW, welcome to the forums (and your girlfriend did the right thing).
Free, abundant OTA television separates this country from many others. ATSC1 has only been in force since 2009. The wireless industry has enough spectrum. Enough of 'planned obsolesce'.