That model was available in various panel sizes (e.g. 26", 32", 37", 40").
From the service manual, the 40" adds a screen balancer (DS1) off the inverter board and there are different power supplies (GS boards) used, depending on size.
There only seems to be only one main type (B) board.
However, as described in section 3 (e.g. electrical circuit adjustments), there are different WXGA settings that configure each panel size.
That board should work, but more than likely will not be plug and play.
Have you tried to restore your main board setting, using the information in section 3?
Additionally, some board suppliers offer a free return policy.