Replaced logic board, no boot, just fan spinning and sleep light on

So my trusty A1342 had one of its RAM slots die unexpectedly, and I ordered a refurbished logic board online.

It originally came with the 2.26Ghz board and I went for the 2.4Ghz, just to eke out a little bit more performance out of it.

However, while the replacement board seems to be in top shape (nothing bent/broken, all connectors are snug etc), after installing it into my Macbook it appears to be dead.

The magsafe light indicates charging. Pressing the power button spins up the fan, and the sleep light turns on, but that's it - no beeps, no error codes, no light flashing, no DVD spin up noise.

It just stands there, spinning its fans. Removing the RAM is the same (no beeps), so I'm guessing the board is fried, right?

Is there else I should have swapped when switching logic boards? Does a move from the 2.26ghz board to the 2.4ghz pose problems?

Thanks in advance