I know this is old, but I also wanted to give kudos to c036416.
I just had a first gen WH51 fail, LEDs still light as normal, but no RF transmission . I went through all the normal steps, but I'm not seeing anything on my SDR either.
I pretty much followed the disassembly posted, however, of course, pretty much managed to destroy the case in the process. So, my advice only attempt as a last step, and I am bit ham handed.
After having gained access to the circuit board, cleaning it , powering it up on its own, well, no change. I'm not terribly upset by this as I have 7 now instead of 8. Also 4 more on order.
Some other notes:
In my case there was obvious water ingress in the battery compartment, also one of the top screws under the cap had rust on it. If there was a design improvement to be made, in my eyes it would be to add an O-ring , under the battery cap. There is not enough space there now to add one