hi Adam . Please post a few pictures with it. Great that you were able to do a little reflow on it, it usually helps – also with getting rid of any humidity buildup.

Now, regarding de ESP04, you should be able to find it online and it is perfectly fine to swap it.

You will need to install a firmware on the new ESP module, than flash the uRADMonitor unit, separately. It is not hard to do.

Directly flashing the new uRADMonitor firmware now will not solve your problem, since the 3 beeps indicates the unit is operational, but cannot properly communicate with the ESP04. We need to start there. Happy to assist you further.