Had this problem and took me a couple of days but I found the issue, well with mine I did so hopefully it may help more.
Where the positive lead comes out of the base and soldered onto the board there was a small, and I do mean small splash of solder that touched the negative path on the circuit. This is not just quite dangerous as it is a unprotected short on the PCB but it confuses the resistance reader due to the two polarities already making contact before the 510 connector. You may have it on a different location but if you take it apart and look at where the positive is soldered on check there isn't any solder, juice or dirt that could be giving a false reading as where it doesn't recognise the coil it is actually already reading a resistance from somewhere else that is a lot higher than it is programmed to do so won't recognise the slight change a coil will make.
Hope this helps as it's my second one after the first getting the screen of death so didn't want to give up on what is a pretty decent mod.
