I've come back to my Fisher Delta after a break, and still can't get it operational. The problem is the same as before: I can connect with the web control and send commands (eg home all... which it does) but no responses appear to come back. Sending a G Code which should elicit a particular response doesn't get anything, and pressing down on the bed as described in the EMaker instructions doesn't make '1000' appear in the Z probe sensors box.
I previously experimented with using the latest firmware and sd card files from dc42 fork (1.15 / 1.12) but this made things worse and couldn't connect at all. I have reinstated the original Emaker software/firmware, and everything is from the same Fisher Master Zip off Git-hub and all appears to be v 1.11.
While I can connect, all is clearly not quite right. I press the connect button, and it says 'connecting', but doesn't, but after pressing twice more, it does finally connect. As suggested by dc42 I tried ctrl-shift-j in Chrome and it comes up with a load of syntax errors. I have attached a screen shot of this.
After a titanic process of trial and error, it looks like my computer was somehow corrupting the files on the SD card. Maybe the card reader? I tried transferring the the files onto the SD card with a different computer and hey presto...everything works! A minor problem with the bed probe switches not closing, now resolved I think, and who knows we could be printing soon. Thanks dc42.