One group calls for 'fan' level knowledge of a TV series. Another calls for detailed knowledge of the output of one manufacturer. Whether either of these count as general knowledge is open to question. I solved it, but didn't feel it was very satisfying.

IR,,quite a lot of grids are like that,,pop knowledge or sports sometimes.

IR i didn't know either and solved it (though didn't get the connections for the two). Often you can use logic or feeling for language to figure out a group.

I said 'psychologists' - it said I was incorrect... Ho hum...

Wasn't impressed by this one - very specialist knowledge of a particular TV show needed and also products not sold on my continent.