I got through spire relatively easy but i think i hit a bug. I am at the platform where the switch for the crystals is, after the harmonics puzzle. Pulled the switch, and examined the two chambers. The codes learned here are obvious, after entering them everything lights up brighter than the sun and then..... nothing, i read walkthroughs and watch a video but cannot find a fault in my ways. The interwebz does not yield much info either, no info this bug so far.

Short summary of my actions;
Exit chair, flip switch, play with electrical device, read journal, look at chambers and baskets, return to chair, enter the harmonics.

I been at this puzzle for well over 3 hours in total now, re-discovered the entire age two times in the hope i missed a clue; nothing. Seems like i have to start over new?
Not really a happy thought.... Not that the myst games are time consuming once you know the solution to all the puzzles but still

Yes that's nasty part, the puzzle you just solved isn't quite finished after all. I can't remember the exact solution anymore, but here's what I recall.

*SPOILER*

After you solve the chair puzzle you can exit at the lowest level. There you'll find a switch and a basket. You need to set the switch correctly, and the basket too. This is one of those puzzle where you have to "fail" in order to win. From the chair you you used to get all the way down you can do something new after setting the newlu found switch correctly. You can send pieces of ore of some kind down to the basket. As you have learned one of those is very explosive. Send one down to the basket, but send in down so that it misses the basket. It will explode and reveal an elevator.

Sorry if I'n too vague. Don't know if this is all correct, it's been a while. It's something along these lines.

Thanks for the reply. I found a older save which i thought i didn't have and completed the age.
Like i said i entered the code and nothing happened, what i encountered was a bug indeed. Doing the exact same things in an older save led to an explosive event.