What's the scoop on the old Jensen Corp "Advent" speaker by H. Kloss?

The original Advent was not made by Jensen. That switch was used to boost the tweeter output. I owned the Advent many moons ago and it was outstanding for that era! It is listed as one of the most significant speakers ever produced!
https://www.audioholics.com/loudspeaker-design/most-influential-speakers

More info!

http://www.theabsolutesound.com/articles/the-12-most-significant-loudspeakers-of-all-time/

And more!
https://www.stereophile.com/standloudspeakers/171advent/index.html

Harry Pearson used stacked Advents (2pairs) and LOVED them.  I would restore them, not gut them. 

Agree with stereo5, restore them, and that done properly should sound much better than just reusing the cabinets. Also, restoring will increase their value.

Thanks fall for the links and the advice.  I have not been able to find any of the technical data on the original exept a 2800Hrz crossover.  I do not know what this switch on the back is intended to do.  I am not the best one for this task but would consider a full retoration if I knew what I was looking at.  Thanks again and, , Any help there?

Are you sure those are original Advents? The xover is 1000hz and the switch is for the tweeter! Here are the specs!
https://www.stereophile.com/content/advent-loudspeaker-specifications

Yes, these are the original real item.  I have a note to myself I read somewhere along the line that gave the 2800 Hrz number.  I have not been able to confirm this or any other.  
I tried the site yogiboy sent (thank you) but the site is temporarily down and I can't get in.  I get that the switch is for the tweeter but I can't find any data on what this switch actually does or what capacitors are probably used and to what end?  This switch unit needs to be rebuilt along with reconditioning the crossover.  
I will contine to check this site to see if it comes back up and would welcome any other access to this data anyone may have.  
Thanks again, you all are great!

The lower crossover point (1000hz) was for the Original Advent. The Advent with the higher crossover point was for the New Advent Loudspeaker which I believe came around approx. 1975 or 1976. The physical difference between the two is the original had all squared off corners. The front of the New Advent had rounded corners and front edges. I also believe they started using ferro-fluid "fried egg" orange tweets in the new version. The reason for upping the x-over point in the New was to stop blowing out the tweeters. People who had the old version were burning out tweeters with excessive power input and usually with rock music of the time. Advent addressed the problem with the higher crossover point and ferro-fluid (for cooling of the magnetic gap in the tweeter). This in turn gave the tweeter extended life but unfortunately narrowed the high frequency radiation patterns which many people found fault with. I have tried to be as accurate as possible about this, but it was from an article I read many, many years ago. I apologize for any inaccuracies.

The more I think about it I believe the crossover point for the Original Advent was 900hz.

I owned and like the Advent speakers but speakers age. I have refurbished speakers but do not recommend it. I found it more economical to replace the individual speakers.


Scott

I was able to open the site yogiboy sent and that helps.  The set I have is stamped "Jan 12, 1977".   I did learn that the switch acts like an entenuator or L-pad with 3 distinct settings at 3 dB steps.  A whole page pasted to the backs of the speakers explains that this was to accomodate the quality differences in the records themselves and amounted to 'turning up the treble' in playback.  This was very effective then.  Most amplifiers offer wider shifts than 3 B.  The new analogue Marantz PM8600 has a fully integrated low-mid-high tone controls with a range of 15B up and down from flat.  
Just thinking but this seems like something that is not worth the effort to replicate if the intention is to listen to these speakers.  I have not opned them but I now picture 3 resistors plugged into this switch that would be cheap and easy to replace.  I will see soon.
The bass drivers were taken out long ago and now have Tandy/Radio Shack woofers so there are none to 'refurbish'.  I have heard some very nice replacement speakers that could easily fit the 1000Hrz ( or so)  crossover mark.
These strange tweeeters in a cage perform very well but the sound and ability to perform are dated.  Even Advent moved to different tweeter models over the years.  I think I get what Scott69 suggests and that a new crossover package without the 'switch' and with any one of many great teeters would be great to hear.  
I appreciate the historical and nostalgic love of these olddies and don't want to desecrate a monument either.  Would my karma better served by passing these on to someone who would want to preserve them?  I did not expect to end up with an ethical problem!