Trying to save some Quantum Jrs

stinz

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I found a pair of very neglected Quantum Jrs, in need of a refoam, mid repair on one and emits in both speakers. Someone put foil over the fuses so I'm sure there will be other problems. One I found was the mid range pot is melted stuck so what replacement pot should be used?
 
This was recommended in another thread but I have not tried one. http://www.tedss.com/5905-201-9940/ Sometimes those pots can be cleaned and repaired, have you opened it up? Check Ebay for parts, someone is parting out a pair of Q3s right now but I think they want to sell all six EMITs. Good luck with this project, and keep us posted!
 
Well things are going ok right now, I have reformed the woofers and repaired the bad midrange with the help of a thread from here. I have some replacement emits on there way so the only thing left is to replace both the midrange pots. I have tested the crossovers and they work even with the frozen solid pots. Here are some picture of one of them I think they are beyond repair.
 

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Here are a few more pictures of after a little Howards restore a finish on the cabinets. One of the reasons I picked these up was they came with the Infinity metal stands pictured!
 

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those stands have always intrigued me for some reason.
i always assumed that they sat on a shelf type arrangement- like a square "C"

they look awesome.
there is a threaded insert of some sort in the cabinet that the stands screw into right?
 
No threaded insert, just 1 inch screws in the particle board to my surprise!
 
The stands look so cool BUT they are totally bouncy! The heavier the speaker the more they sag down. My Qbs make them bend pretty far, I bet those big Jr.s really don't point up much.
 
Well the EMITs showed up today so I was able to put the back together till I can find some replacement pots for the mids. They sound very nice, next project build some new fronts!
 

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If you are planning on making new baffles, mirror them!

+1 on that idea. I assume they were not mirrored in the first place simply to reduce manufacturing costs. If my Qb cabinets were not in such good shape, I'd re-build them and mirror the tweets.

Loved elnaldos' build thread. A LOT of work to recreate those metal stands. Glad I bought mine with the speakers back in 1978. I always wondered if the three drywall screws would be enough, but they have held up. They do sag a bit, though. And they will rattle and buzz if placed on a hard surfaced floor.
 
Well I finally have the homemade fronts done, not identical to the originals but close. Now if I could find some replacement pots for the mids everything would be great.
 

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or replace it with a 2.5ish ohm resistor...i usually have my pots set to flat which is halfway (on most)...i did this with my RSe's...
 
:thmbsp:

If you want to go a step further, the original frames come with a "dent" beside the tweeter, to help horizontal dispersion.
 
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