JBL Control 28 repair


2008-02-09 7:03 am
hi- i am stuck trying to figure out what is wrong with a pair of JBL control 28's and would appreciate some help.

i took the back assembly out, and the lamps look fine. then i by-passed the cross-overs and connected live cables to the cables inside the speaker that attach to first the woofer, then the tweeter, but got no sound from the speaker, nothing at all.

the speakers were given to me dead and i'd like to revive them if it is practical... any ideas?

the other question, the grill is tight into the front of the speaker: is a special tool necessary to pop it out? i started to pull at the grill with needle nose pliers under the logo badge area, but it began to slightly warp, so i stopped before damaging it.




diyAudio Moderator Emeritus
2002-04-03 7:15 pm
Rotherham, England
I have the crossover schematics somewhere I think, I'll try to dig them out for you, but it sounds like the tweeter is blown or damaged. With the C28 tweets, the magnet is only glued on the back of the motor, and rough handling can cause it to move and lock the VC assembly up. However, they are easily available as spares, any JBL dealer should be able to supply one for you.

The grilles are a real pain as they are held in with some incredibly sticky mastic. I use a steel pin from a pop rivet that will just fit in the grille holes, held in a pair of pliers, and work around the outside slowly. It can take a while.
we use control 30 in church and we first hooke them up I blew 2 tweeters due to overload, I now have a limiter on them. But if you take the label off there is a phillips screw remove it and then use a flat head and pry the grills from the edges where it meets the enclosure. I believe there is a gasket that holds the grill in place.