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setha2z
05-27-2008, 08:14 AM
I have a recently acquired "nice" pair of JBL L200B speakers with noisy crossover pots. I have exercised the pots well, to no avail. I suspect that the sound is affected, even when I find the quietest positions possible. How should I approach correcting this? Should I take the speakers apart and spray contact cleaner of some sort into the pots? Should the pots be replaced? I am technically naive compared to many of you, but want to do what I can to restore nominal performance to my speakers, hopefully without damaging something. Thanks for your consideration and help.

Mannermusic
05-29-2008, 07:27 AM
Howdy-

You can either clean 'em with Deoxit cleaner/lubricant/preservative or just do an R&R. In my experience, it is best to remove the tin covers and use the liquid Deoxit with brush directly to the wiper and coils. Wipe clean with a Q-tip. Get a piece of paper between the wipers and coil surfaces and wipe clean. Just did a pair from a 4313B, took about 2 hours but seem to work like new (so far). Can try spraying with the caps in place (if there are any openings in the covers) but difficult to get the stuff in there or wipe clean. Tends to make a mess. I'd say a temporary solution - haven't had much luck that way myself. To replace, you need a 16 ohm, 30 watt L-pad - can check www.parts-express.com - or other closer by. But, of course, need basic soldering skills. This stuff is old, takes continuous TLC! Good luck! :) Mike

setha2z
06-02-2008, 07:19 PM
http://www.partsexpress.com/pe/showdetl.cfm?Partnumber=260-261

Will this L-Pad work? I am having trouble finding the 30W item you specified.

Thanks,

Seth

Mannermusic
06-03-2008, 05:07 AM
http://www.jblproservice.com/parts.html

That's way more current capacity (100 watts) than you need. Looks like Parts Express has a limited offering on 16 ohm L-pads. I also see a 50 watt (260-254) listed that may work. However, all the JBL L-pads I've changed/cleaned use 1" shaft length and both those Parts Express offerings are 3/8" - I'd get in there and measure the original L-pads for both physical and electrical specs. The JBL part number listed on the schematic is 51594. See JBL pro service parts address above. Also, see the Technical Reference section at the bottom of the site intro page which has links to parts, schematics (consumer tech sheets). A ton of info! MM