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View Full Version : 4312 & 4312A crossover/dividing network caps



groomlakearea51
10-06-2010, 09:45 AM
Please bear with me I am new to this Forum. I have a pair of 4312's (my original 1984's) and a pair of 4312A's (I'm second owner). Both pairs work very well, no "issues", etc. However, I understand that over time the caps in the crossovers may need to be replaced. Given that they are not "oil" caps, I may be incorrect, and if that is not the case, great. Otherwise, any advice, including the best method for accessing and removing the crossovers would be most appreciated. In addition, any recommendations for types of caps (Sonicaps? Auri's, etc.?).
Thanks for any assistance.

sperkerchef
10-06-2010, 12:28 PM
I'm the guy on ebay with the 4312s you asked a question about this morning. I'm willing to sell them outside of ebay if you're interested. If you want to give me a call that would be great.

richluvsound
10-06-2010, 12:31 PM
there is a upgraded network on here somewhere !


uF

groomlakearea51
10-07-2010, 05:18 AM
there is a upgraded network on here somewhere !


uF

I have tried the search function, however with no success for 4312 network upgrade or network upgrade. I may be doing it incorrectly, but wil learn...http://www.audioheritage.org/vbulletin/images/icons/icon6.png

If someone can remember the thread, that would be most helpful.

Thanks for any assistance

groomlakearea51
10-07-2010, 09:18 AM
I have tried the search function, however with no success for 4312 network upgrade or network upgrade. I may be doing it incorrectly, but wil learn...http://www.audioheritage.org/vbulletin/images/icons/icon6.png

If someone can remember the thread, that would be most helpful.

Thanks for any assistance

Continuing the "search" function, I came across a thread that discusses changing electrolytic caps that are +20 years old. See: #27096 "Is-there-any-benefit-in-replacing-electrolytic-capacitors-with-PP"

This would seem to apply to the 4312's (8uF, .01uF, 3uF and .01uF).

Anyone advise?

Given that the L-pad controls work fine, the only issue would be to remove the crossovers. In order to disconnect the L-pad wires, I assume they can be cut, and reconnected after re-capping the x-overs?

Anybody done that?

Sorry to be a pest, but I want to make sure the 4312's will last another 30 years until I get so old and tired that I have to give them to my children.....:crying:

richluvsound
10-07-2010, 05:05 PM
The screws holding the lpads are behind the decal..... the decal can be remove very carefully with thin
putty knife and a blow dryer .

Then with nail polish remover clean the old adhesive from the decal and reapply with contact cement or good double sided tape

I would replace the caps and deox all of the contacts . I'll hunt around for the link regarding the network ..

Rich


found it ... L 100 is the same ,but the domestic version http://www.troelsgravesen.dk/JBL_L100.htm#The%20Crossover

macaroonie
10-07-2010, 05:59 PM
If you are ambitious this is worth a read

http://www.troelsgravesen.dk/JBL_L100.htm

groomlakearea51
10-09-2010, 05:54 AM
Greatly appreciated; I hopefully will have a spare pair of the crossovers with which to "practice" in a week or two if all goes according to "plan".
The prospect of "lifting" that metal plate gives me great concern as "Murphy's Law" usually prevails in my case. The 4312's are mint; truly mint to the point that I still have the original boxes and end caps, foam pieces, green plastic bags, tech brochures, warranty cards, and the "tag on a string". I am very, very leery about possibly damaging them in any way; likely as not I will simply do the 4312A's, which have a few minor cosmetic issues, including a scratch on one of the plates.

Thanks again and I will carefully review the suggested thread.http://www.audioheritage.org/vbulletin/images/icons/icon14.gif

groomlakearea51
10-11-2010, 11:48 AM
Continuing the search for subject discussion and pictures.... I ran across this thread dating to 2007, but extremely interesting; part numbers, photos, etc.

http://www.audiokarma.org/forums/showthread.php?t=106180

While specifically addressing the 4311, it certainly applies to the 4312's as well.

:)