L100 help

Hello all,
I am a new kid. I hope you can help with a L100 problem. I have three sets of L100's, two work fine, but the third, I bought at an estate sale, are gettinn no sound from both the tweeters and mid range. It sounds like everything is getting shoved throught the woofers. These appear to be the early issue with the vertical placement of drivers. The cabinets are gorgeous, which makes me believe someone refinished the cabinets, and did not install the drivers wiring correctly, or there is a crossover problem. I hope someone can help me out here, as I live in a very small town with no electronics service shops within 50 miles.

Why three sets? I bought my first pair of L100's in 1972, and was knocked out by that sound. In 2002 I went searching for the same stereo system I had back then, and the L100's I had in my youth. Long story short, now I have three vintage Pioneer silver systems with those great Jbl's cranking away.

It is just something about the sound from them that hits me ears perfectly.

Thanks,

Donald Bowman

http://manuals.harman.com/JBL/HOM/Te...NTURY%20ts.pdf

The crossover network on these speakers is very simple, and there is no filtering for the woofer, it receives full range audio. The most likely cause for your problem is bad L-pads on the tweeter and midrange.

WOW, talk about fast. You guys are great. Now can you tell me how do I check the L pads, and are these replaceable, and are they available to replace?

Thanks again,

DOnald Bowman

Quote:

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Originally Posted by Mrmonster11

It is just something about the sound from them that hits me ears perfectly.

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You are a lucky man, since you have three pair...

Quote:

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Originally Posted by boputnam

You are a lucky man, since you have three pair...

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Of ears?! :blink:

Sorry... post count was 7549 and that's an ugly number.

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Originally Posted by Giskard

Of ears?! :blink:

Sorry... post count was 7549 and that's an ugly number.

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:rotfl:

Hi.

Since you have 3 pairs, why don't try the mid and hi speakers of the working ones in the ones who does not work. If they work there, the ones in the 3rd set are probably blown.

Just a thought.

Congrats on having three sets of something you love. I have two pairs of original in line L100s myself.

Rolf's given good advice, and I'll add a caveat. The tweeters will be hard to remove, so just swap a couple of midrange speakers to see what happens. If the mids from your nonworking set suddenly play when installed in a working pair, or if the mids from a working pair suddenly do not work when installed on a nonworking pair, then you know the problem is internal.

If the mids from the nonworking pair do not work when put in a known good box, then the speakers are the problem and either need to be diagnosed or replaced.

Hello,
I was able to swap out the mid range speakers to the good speakers, and the mids are working. So that puts me back to the crossovers. Is there a way to check these?

Also, I went to pull the Woofers, and one of them is odd, the retaining screw spin freely, not tight or back out, just spin. the woofer does not move out of the cabinet. I am beginning to think some one caulked it in, any ideas on getting the woofer out without damage to it or the cabinet?

Thanks,
Don

Hello again,
well I got he woofer out. the guy before me used those claw based nuts, and they were just spinning around. I had to pry up each corner with pressure and then back off the screws.
I am now faced with a crossover I can not identify. I haven not pulled them out yet, but the crossovers are odd, as there is one small crossover inside a cylinder about two inches in diameter and the two pads. Not at all like the crossovers with the two battery shaped crossovers glued the the panel.

Any ideas?

Thanks,
Don

Quote:

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Originally Posted by Mrmonster11

Hello again,
well I got he woofer out. the guy before me used those claw based nuts

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I think those are original. Been on both my pairs.

That's the early version of the L100 crossover. Nothing unusual about it. It shouldn't make any difference for the task of changing the L-pads.

Well, after looking at what is going on in my L100, I am beginiining to think this is a wiring problem more than anything, as what I can see without pulling the crossovers out, it does not look like the wiring diagram.
I hate to have to peel of the label to get to the two screws that hold the crossover in, any suggestions?

Also the tweeters are marked LE20-1 are these original to the straight line version, are they better or worse than the 25? Iknow how the 25 sounds, but since I hae not had this pair runnin yet I can not tell.
Thanks,
Don

The factory used those "T-nuts."

Look again at the tech sheet. LE20-1 is correct.

They sound about the same as the later LE25.

Use a heat gun or hair driver to soften the glue and carefully peel the label without bending it. Slide a utility knife blade or several under to separate it....