JBL 4430 - What Damage ?????

[Harry]

Looking for help trouble shooting........I use 2 Adcom GFA 565 300 w mono amps with these speakers.I was having a problem with one amp and apparently had it repaired(loose connection in the Power Supply) but when I got it back and hooked up it and switched it on...it made a bang as though a 357 magnum was fired in front of me.Sounded real bad,not to mention the fright I got.Anyway now there is no bass,some crackling sounds emenating from below but that electrical charge must have fried something.
Any help would be really appreciated.....Thanks in Advance....
Speakers bought new in 1989.

Cheers Harry.

[johnaec]

Have you swapped amps to determine if it's the speaker or the amp that's bad?

John

[Harry]

Hello John,one amp is definately ill - gotta go back to repair shop.The speaker is pretty sick as well.Yes the good amp is fine and one speaker is fine.What assistance I'm looking for is to determine if the Driver is kaput,Network kaput etc..

Cheers Harry

[John]

Wow If that happened to me I would be pissed off!!! Have you used this repair shop before???

[johnaec]

I assume this means you've tried the good amp on the "bad" speaker and there's no low frequency output?

If so, I'd pull the questionable 15" out and check the resistance across the terminals. A short or open circuit will be a dead giveaway as to the speaker's health. Does the cone move freely in and out, or is it frozen in place?

If the speaker resistance and movement checks out, (I imagine between 6 and 8 ohms resistance), I'd next look at the crossover components.

John

[jandregg]

I would not try the bad amp on the other speaker. That could lead to two blown speakers. Use a meter first.

John

[scott fitlin]

I would not try the bad amp on the other speaker. That could lead to two blown speakers. Use a meter first.

John

This is correct. Whatever the problem is, your repaired amp blew up upon turn on, and took your speaker with it! DO NOT put it on your other speaker!

["Duke" Spinner]

i hope the repair "tech" soon hears of your displeasure ....

[johnaec]

I would not try the bad amp on the other speaker. That could lead to two blown speakers. Use a meter first.

I was thinking more of the good amp on the "bad" speaker, but of course, that could lead to problems too, especially if the speaker coil is shorted! Definitely check resistance first. If it checks OK and the cone isn't frozen, I'd put it in the "good" cabinet to check it with the known good crossover and amp, and go from there.

John

[Mr. Widget]

When I first saw John's post I was concerned about blowing the second speaker too, but obviously what he meant was take the known good amp and apply it to the known bad speaker, and see what results. If the results indicate the lack of bass and "some crackling sounds" we know the speaker is damaged. Next, take the "bad" woofer and place it in the good cabinet hooked up to the "good" amp. If it plays correctly, we know the damage was to the network, if it continues to lack bass etc. we know the woofer is damaged. Next take the good woofer and place it in the damaged speaker. If it plays normally, we know that network is good, if it doesn't we know the network is damaged.

This should be pretty obvious, but if you haven't already done so, it will be revealing.

Widget

[Mr. Widget]

There's John now... I missed him by a minute...

[Harry]

The speaker is not frozen and moves freely will do the swaps tomorrow and get back to you, could not check resistance( no meter - will get tomorrow).Thank You all for your help so far .............Harry

[Harry]

Hello,doing the thanksgiving turkey eating at the in-laws today soooooo,do the swaps tomorrow,Just wanted to keep you in the know....

Cheers Harry

[Harry]

Morning All - well the damage is to the woofer it is not working.Can it be repaired or is a replacement 2235 purchase required????? Waiting for Guidiance..
Cheers Harry

[scott fitlin]

Good morning, Harry. Your 2235 can be reconed. Do you have a competent JBL authorized repair where you are?

Are you certain that whatever happened when your amp blew, it didnt fry anything in the crossover network as well? It did take out the woofer, it could have damaged something else as well.

If you do have an authorized JBL repair on Cape Breton Island, I might opt to let them look at the entire speaker. I know what I`m suggesting is a major PITA, but you need to check the xover network in the speaker that got damaged as well.

BTW, I went and googled Cape Breton Island, was looking at Baddeck, very nice place!