Can a 2405 test O.K. with an Ohm meter but still be bad? I'm not getting any sound from my 2405's
Can a 2405 test O.K. with an Ohm meter but still be bad? I'm not getting any sound from my 2405's
Let me suggest the obvious: Have you checked the L-pad on the crossover, or swapped the 2405 from one cabinet to the other?Originally Posted by quindecima
". . . as you have no doubt noticed, no one told the 4345 that it can't work correctly so it does anyway."—Greg Timbers
After I posted that thought immediately came to me. Something is haywire because both are not working and the L pad adjustment is not effective.
If you can remove it from cabinet and test directly. I had similar issue. It was fixed after I re flowed all solder points on crossover. It was Jbl L65.
I checked the wiring on the L pad and the speaker to the Crossover and all is good. I checked all wiring connections for continuity, I have nothing and the drivers ohm out good. I haven't swapped them because there is nothing out of either.
What is the genesis of this event? Did they both stop working at the same time? Are you firing them up for the first time? Did you check the operation of your crossovers before installing them? Have you checked to see if you are getting signal at the driver terminals? Have tested the tweeters with another signal source? Has something untoward happened? Did your little brother have a party?
"Audio is filled with dangerous amateurs." --- Tim de Paravicini
If you have nothing out of each, then you must remove them from the speaker and test individually with known good signal. If you have it, hook up the driver to a low powered amp, turn down all bass and mid tone controls or put a capacitor in series with the driver (3 to 3.3uf) cap for an 8 ohm driver, 2uf for a 16 ohm driver. That will filter out all the frequencies below about 7000hz.
Then play a low level known music signal with some high frequency content like cymbals, female voice, etc. If you get music, then you know the problem is in the wiring or crossover. If not, then ohm out the drivers again out of the cabinet to confirm if they are ok or open (blown).
And yes, important to know if there was any incident with your system before the drivers stopped working.
Assume nothing and troubleshoot.
When faced with another JBL find, Good mech986 says
, JBL Fan mech986 says
If it is 4333 or system with bi amp switch on back under terminals you can work that knob back and forth to clean it. The knob you use a screwdriver to switch from internal to external crossover. Work it back and forth about 20 times. That will clean pot.
I pulled a LE-5 from my L100's and replaced a 2405, no joy. I took one of the 2405 drivers and hooked it up in the LE-5 spot, turned it up until I got sound from it and re-ohmed them they are good and the silver seals are still unbroken. I rechecked ALL wiring and continuity between ALL connections, checked to make sure ALL connections were correct and then rechecked them ALL again. I am starting to think my hearing is so bad I can't hear any UHF.
Quin, I've not been following your posts in the recent past - what type of speaker and crossover is in question, and what mods have been done to it? If the ohm'ed drivers measure ok, then its the crossover. Can you provide the schematic and pictures of your crossover?
If there is a series element like a resistor or cap in front of the 2405, then one of them is open. Either that, or if there is an element like a resistor, inductor, cap or L-pad across both terminals, they could be shorted.
'
When faced with another JBL find, Good mech986 says
I'm looking for a short somewhere but in both speakers and the same driver? My head is hurting thinking about it. I'm close to pulling a crossover out and giving it a close look.
As I said before, assume nothing and troubleshoot, as you have been. The mystery of the no sound tweeters!
Reminds me of the Sherlock Holmes quote:
When you have eliminated all which is impossible, then whatever remains, however improbable, must be the truth.
When faced with another JBL find, Good mech986 says
That's what I would do next.
Just before I shipped them they had passed all voltage drive tests so it will be very interesting to find out why both UHF circuits have failed.
O.K. 4313B, That's the next move, I have to work today (unfortunately) but when I get home I will take one out and put it on my bench and carefully see if I can see anything. I peered all over it while it is mounted but I need to get it out to get a good look.
I'll try to get you another pair of networks by the end of May.
And that concludes my days on this forum.
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