Question Help with no sound from JBL 3677

fallinlight

Well-known Member
Dear all,

Today I became a proud new owner of a used LCR of JBL 3677. Just having heard a couple minutes of the FL speaker, these speakers are phenomenal and sound better un-eq'd, than my XTZ M6 sound eq'd.

Well, to my great dismay and upset, my FR is not working. I feel absolutely gutted and all drained now. I have messaged the seller an am awaiting a response.

Problem: I noticed the terminals are loose: the nuts are not flush to the white plastic rings. And the nut on the inside is not flush with inside/ back of panel - so, they have some wiggle. Opened the panel, and fiddled, nothing. Checked wires quickly on my XTZ S2 terminals, working. Put 3677 panel back unscrewed and touched wires down on terminals, there was sound for a few seconds. And released and touched again and sound. Then tried again, no sound. And no sound since, having tried for quite a while. Everything looks secure - APART from the terminals themselves - but does this matter? I can't secure them, my pliers is too large and I can't hold the long threaded bit in place to spin the nut.

I will try have a look to see if I can find a wrench around house, but don't think I have one right size. Again, is it just a case of the terminals needing securing? As I do not see how this will help, if that is all it is - PLEASE, that would be great.

Does anyone know what I could try. Does anything look amiss here? To my eye, nothing looks loose apart from the terminals:


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Kind thanks all and my well wishes,

fallinlight
 
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fallinlight

Well-known Member
Just off phone with Mark at Soundtech, nice guy. Probably spoken to him in past actually, if they deal with projectors, too. His voice sounds similar. They wouldn't repair it he said.. hmm.

It's too confusing for me but he said try an auto-ranging multimeter at terminal and HF and LF wires to see if they are good. If so, then issue is at the crossover. Issue is likely EARLY on he thinks, at the LF and or HF CROSSOVER. But would need to take apart/ take woofer out etc. Could be broken or loose component on panel circuit board but very hard to tell by looking if untrained.

His best advice was multimeter, but really to find a repair man/ service.

Sigh. Again, it's all beyond me. He said worth securing terminals, but did not get a yes/ no from Mark, if that would help. I will try that shortly.

UPDATE: I managed to fix the speaker shortly after. Please see my last post.
 
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fallinlight

Well-known Member
@dobrykamil, @Gasp3621, put me on to you, do you have any ideas on my issue, please? @Smurfin, Saul said you had a similar issue with your 3677?
 

fallinlight

Well-known Member
Does anyone know what size wrench should fit the nuts on these terminals? I need to at least try fastening them!

Kind thanks
 

dobrykamil

Active Member
Hi
Yon to check conductivity between speaker termianls and the soldering points where the audio signal comes in to the crossover board.
 

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fallinlight

Well-known Member
Kind thanks, I will order a multimeter from Amazon now then, and try this tomorrow.
 
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fallinlight

Well-known Member
Mark at Soundtech said I touch one end of the multimeter to the terminal and the other to the bare wire from the HF/ LW wires - do I have this correct? I will take a new photo soon and circle the points I think are correct, or if you can circle them, please then that would be great.
 

fallinlight

Well-known Member
Issue is likely EARLY on he thinks, at the LW and or HF DRIVER parts,
CORRECTION: Just spoke with Mark once more to clarify - as Jag can sell me a brand new crossover - and he said if issue is early on, it will likely NOT be the drivers, but the crossover.
 

fallinlight

Well-known Member
Just received my multimeter and tried phoning Soundtech but Mark is not in today. I was hoping he could run me through how to use it. Not sure if I need to re-connect the driver(s) to the crossover, too.

Can anyone here please help? For start I am not sure which sockets to plug the red and black leads into. There are 3, labelled, 10A, COM and V,,, Hz. I think I would just leave the meter on the default setting - it says "AUTO" when I turn it on. And then do I touch one tip of the lead to a terminal and the other to one of the +IN/ -IN solder joints? Does it matter which terminal I touch the tip onto?

Kind thanks
 

fallinlight

Well-known Member
OK, I just watched this video which seems to explain the process for testing continuity very well, which I assume is the same as conductivity, which is what I need to test:


So, I assume I can test for continuity with the crossover detached and not connected to the drivers.

My only question now, is do I touch one end of the lead to the actual solder blob/ joint, or to the black/ green wire that goes into the binding post? And I understand I touch the other end to the binding post itself?
 

fallinlight

Well-known Member
As per @dobrykamil's above post, I will go by that. So, touch one end to a solder joint/ point, and the other end to a speaker terminal - the gold binding post. This makes sense to me.
 

fallinlight

Well-known Member
Right, so!

It seems I had to touch the black lead to the terminal, as the other way around did not seem to do anything. Results:

- I get a beep for the black -IN, and 2 'click/ tick' sounds for the +IN red.
- For the -IN test, I get various, different readings on the meter screen, but not sure if that is to be concerned about or how to read them.

Conclusion: dry solder joint or other issue with the +IN red wire?
 

fallinlight

Well-known Member
To add, for the working -IN, it sometimes takes a while to get a beep, I have to keep trying the tip on the solder joint until it beeps. It is not immediate and does not beep every time on contact. Is this also an issue? Could this joint be going dry? And or the wire to the terminal is loose? Or, could it be just the multimeter acting up?

EDIT: it seems it does not matter which way around the black and red leads are/ touch. I was able to eventually get the beep either way.

However, I did get sound momentarily on the first night, so could it instead be the wire is loose to the joint and or terminal? I have not been able to get sound again after fiddling/ moving it around.

UPDATE: I checked again, and either _IN and +IN solder joint appear to be wiggling. And from as best as I can see, the red wire goes securely into the back end of the joint/ panel and into the back of the binding post.
 
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fallinlight

Well-known Member
UPDATE:

I fixed my dead speaker. Anyone needing to do the same possible fix, can find how I accomplished it here; I wrote a guide for refitting the crossover and woofer:

 

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