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Madien3388
02-10-2009, 10:26 AM
Hi,
I recently replaced the binding posts of my 4344 and discovered that one capacitor has a strange aspect when dismounting the filters.

I have been told that all capacitors of this JBL monitor were in polypropylen, not chimical ones. Only chimical capacitors flow when they are dead, so it shall not be the capacitor but the glue used to stick the capacitors on the filter?

If anyone would be able to help me on this, it would be great. To know if it is only the glue which has flown under the capacitor or if it is the capacitor which is dead. I'm started to worry ...

:help:

Many thanks in advance !

Chas
02-10-2009, 10:41 AM
Bonjour Madien 3388. Actually, I believe the capacitors were Mylar in the 4344/4345 networks. When I looked your pictures at first, I thought it was simply the hot glue used to secure the cap running down the board. I have never seen anything like this oozing from this type of capacitor construction. the ooze is a different colour than the glue.

You could remove it and measure it. Or better yet, simply replace it.

Madien3388
02-10-2009, 01:17 PM
Bonjour Madien 3388. Actually, I believe the capacitors were Mylar in the 4344/4345 networks. When I looked your pictures at first, I thought it was simply the hot glue used to secure the cap running down the board. I have never seen anything like this oozing from this type of capacitor construction. the ooze is a different colour than the glue.

You could remove it and measure it. Or better yet, simply replace it.

Thank you Chas! I am quite lost as polypropylen capacitor doesn't do that when they are dead.
The liquid is very solid, like the glue under the capacitors. Liquid from chimical capacitors is not so solid, more sticky.

I am quite afraid to remove it as it seems that the speaker works great... but it bothers me much !

How could I know the type of the capacitors ? Polypropylen or not ?

Where can I find the 4344 schematics to find out the function of this capacitor (is it used for the 2235, 2122, 2421,2405 ?)

Many thanks
Damien

jcrobso
02-10-2009, 01:46 PM
http://www.mcmelectronics.com/product/50-4566

Ian Mackenzie
02-10-2009, 04:52 PM
Looks like Alien goop!!

Its a shunt capacitor in the horn filter.

I would be inclined to leave it alone unless the substance is effective / contaminating other components.:)

Ian

mech986
02-10-2009, 05:02 PM
3144 network, charge coupled version.

http://www.audioheritage.org/vbulletin/showpost.php?p=175125&postcount=5

Madien3388
02-11-2009, 12:56 AM
Thank you so much for your help, I really appreciate that !

What is the function of a shunt capacitor ?

If the capacitor was in fact damage and not working normaly, what kind of impact could I notice on the speakers response (I have a measurement device which can measure the sound produced by the speakers)

And sorry but what is the meaning of "goop" :o: ?

Thanks JBL fans :)

Ian Mackenzie
02-11-2009, 04:27 AM
Thank you so much for your help, I really appreciate that !

What is the function of a shunt capacitor ?

If the capacitor was in fact damage and not working normaly, what kind of impact could I notice on the speakers response (I have a measurement device which can measure the sound produced by the speakers)

And sorry but what is the meaning of "goop" :o: ?

Thanks JBL fans :)

Goop is Alien snot!

Do a search on 3145 crossover schematic

Compare one box to the other.

If both are gone find replacement for both (do both anyway), perhaps a mid price part from Parts Express or a Kimber Cap from Sonic Craft and replace the same part in both crossovers

I put together a whole thread on this a while ago

http://www.audioheritage.org/vbulletin/showthread.php?t=13930&highlight=3145+crossover+pictorial

Upgrade/repair thread

http://www.audioheritage.org/vbulletin/showthread.php?p=178769#post178769

That is will cost to a slab (of Victoria Bitter)!!

Chas
02-11-2009, 05:35 AM
Hmm...I just might have all the JBL OEM capacitors I changed out of my 3145/4345 networks somewhere at home. :D

Madien3388
02-11-2009, 05:36 AM
Thanks Ian ! I have already checked both filters. Only one has this goop under the capacitor. All other capacitors seem fine.

Is it possible that this goop comes from the capacitor itself? normally, polypropylene capacitors doesn't do that as they are made of metallic films. If the capacitors are really in polypropylene, it can not come from them, can't it ?

I take a lot of care of my vintage JBL speakers and want to keep them for a long time. I have already changed the binding posts for better ones; but I am very afraid to intervene on the filters. I do not want to do worse. What is the exact value or reference to use, and where to find the glue to stick the capacitor on the filter?

I have had a look on your links. It is very impressive. Is it possible to find such 4344 filters already tweaked ?

I really appreciate your help
Best regards from Paris
Damien

Ian Mackenzie
02-11-2009, 05:36 AM
Now them things are priceless.

Madien3388
02-11-2009, 05:44 AM
Link to capacitors adviced by Ian, if it can also help someone else

http://www.soniccraft.com/kimber_capacitors.htm
In my case, it would be this one if I am not wrong : 1.5µF /

3µF / 200VDC 0.70 x 1.68inches $11.94


I have also found this in Auricap: http://www.soniccraft.com/auricap.htm
3µF / 200VDC 0.90 x 1.00inches $19.44


But I am not an expert at all in filter components and tweak, so I do not know the differences between the 2 model.

mech986
02-11-2009, 01:02 PM
Assuming you are not the one and only original owner, do you know if any previous owner may have done some work inside the speaker? The residue that is sort of a yellow drip on the end of that capacitor looks suspiciously like yellow wood carpenter's glue (PVA glue).

If the crossover had been removed or worked on and the capacitor hit or moved, it may have come loose from the original semi-clear adhesive (possibly hot glue?). Maybe the original capacitor was blown and a new JBL cap (looks like it was sourced from a similar batch as the other large caps) was installed later with regular glue?

As far as I know (AFAIK), all JBL crossovers of that era used Mylar (polyester) film caps with small polypropylene bypass capacitors.

bart

mech986
02-11-2009, 01:06 PM
Original 3145 schematic, need to magnify the pdf to see well and some of the component values are difficult to read.

http://www.jblproservice.com/pdf/Network%20Schematics/3145%20Network.pdf

Madien3388
02-11-2009, 02:41 PM
That is very interesting Mech986. Thank you! I didn't notice that. Indeed it is a possibility. The capacitor seems a little longer than the one in the filter of the other speaker (I have attached a picture of it). So it may have been replaced, but it seems that an original Mexico capacitor was used.
What is strange is that the glue under all capacitors has the same colour, and the other capacitors don't seem to have been replaced.
It is quite a mystery.
I think I'm going to buy the spare capacitor, just in case and will wait a little before repacing it.

One question please: Can "Mylar (polyester) film caps with small polypropylene bypass" capacitors produce this liquid when they are dead, like chimical capacitors ?

Or, if it possible, I will find other crossover filters with "up to date" components...
What do you think ?

mech986
02-11-2009, 03:18 PM
One question please: Can "Mylar (polyester) film caps with small polypropylene bypass" capacitors produce this liquid when they are dead, like chimical capacitors ?

Or, if it possible, I will find other crossover filters with "up to date" components...
What do you think ?

Thanks for the kind words.

In my experience (IME), typical film/film-foil/metallized film capacitors will not leak or drip like this, assuming they have the typical end cap seals of epoxy. Much older JBL film caps were encased in a cardoard tube and wax impregnated. High heat from lots of signal current could theoretically heat the cap hot so the wax version may show signs of melting but I've never seen that.

The typical polyester epoxy closed caps are usually rated at 50 deg. C., 85 deg. C., and up to 125 deg. C operating temperature so I doubt the epoxy end caps or even the cap itself is the source of the mysterious drip material, at least for modern caps.

Regards,

Bart

upon yet another look at your original picture, it does appear that the large film cap and possibly the small 3.0uf film cap in question have an endcap material, and the endcap material on the 3.0uf unit looks damaged. Why is the question - excessive current? Heat from a soldering job? Get us a pic of the other end of the 3.0 uf cap and we can then compare.

If you have any question at all, then desolder the cap, and measure on a cap meter. But at that point, like above, I'd recommend replacement to be sure and safe.

Madien3388
02-11-2009, 10:37 PM
Thank you very much Bart. Indeed, only this endcap material seems to be damaged, and I agree with you, "high" temperature or irregular glue may have done this. The other endcap is OK as seen in this picture.
Having such endcap could have changed the capacitor value?
If this shunt capacitor was dead, what should I notice in the sound ?

I'm going to buy the capacitor, just in case first (I only did basic soldering when I was at school, I have no significant experience and no material). Which ones to choose : Kimber or Auricap ?

Thanks again, it is great to have JBL fans all over the world :)

Damien

Ian Mackenzie
02-12-2009, 02:08 AM
Both brands are ver similar and I suggested them as they are similar to a paper and oil (without the coloration and do not exhibit the brightness of the trendy polyropolyne metalised capacitors) and would blend well with the mylar that are used elsewhere in the crossover.

You need some tools.

A sharp short knife to gently cut and lift the hot melt glue.

You will find the glue will lift quite easily but take care.

A solding iron 50 watt, solder wick or solder sucker (mechanical) to remove the solder on the joint (so not heat and force)

A hot melt glue gun. Cut the leads to length and strip the insulation and ensure the parts fit the pcb holes before applying hot melt glue.

Apply a modest amount of glue and insert the capacitor. The glue will cool in a few minutes. The solder leads to the pcb foot prints with resin core solder.

The board should clip apart and the terminals should allow you to remove the to pcb to work on it.

Use an strong light and take your time.

Ian

Madien3388
02-12-2009, 10:59 AM
Thank you very much Ian. Now I have to be sure to translate correctly your pieces of advice, it is very technical for me :)

Here is my conclusion following all your pieces of advice :

The glue under all the 4 capacitors on this filter is the same (same colour, same aspect). All capacitors seem all original JBL ones (Mexico). So I think this capacitor was damaged when the filter was originaly built. The endcap was damaged by soldering, glue ...
As all speakers (internaly and cosmetics) are absolutely in MINT conditions, previous owner was as at least as crazy and maniac as me :) and took a lot of care of them. So, if the capacitor was really damaged, he should have noticed it in the past after so many years, shouldn't he ?

As it is always annoying to have little default, I'm going to buy spare capacitors and wait until I have done deeper listening tests before replacing it. It seems reasonable.

Is it possible to test the capacitor without unsoldering it from the filter ?

Kimber and Auricap are very similar but not equivalent: will the speakers sound differently with them ?

Many thanks again for your help.
Damien

Ian Mackenzie
02-12-2009, 11:59 AM
Are you asking for advice?

Plese read my previous post

The read the Sonic Craft web pages

grumpy
02-12-2009, 12:32 PM
Is it possible to test the capacitor without unsoldering it from the filter ?It is -possible- to test the entire crossover... the question might be, is it possible for -you-?
It's not trivial, and requires a both a measure of instrumentation that is not
particularly common and a fair bit of experience.

If they were mine, I probably wouldn't do anything. Have you asked Chas about his
stock spare parts? It seems that the priority is having them -look- 100%... at least
that is the impression that I am getting.

If you are planning on mucking with the caps, I'd suggest you replace them in pairs
(one on each L/R) crossover in the same location/value, so you don't have a
different itching concern to keep you awake at night.

Best regards,

-grumpy

Madien3388
02-12-2009, 11:06 PM
Thank you for your help !

Ian, I'm going to "learn" what you have told me in your previous message, so that I will be able to intervine on the filter (I think it is not so complicated to solder the capacitor, but indeed it has to be done carefully).

During this "learning" phase, I'm going to buy the spare capacitors and I will do many listening tests with friends of fine to find out if the speaker's sound differs from the other speaker or not.

As said previously, there might me nothing on this capacitor as all capacitors of this filter seem to have the same "age". I think, is is an assumption, that the capacitor was llittle damaged when it was originally mounted in the filter 25 years ago. I do not think high current could damage only one endcap of only one capacitor. Entire capacitor would have been damaged and probably other components would have been damageed too.

I really want to learn how to replace some components on the filter, as I will probably need to do it in the future (the filter components won't last forever, will they ?...).

My questions are more : is it really recommended to replace components ? does it change the sound significantly ? Does it improve the speakers ?
(I have seen the Clark experience on 4345 speakers and as said in the post, the modifications were made for Clark project only and may not be appropriate for other persons).

Grumpy, I have been told that it is possible to test the capacitor only. Indeed, it will be too difficult for me to test the entire crossover... Do you know about testing only one capacitor (without dismounting it)

Thanks a lot!
Damien

grumpy
02-13-2009, 11:05 AM
I have been told that it is possible to test the capacitor only. Indeed, it will be too difficult for me to test the entire crossover... Do you know about testing only one capacitor (without dismounting it)One can test for value and leakage. To do a simple/adequate test with
hobbyist level equipment (DVM with capacitor reading) would require lifting
at least one leg from the circuit board.

In-circuit testing would require a signal generator, oscilloscope, and a few
years at university. You could check that it wasn't shorted out (assuming there
are no inductors or low value resistors in parallel), and that it passes
signal (not open to AC waveforms).

Leaving the boards alone (if differences between speakers is not heard) is
a good path. Replacing worrisome elements, in pairs, on both speakers, is
also a good path. Do keep in mind that a soldering iron can easily ruin
the circuit board, damage parts, damage you... and that removing parts
is much more difficult than installing them (adding to Ian's brief instructions
and admonitions).

Hope all goes well and you get much satisfaction and enjoyment from your
speakers! :)

-grumpy

Madien3388
02-13-2009, 11:28 AM
Many thanks Grumpy. Indeed, it is a little risky ...

A friend of mine told me that this "shunt capacitor" could be linked to the crossover of the horn. In the worse case, if its value has changed, it could have modified the crossover which could result in damaging the horn.
So I want to be sure that it is OK.

I have been adviced to call a shop near my home where people have good experience in this kind of operation. I will remove the board and ask them to measure the value of the capacitor.

Damien

Madien3388
02-13-2009, 12:58 PM
A friend of mine has just told me that he has a LCR meter. I am not an expert at all in this, but according to what everyone told me, even with this device I still need to remove one leg from the capacitor, don't I ?
Thank you very much
Damien

Mr. Widget
02-13-2009, 01:41 PM
...even with this device I still need to remove one leg from the capacitor, don't I ?Yep. :banghead:

From looking at your pics I'd assume the damage was done during manufacturing... had anyone noticed earlier it could have been replaced under warranty. It may not actually affect performance though.


Widget

Ian Mackenzie
02-13-2009, 03:21 PM
I would suggest your conclusions are assumptions.

A lot of people would never remove the woofer least know a strange looking capacitor and even do nothing about it

The worst case senario is the capacitor value may have drifted and most likely reduced or open circuit.

The effect would be the horn filter would be non optimum but it would not damage the compression driver.

One simple test is to remove the capacitor and test its value with a suitable meter. Its is measures within 5% I would say its good. Compare to the other one.

Decide as you wish.

But I can tell you significant improvements can be made by bypassing the biamp switch and using better capacitors. The simpler way to do this is have someone assemble a charge - coupled newtork and remove the stock network and put it in a safe place.

Madien3388
02-13-2009, 11:40 PM
You're right Ian.
I'm going to find someone to help me to measure the value of this capacitor. So I will know if it is good or not.

Regarding the improvment of the filter by bypassing the bi-amp switch, I would be ready to try this but only if I can keep the orignal crossover filter. I'm not sure I have understood well, but the charge - coupled newtork you speak about would replace the entire original network ?
That means that I have to find replacement networks so that I can tweak them and keep the original networks in a safe place (in case of resell).
That is correct ? Does it need do remove the little plate (where 4344 is written) in the front of the speakers to remove the crossover filters ?

And, where to find such networks and do you know someone trustable to do that ?

And again many thanks for your help, I really appreciate it
Damien

Ian Mackenzie
02-14-2009, 03:34 PM
You're right Ian.
I'm going to find someone to help me to measure the value of this capacitor. So I will know if it is good or not.

Regarding the improvment of the filter by bypassing the bi-amp switch, I would be ready to try this but only if I can keep the orignal crossover filter. I'm not sure I have understood well, but the charge - coupled newtork you speak about would replace the entire original network ?

Yes
That means that I have to find replacement networks so that I can tweak them and keep the original networks in a safe place (in case of resell).

That is correct ? Yes Does it need do remove the little plate (where 4344 is written) in the front of the speakers to remove the crossover filters ?

No

And, where to find such networks and do you know someone trustable to do that ?

It depends on how patient you are (its takes a while to organise) .Member 4313B has been kindly assisting some members in his own time. I have made the odd network from time to time.

And again many thanks for your help, I really appreciate it
Damien

See above

Madien3388
02-15-2009, 02:46 AM
See above


Thanks Ian.

So I will test the capacitor this week.

I'm not in a hurry to upgrade the crossover filters of my 4344. But I think it could be great to take advantage of these amazing speakers with the benefit of up to date new and modern filters.
If you have information on this in the next days or months, of course I will be very interested.

I will let you all know when I will have tested the capacitor. I hope everything will be fine.
Damien

Madien3388
02-15-2009, 08:59 AM
I would like to learn more about modern capacitors and their benefits in comparison with old JBL original ones. Has anyone already tested several types of new capacitors to replace the original ones of the vintage JBL filters ?

To summarize, there are the following brands:
-Kimber
-Auricap
-Solen
-Hovland

Chas and Ian adviced me some of these. As I might have to replace the damaged capacitor (and also I will probably upgrade the filters in the next months), I would like to know what would be the better choice.

Modern capacitors bring better resolution, more accurate sounding, so if someone knows the different benefits of some of these models, it would be great.

Many thanks!
Damien

Ian Mackenzie
02-15-2009, 12:56 PM
If you can find a cheap Mylar capacitor put that in there but frankly I dont see the point if you test the capacitor and its okay or you plan to upgrade.

doodlebug
02-15-2009, 05:58 PM
Has anyone already tested several types of new capacitors to replace the original ones of the vintage JBL filters ?

To summarize, there are the following brands:
-Kimber
-Auricap
-Solen
-Hovland

Many thanks!
Damien

Here's a thread over at AudioKarma with links to quite a few capacitor shootouts.

http://www.audiokarma.org/forums/showthread.php?t=210594&highlight=capacitor+shootout

IMHO, you are asking question that has as many opinions as there are posts. Ultimately, there is no right answer.

Hope that helps.

Cheers,

David

Madien3388
02-16-2009, 01:59 AM
Thanks !

Yes I will test the capacitor and will of course keep it if it is OK.
If it is damaged, I will indeed find a Mylar one to let the filters as orginal as possible.
And in the next weeks/months, I'm going to find another pair of filters to tweak them with better components.
Damien

Madien3388
02-16-2009, 02:43 PM
So, I have tried to remove the board where the capacitor is but bad surprised, the inner wires from the L-pads has been soldered to the filter! There is no way to remove them. I have tried very hard but I am afraid to damage the cables or connexions.
Because of these solderings, there is no way to remove the filters from the cabinets.

Now it is impossible to bring the filter to the shop to measure the capacitor...
I have to remove the solderings but if I make a mistake, it will be very difficult to put the cables in place afterwards.

Is it possible to remove the solder on this little connexion ?

Many thanks
Damien

Ian Mackenzie
02-16-2009, 05:42 PM
I am not surprised.

The terminals were loose on the 3145's I have examined.

You would need to suck/wick out any surplus solder and possibly heat while lifting with pliers.

Given the way this is panning out I would leave sleeping dogs well alone.

Ian

Madien3388
02-17-2009, 12:35 AM
I am not surprised.

The terminals were loose on the 3145's I have examined.

You would need to suck/wick out any surplus solder and possibly heat while lifting with pliers.

Given the way this is panning out I would leave sleeping dogs well alone.

Ian

Thanks Ian
By "Given the way this is panning out I would leave sleeping dogs well alone", do you mean that I should let the filter as it is and avoid to try to unsolder the pliers ?

I have 2 possibilities

1) Test the speaker without removing the capacitor:
- a) First test : In bi-amp mode, I turn the L-pad gain at the minimum for the 2122 and 2405, and switch the bass amplifier off. So that only the horn will be at normal level. In this way, I could listen (women voice track for example) to see if I can hear some differences between the 2 speakers.
I don't know if it is a good test or not, but I least I could isolate the horn sound.
- b) Other test possible: With my measurement device, I could also do some measures with horn L-pad gain to the minimum on both speakers, and another measure with gain at maximum to see if the horn curves are the same.
- c) Last possibility, to use a LCR meter directly on the "damaged" capacitor and measure the value (without unsoldering a leg). Then do the same measure on the other speaker's capacitor. Even I do not measure the capacitor value itself, I should find the same value in both speaker, shouldn't I ?

2) If I want to improve the original filters or replace them with modern ones, I will be obligated to remove these solderings on the pliers... So, even if the solution 1) is a good idea, I have to find a way to remove these pliers.

What do you think. Are solution 1) possible or irrelevant ?

I am very impressed of the knowlegde of most JBL forumers on audioheritage. It's great to learn so much about improving and better using such great speakers.
Thanks again for your help !
Damien

Ian Mackenzie
02-17-2009, 02:03 AM
I think you will have great trouble making any measurments and comparing them.

Save your effort the upgrading the networks.

What you should do is calibrate the L Pads.

I wrote a simple but highly accurate means of doing this in the 4343-4344 upgrde thread.

Ian

Madien3388
02-17-2009, 03:13 AM
I think you will have great trouble making any measurments and comparing them.

Save your effort the upgrading the networks.

What you should do is calibrate the L Pads.

I wrote a simple but highly accurate means of doing this in the 4343-4344 upgrde thread.

Ian

Thank you Ian

To upgrate the network, I will need to remove the original ones. Do you think it will be feasible to remove the solder on the pliers, without damaging them ?
Damien

ratitifb
02-17-2009, 04:14 AM
from my opinion it would be better to remove all terminals and re soldering all stripped wires directly on PCB

(depending on your skill and hardware availability)

take pictures and schematics before removing all wires ;)

Madien3388
02-17-2009, 04:45 AM
from my opinion it would be better to remove all terminals and re soldering all stripped wires directly on PCB

(depending on your skill and hardware availability)

take pictures and schematics before removing all wires ;)

Thanks Ratitifb, but if I do that, I will not be able to remove the filters from the cabinets anymore.
I would like to replace the networks within the next months, so I need to keep the connexions with "pliers", so that the cables can be easily deconnected.
Damien

Ian Mackenzie
02-17-2009, 04:59 AM
I could not comment without working on it directly.

As I said leave it alone .....look for trouble and you will find it.

Based on your posts you really need someone qualified on site to look at it.



Ian

Madien3388
02-17-2009, 07:41 AM
I could not comment without working on it directly.

As I said leave it alone .....look for trouble and you will find it.

Based on your posts you really need someone qualified on site to look at it.



Ian

Thanks Ian, you didn't plan to come for a trip to Paris in the next months ? :D

Madien3388
02-18-2009, 02:13 AM
Ian, one question please: Are you sure this capacitor is linked to the 2421 horn ? Would it be the 2405 instead ?
Because I have noticed (with my measurement device) a significant difference of level between the 2405 level between the 2 speakers.
Thanks
Damien

ratitifb
02-18-2009, 04:57 AM
By doublechecking the 3145 Xover schematic and seeing your previous picture of the gooped capacitor (printed as C7 on PCB) we can understand that only C7 in HF section is equal to 3µF ;)

A new problem with UHF :blink:

http://audioheritage.org/vbulletin/showthread.php?t=306&highlight=3144+schematic

Ian Mackenzie
02-18-2009, 05:53 AM
Ian, one question please: Are you sure this capacitor is linked to the 2421 horn ? Would it be the 2405 instead ?
Because I have noticed (with my measurement device) a significant difference of level between the 2405 level between the 2 speakers.
Thanks
Damien

That is probably the tolerance between the 2405 drivers , the L pads or your measurments.

Yes I am sure.
http://www.audioheritage.org/vbulletin/showpost.php?p=142746&postcount=4

Madien3388
02-18-2009, 06:11 AM
By doublechecking the 3145 Xover schematic and seeing your previous picture of the gooped capacitor (printed as C7 on PCB) we can understand that only C7 in HF section is equal to 3µF ;)

A new problem with UHF :blink:

http://audioheritage.org/vbulletin/showthread.php?t=306&highlight=3144+schematic

I'm not sure to have understood well... Could you please explain in more details for newbie ;-)
Thanks
Damien

ratitifb
02-18-2009, 07:05 AM
;)

Chas
02-18-2009, 07:33 AM
Now that's a clear answer! Nicely done.:)

Madien3388
02-18-2009, 08:12 AM
Thanks! I thought you were saying that the gooped capacitor did have the good value.
Now it is clear. Indeed the only 3 microfarads capacitor is for UH.

Regarding the UHF, I can have the same level between the two 2405 by adjusting the L-pads. I think one of the 2405 may have indeed a lower level, or the L-pad is not as good as it used to be. But everything's working normaly.

Madien3388
02-18-2009, 08:33 AM
As I am quite stubborn when I have something in my head, I have realized that in the first picture, we can see easily the solders on the pliers.

If I use a solding iron (50 watts), is it possible to remove all the solder within each plier ? I do not see that as difficult but I may be wrong : by touching the solder a few seconds, the solder should go and relieve the plier, shouldn't it?

If there is still some solder on the rod after having removed the plier, I could use the solding iron one more time with a mechanical solder sucker ?

As we say: you have to target Mars to reach the moon... I am motivated

Chas
02-18-2009, 08:57 AM
Some may think this is a heresy, but given the situation your in....you could simply cut the capacitor lead on one side between the body and the board to remove it from the circuit for testing purposes and splice it back together afterward.

Not pretty, I know.:(

ratitifb
02-18-2009, 09:11 AM
you could simply cut the capacitor lead on one side between the body and the board to remove it from the circuit for testing purposes and slice it back together afterwards.good idea ;) that I have not dared to suggest :p
(but take care to don't lose the small piece of wire soldered on PCB when heating and resoldering with a strapp ... don't overheat capacitor !)

Regarding connecting part and to avoid overheating on the PCD Cu layers ... it should be better to remove all connecting parts directly from PCB and replace them by new ones ...

After having removed all wires with soldered connecting parts you have time to heat and clean/replace all different elements.

Madien3388
02-18-2009, 12:43 PM
Another solution, quite similar, would be to cut the cables. Bring the board to a shop able to do a good job : then they would remove all connecting parts directly from PCB and replace them by other ones ...
But is it still possible to find the rods soldered on the PCB and also the same pliers ? And I think it is required to have a special tool to install the pliers on the cables.

grumpy
02-18-2009, 02:26 PM
Personally, if I was going to remove the board, I'd hold the crimped on connector
(part with the wire on it)http://tnblnx3.tnb.com/emAlbum/albums/Stakon/sk_1_g_noninsfemdis250_0_ph.jpg

with small needle-nosed pliers at the crimp, heat the bottom of the connector and
male tab on the board, then separate the connector from the male tab once the
solder melts (may need to 'wiggle' the connector from side to side while pulling).

Then clean up the tabs/connectors with solder wick (copper braid intended for this
use), so that the connectors will slip back onto the spade lugs later.

Cutting all the wires, and then re-installing new connectors would also work if the
proper crimp tools were available, and there is some slack in the wire such that
a few cm less would not be a problem.

ratitifb
02-18-2009, 03:23 PM
if the proper crimp tools were availablean alternative only is to solder wire in crimp area ...

4313B
02-18-2009, 03:32 PM
I have realized that in the first picture, we can see easily the solders on the pliers.That's because those faston connectors are crap after 30 years if left unsoldered. Just heat them up and pull the female fastons off the male fastons. It's nice to see that someone took the time to solder those puppies together.

Madien3388
02-19-2009, 01:18 AM
That's because those faston connectors are crap after 30 years if left unsoldered. Just heat them up and pull the female fastons off the male fastons. It's nice to see that someone took the time to solder those puppies together.


Many thanks to all of you for your help, I really appreciate. I would like to be able to help you one day in return but obviously I have less electronic skills than you have.

4313B, the way you describe it, it seems quite easy to remove the solder from the pliers (of course if I do it carefully).
According to other pieces of advice, there is some risk to do that because it could damage the PCB due to the high heat of the soldering iron. What do you think ?
Perhaps, as the solder is in the middle of the female faston (as seen in the picture), it could be difficult to have access to it ?

The best would be to remove the solder of the pliers as you describe, hopping that the pliers will be able to enter in the male faston without having to replace them by new ones.
Damien

Madien3388
02-20-2009, 02:45 PM
Has anyone got the book "solder for the dummies" ? :)
I have found this soldering iron. I'm not crazy, I won't do anything if it is too risky. So if you could tell me if it is the correct tool to try to remove the solders on the pliers, it would be great.
My only goal is to remove the solder on the pliers so that I can disconnect the pliers from the filter. I will let a professionnel shop testing the capacitor.

Here are some pictures. There is a "potential balance" in the back. I have no idea of the temperature of this solering iron. Is it better to use it at the lowest temperature ?
Tomorrow a friend of mine will give me another else soldering iron. So, more chance to find the good one.

Have a nice week-end
Damien

grumpy
02-20-2009, 03:00 PM
That will do. The temperature on those is set by the tip that is installed.
Should be a "6" if it is 'normal' "7" would be hotter than is normally used
for circuits. If you unscrew the collar at the base of the chrome shaft, the
tube holding the tip slides off. ... look at the end opposite the point.

connection on the back is for grounding... used with sensitive circuits
(not this).

Madien3388
02-21-2009, 12:03 AM
That will do. The temperature on those is set by the tip that is installed.
Should be a "6" if it is 'normal' "7" would be hotter than is normally used
for circuits. If you unscrew the collar at the base of the chrome shaft, the
tube holding the tip slides off. ... look at the end opposite the point.

connection on the back is for grounding... used with sensitive circuits
(not this).

Thanks Grumpy! I've just checked and it is a "7". Is too hot ?
Should I use this or not ?
Merci !
Damien

Ian Mackenzie
02-21-2009, 12:15 AM
Unless you are skilled at this type of work you will end up making of what is not really a necessary modification a mess.

Thereis probably more solder in those connectors than you think. The problem then is to apply enough heat to melt all the solder around the male & female to then apply enough pressure to remove the male. That is tricky.

Timing is crucial and you should only do this having a lot of practise

The potential consequence of this is melting the solder on the tracks around the male and pulling the male out of the board if you apply the heat for too long. It may also take several goes to remove the solder.

You may think I am overly cautious but I have seen enough crap modifications & repairs to equipment that were attempted by those with little or know experience to know this is erring on the side of foolish.

You may get lucky and get them out but is it all really necessary?

If you are so worried about it take pics and label all the wires then snip them and take the board to a techician and have it tested and then install new female spades (after the technician has removed the females) or better still just solder the wires to the male luggs).

That as a plan makes a lot more sense. (The females are going to be bent and loose and useless after you finish trying to remove them)

If you were really stuck you could post the HF board to me Air mail and I could test it in exchange for a bottle of good French wine and a calender of the hot French ladies :D ...LOL. (I have been to France before)

I have the voltage drives of a good HF board in Circuit Tester so it would be straight forward.

The condition of that iron suggest it has been ill used and need cleaning.

Ian

Hoerninger
02-21-2009, 03:28 AM
I do strictly second what Ian has said. Soldering is a skill.

I am not out for the calender - France is in the neighbourhood, but a good BORDEAUX ... ;)
____________
Peter

Madien3388
02-21-2009, 04:33 AM
Unless you are skilled at this type of work you will end up making of what is not really a necessary modification a mess.

Thereis probably more solder in those connectors than you think. The problem then is to apply enough heat to melt all the solder around the male & female to then apply enough pressure to remove the male. That is tricky.

Timing is crucial and you should only do this having a lot of practise

The potential consequence of this is melting the solder on the tracks around the male and pulling the male out of the board if you apply the heat for too long. It may also take several goes to remove the solder.

You may think I am overly cautious but I have seen enough crap modifications & repairs to equipment that were attempted by those with little or know experience to know this is erring on the side of foolish.

You may get lucky and get them out but is it all really necessary?

If you are so worried about it take pics and label all the wires then snip them and take the board to a techician and have it tested and then install new female spades (after the technician has removed the females) or better still just solder the wires to the male luggs).

That as a plan makes a lot more sense. (The females are going to be bent and loose and useless after you finish trying to remove them)

If you were really stuck you could post the HF board to me Air mail and I could test it in exchange for a bottle of good French wine and a calender of the hot French ladies :D ...LOL. (I have been to France before)

I have the voltage drives of a good HF board in Circuit Tester so it would be straight forward.

The condition of that iron suggest it has been ill used and need cleaning.

Ian

Many thanks Ian for your help. I am a little lost. You are obviously right. It would be the best to send you the boards, that is very kind of you. And I would be pleased to offer a very good bottle of French wine ans Spanish typical products (my wife is Spanish) (and a good meal too if you were in France).
But it is also risky: I would not like the boards to be lost. I would be in a very bad position if filter parts were missing...

To send you the boards, I would need to cut the wires. But I would like to keep pliers on the cables so that I will be able to replace the filters by new ones in the future (original ones would be carefully stored).
So if I send you the boards (I assume I would have to send you boards of both speakers), would you need to replace the male connectors by another ones and would it be possible to find the same pliers ?
Regarding cables, as some of the cables can not be removed from the cabinets, I would need to find new pliers here in France. And I do not know if we still can find this model of plier and the tool required to add them on the cables...
I am not in a hurry. I want the speakers to be as original as possible, and in perfect condition as they are now.
Damien

4313B
02-21-2009, 06:13 AM
According to other pieces of advice, there is some risk to do that because it could damage the PCB due to the high heat of the soldering iron. What do you think ?What I think is that I just don't have any problems doing this stuff. Yeah, there was a time when I burned a few things up "practicing" but that was a long time ago.

Madien3388
02-21-2009, 06:43 AM
I have just found some faston models :

http://www.parts-express.com/pe/showdetl.cfm?Partnumber=095-286

http://www.gotronic.fr/catalog/connectique/connectframe.php?page_cible=faston.htm

I think it is the easier way, much less risky. I cut the wires just after the female fastons and bring it to the pro shop.
I would only need to replace the fastons by new ones. By chance, perhaps the male fastons would not need to be replaced ?

What kind of female fastons do I need : in brass, copper, gold plated, diamond platinium rhodium plated :) ?

Just for my personal information, what kind of metal shall be used for soldering ? (I have been told that the method was not the same 25 years ago, now you can't use lead, ...)

Whatever the solution will be chosen, I think some people will have deserved a good bottle of French wine ...:)
Damien

hjames
02-21-2009, 07:15 AM
This needs to turn into a basic lesson - How to solder ... :blink:


Recommended tip: Get an old junk radio or cassette deck or something similar and practice on that before you go for it on your crossover ...
I'd REALLY suggest you learn on something you don't care much about!
:D

Madien3388
02-21-2009, 07:55 AM
Oh no, I have decided not to remove the solder myself. Ian and most of you guys have much more experience than I.
I do not want to damage the speakers.

I'm waiting for some confirmations : is the idea to cut the wire the good one ,
What kind of female fastons should I use ?

Then, I will go to the pro shop and they will do the work. If I see that they are not good enough, I will see that with Ian who nicely proposed to help me...

Many thanks for your help
Kind JBL regards :)
Damien

Robh3606
02-21-2009, 10:10 AM
Hello Damien

Do you have any idea when they were soldered by the previous owner?? The reason I am asking is if it was 10 years ago it would be a solder contaning lead. Within the last couple of years with ROHS in place it would probably be a lead free solder.

You can't mix lead free and lead solders. You will end up with a very brittle solder joint at the interface between them and they will not wet properly. Keep that in mind. If you decide to change out the soldered PCB connectors they will certainly be a Lead solder such as Sn60 or 63. You would need to use a lead solder to replace them because the PCB traces are commonly tinned with Sn60 as an example. Sn60 has a 40% lead content

Not trying to add more confusion but you really should discuss this with whoever does the repair for you. Same thing with the Capacitor. If it needs to be changed you need to use a lead based solder NOT A LEAD FREE solder.

Rob:)

Ian Mackenzie
02-21-2009, 10:12 AM
Many thanks Ian for your help. I am a little lost. You are obviously right. It would be the best to send you the boards, that is very kind of you. And I would be pleased to offer a very good bottle of French wine ans Spanish typical products (my wife is Spanish) (and a good meal too if you were in France).
But it is also risky: I would not like the boards to be lost. I would be in a very bad position if filter parts were missing...

To send you the boards, I would need to cut the wires. But I would like to keep pliers on the cables so that I will be able to replace the filters by new ones in the future (original ones would be carefully stored).
So if I send you the boards (I assume I would have to send you boards of both speakers), would you need to replace the male connectors by another ones and would it be possible to find the same pliers ?
Regarding cables, as some of the cables can not be removed from the cabinets, I would need to find new pliers here in France. And I do not know if we still can find this model of plier and the tool required to add them on the cables...
I am not in a hurry. I want the speakers to be as original as possible, and in perfect condition as they are now.
Damien

L'alternative est que je viennent (par l'intermédiaire des îles grecques) un peu plus tard par année et nous pouvons comparer des produits ! Je connais également quelques bonnes gens audio à Paris. Si vous êtes vous inquiétiez des panneaux obtenant perdus envoyez votre épouse vers le bas ici pour holiday..sh e serez bien occupé ! Ok sérieusement son jusqu'à vous. Vous pourriez envoyer le courrier recommandé de conseils. Plan B. Médecins Who' ; dossiers de croisement de s : J'ai attaché quelques images (j'ai travaillé à ces derniers avant). Si c'est assez de longueur de câble dans le manche vous pourriez dévisser le panneau de croisement ; de l'arrière et du mouvement vers l'ouverture de woofer. Notez que les fils d'entrée sont marqués le & E1 ; E2. Son possible vous devez seulement enlever ces femelles et unclip (6) les agrafes et adoucir le tour la carte plus de pour accéder au dessous de la carte. Là de vous peut gentre enlever la soudure sur les garnitures de soudure du condensateur et l'enlever pour l'essai. Vous pouvez voir des images les connecteurs et il est tout à fait possible la soudure excessive pourrait être mauvais outre du mâle. Mon expérience était les femelles étaient lâche et attemping pour faire à la femelle meilleur convenable était seulement marginalement meilleur. Par conséquent le propriétaire précédent de votre croisement a décidé la soudure elles mais comme vous pouvez voir elle a a a dessiné en arrière si vous avez l'intention d'enlever ou accéder aux conseils. Vous pouvez également pouvoir à la mèche la soudure hors de la femelle mais il est probable vous devra souder de l'autre côté s'ils sont lâches. Je proposerais que le plan ci-dessus B soit la meilleure ligne de conduite de vous décident de faire quelque chose à distance.Je suis sûr que les pinces peuvent être remplacées pendant que j'employais beaucoup pour l'essai de ces croisements. (J'aurai une recherche vous)

The alternative is that I come over (via the Greek Islands) a bit later in the year and we can compare products! I also know a few good audio people in Paris. If you are worried about the boards getting lost send your wife down here for a holiday..she will be well looked after!

Okay seriously its up to you. You could send the boards registered mail.

Plan B.

Doctors Who's crossover files:

I have attached some images (I have worked on these before).

If these is enough length of cable in the loom you could unscrew the crossover panel; from the rear and move towards the woofer opening.

Note that the input wires are labeled E1 & E2,. Its possible you only need to remove those females and unclip the (6) clips and gentle turn the Pcb over to access underside of the Pcb. From there you can gently remove solder on the solder pads of the capacitor and remove it for testing.

You can see from the images the connectors and it is quite possible the excess solder could be wicked off the male. My experience was the females were loose and attemping to make the female fit better was only marginally better. Hence the previous owner of your crossover decided the solder them but as you can see it has a draw back if you intend to remove or access the boards. You may also be able to wick the solder out of the female but it is likely you will need to solder then again if they are loose. I am sure the pliers can be replaced as I used a lot for testing of these crossovers. ( I will have a look for you)

I would suggest the above Plan B is the best course of action of you decide to do something remotely.

Ian Mackenzie
02-21-2009, 10:15 AM
Roberto makes a good point.

Ian Mackenzie
02-21-2009, 10:40 AM
I still think this is all a lot of meddling for what is most likely nothing.

If the leaking(?) capacitor was off its value there would be some audiable channel mismatch between channels. But as I said earlier unless you match the L pads of both channels exactly there is nothing to get too excited about. The positions on the L pads are not accurate) and good matching of both channels is important if the speaker are to image at all properly. A 1/2 a db in level here and 1/2 a db there across the mid/horn and slot means you could have a 1 or more db variation between channels. This will cause not only a shift in the images (loss of focus) but the tonal balance will be also different. I found the 3145 improved quite a bit from being a good loudspeaker to an excellent loudspeaker when you take care to obtain very close balance. Its a bit like sharpening up an axe.

The point being the potential issue of the capacitor is moot compared to proper adjustment of the L Pads.

Ian

Madien3388
02-21-2009, 12:44 PM
I have already said it a large number of times but many thanks for your patience and help, I really appreciate. it helps me a lot.

I would like to try the plan B but I will let a professional do the job. My only concern is to remove the filter from the cabinets; for this, I have to remove the solder on the fastons with only 2 possibilities :
- 1) I try to remove the solder from the fastons myself, but it is very risky
- 2) I cut the cables, just after the female fastons and bring the PCB to a professional : he will test the capacitor and will remove the solder on the female fastons. I would only need to add new female fastons myself on the cables.

For example, Chas doesn't have solder on its 4345 fastons and he doesn't have any issue. I would really like to have fastons plugged in the male fastons without any solder (it is the more practical solution if I want to replace the filters in the future).
If you think this solution is a good one, I will do that. Ian, if you could advice me someone in Paris who could do this job carefully, I will feel better. It is more and more difficult to find good and honest persons in audio highend those days.
I would only need to find this rare person, who will do the solders properly, to be sure that the PCB & male fastons could be keep safe.
Damien

Ian Mackenzie
02-21-2009, 02:03 PM
Pm sent.

Ian Mackenzie
02-21-2009, 06:35 PM
I have already said it a large number of times but many thanks for your patience and help, I really appreciate. it helps me a lot.

I would like to try the plan B but I will let a professional do the job. My only concern is to remove the filter from the cabinets; for this, I have to remove the solder on the fastons with only 2 possibilities :
- 1) I try to remove the solder from the fastons myself, but it is very risky
- 2) I cut the cables, just after the female fastons and bring the PCB to a professional : he will test the capacitor and will remove the solder on the female fastons. I would only need to add new female fastons myself on the cables.

For example, Chas doesn't have solder on its 4345 fastons and he doesn't have any issue. I would really like to have fastons plugged in the male fastons without any solder (it is the more practical solution if I want to replace the filters in the future).
If you think this solution is a good one, I will do that. Ian, if you could advice me someone in Paris who could do this job carefully, I will feel better. It is more and more difficult to find good and honest persons in audio highend those days.
I would only need to find this rare person, who will do the solders properly, to be sure that the PCB & male fastons could be keep safe.
Damien

For clarity what I was saying in the previous post is that there is less risk in unsoldering only (2) of the fastons E1 & E2 than all the others.
Then you would need to remove the capacitor or unsolder at leat one end and then test it with a multi meter that has capacitance range (Most do).
This could be done on site without removing all the other fastons given the caveats I mention earlier and would be least invasive or the original work.

However the previous owner has done some invasive work (solder fastons) and you may find more once you turn the pcb over. Therefore you need to decide of you want to return the crossover to original factory condition without solder on any of the fastons or just explore the capacitor?

One point I will make is that capacitors are strange devices and a simple measure of capacitance may not tell you everything about its condition.

As this capacitor is not in series with the driver if it is intermitantly faulty you may not be aware of this. This type if fault is more common in high voltage circuits like in Televisons and RF devices.

So you have (2) two options, try and do an site inspection and a simple test of the capacitor OR snipe all the wires and take it to someone and have the females removed and replace the females on the sniped wires on return of the HF board for re installation.

One question, Are all the other fastons on the woofer/mid board also soldered?

One of the problems with this type of activity is the more you look the bigger the job becomes and what might appear a simple exercise can become a headaches...(trust me I know)

The reference may actually reside in Zurich..I cannot remember.

In the Link below are some knowledgable Forum members, most of them are in Europe.

If you go to the front of the thread you can see the location of some members. rs237 in the green shirt is quite unassuming but very clever in my view and has a good sense of humour. There are other members who might be able to assist.



http://www.audioheritage.org/vbulletin/showpost.php?p=187619&postcount=187


Ian

Madien3388
02-21-2009, 11:25 PM
Many thanks Ian
Yes, my aim is to return the crossover to original factory condition without solder on any of the fastons.
In this way, the filter could be removed easily from the cabinet; and I could bring the PCB to someone professional to test the capacitor.

I forgot to tell that only 7 of the 10 fastons were soldered. E1 and E2 are not soldered. It is strange.
I have already looked under the PCB and all solders are normal, nicely done.
Damien

grumpy
02-23-2009, 07:08 AM
it is a "7". Is too hot ?

Sorry for the late, and out of order response...

a "7" is too hot for delicate component work and will cause
the circuit board to blister and separate the traces/pads from
the board -if not used very cautiously-. It is still useful in trained/
experienced hands, but not a tool I'd recommend to a novice.

Madien3388
02-23-2009, 12:27 PM
Today I did what I was not supposed to do. I tried to use a soldering iron.
But don't be afraid, I tried 5 seconds on a part without risk and decided that it was definitively too risky for me.
When looking in details the all filters from both speakers, I have found that other fastons were soldered in the other speaker (the one where there is no issue on capacitors). So, as a conclusion, if I want to remove the filters from the cabinets, I will need to disconnect all wires from all drivers and also remove the front L-pads. It is not a big deal, I will only need to remove the front plate (where 4344 is written).

Furthermore, I have received some more pieces of advice today. Even if the capacitor has gooped a little, there is a very low probability that he is damaged. When listening there is no noticeable difference (but I will do some more detailed tests). Ian and Chas first told me that but, as I am very maniac with my system, I wanted to be sure :)

So as conclusion, now I know that I will be able to replace the capacitor one day if needed and also the entire filters (when I will replace them by better ones) by simply removing all wires and front panel with L-pads.
Speakers are working, so I'm going to spend more time doing what it should be done when you have the chance to have such great speakers: listen to music.
Now, if one of you knows how to find other 3144/3145 networks so that I will be able to upgrade them with newer capacitors, it would be great.

Many thanks to all of you for your help !!
Damien

Ian Mackenzie
02-23-2009, 02:05 PM
Thanks for the update.

I am very busy with current projects and domestic issues so I would recommend you contact 4313B about new networks. (Please note that where such services are offered it is done in the spare time of the individual. Therefore anticipate that it may take longer to arrange than first expected).

Ian

Madien3388
02-23-2009, 02:13 PM
Thanks for the update.

Thanks to you Ian, you really helped me a lot.
I have not finished yet as I probably will replace this capacitor, but I will only do that when I will replace the all filters by new ones.
As the speakers seem to work fine, I will wait to find these other filters. When I will replace the old ones, I will have plenty of times to test this capacitor, just in case.
Damien

Chas
02-23-2009, 06:19 PM
Madien, you will likely have a great deal of trouble finding original JBL OEM networks.
Greetings from Cuba!:)

Ian Mackenzie
03-02-2009, 12:08 AM
This is turning into a FT job but the difference is dealing with someone as a polite as Madien3388 makes it very worthwhile.

Ian