My JBL 4343 repair story

[JeffW]

Those drivers look to be in really fine shape, KenDad.

[y60kuro]

Those drivers look to be in really fine shape, KenDad.

Hi JeffW Yes this is THE JBL ! KenD.

[y60kuro]

Put off front baffle , lovely shape unit guys hello . but .....

There is a clear gap in the seam of the plate. In addition there was a gap in between the cross wood bars of the reinforcement and the box . Adhesive is aging, it can be easily removed with a finger.

Can I say OMG ? ( is this right ?)



Red line is clear gap
I thought almost old JBL is same condition in Japan . If it is beautiful outer box but inner box is aging because they are same age as my 4343 .　JBL, which is sold at a very expensive audio shop also I think for the most part has become this way. They applied the wax in the maintenance of the outer surface there, modification of internal reinforcement and adhesion failure point is that there is no seen. I dont know Anymore and not sure then.






Anti JBL faction say the 43 series is not good sound because the resonance of the box is. This may have the influence not have any countermeasure such internal degradation. I think unit, with the interior of the strength maintenance of the box as well as the maintenance of the network is required. I thought I will not talk about done not when the 43 series of things to the reinforcement of the box.

How do you think ?

[ivica]

port inner dia:4 inch

Total length-face-port end :210mm

Is this OK?

Hi y60kuro,

I think than with such length Fs about 30~31Hz is something expectable for 2231/2235 bass driver in the box such as 4343 size with two vents.

regards
ivica

[mortron]

Y60kuro,

Looks good! Restoration always has hidden surprises I find. Risk is worth the reward in this case.

I haven't been to Japan, but always wanted to visit. I like that you drive a Nissan. All I have owned are Nissan: 2 cefiro and one Pathfinder (not sure model name in Japan). Very low maintenance costs... saves money for fixing JBL's

If the split in cabinet is large enough and cannot be clamped tighter, could one use a thin piece of veneer to fill the gap? That is a shame. I have seen far worse condition speakers online in very humid countries... I am starting to understand why Kenrick builds new cabinets.

Maybe you mentioned already... Will you recone and recharge the woofers too?

Keep up the good work!

[y60kuro]

Hi y60kuro,

I think than with such length Fs about 30~31Hz is something expectable for 2231/2235 bass driver in the box such as 4343 size with two vents.

regards
ivica

Hi ivica

Thank you for the information . well, I agree .

Y60kuro,

Looks good! Restoration always has hidden surprises I find. Risk is worth the reward in this case.

I haven't been to Japan, but always wanted to visit. I like that you drive a Nissan. All I have owned are Nissan: 2 cefiro and one Pathfinder (not sure model name in Japan). Very low maintenance costs... saves money for fixing JBL's

If the split in cabinet is large enough and cannot be clamped tighter, could one use a thin piece of veneer to fill the gap? That is a shame. I have seen far worse condition speakers online in very humid countries... I am starting to understand why Kenrick builds new cabinets.

Maybe you mentioned already... Will you recone and recharge the woofers too?

Keep up the good work!

Hi　mortron

I did not even think to restore the first time in the Big Old JBL.　　Also the influence of humidity of the box with the car of the rust is formidable. I know your Nissan . It is Both currently not been released in Japan, but it was a good car. (pathfainder=terano) My Nissan deprive the budget and the time of the re-cone of my JBL. Oil leak was found yesterday. This time, I have to repair the 4343, but I think that will try to remake in 4333 or 4341 someday because 4343 is too large for the Japanese housing . This repair is a shortcut for that familiar with JBL.

[y60kuro]

Box was removed all components so becomes necessary observation and repair. 2405 and 2420 also requires the maintenance there is corrosion in appearance. 　The capacitance measurement of the network of the condenser, replace if necessary, to the replacement or cleaning of the attenuator. Whether the attenuator was changed once? Although it is good in addition, the changeover SW is corrosion of 40 years.







A few days the sun drying when the weather is nice in front of the repair work.Sun drying of, including pest control, such as mites that lurk in, such as sound-absorbing material.　during this time, how to repair in any way? It was to prepare the information collection.

[y60kuro]

I began the repair of the box. First is from the cleaning of the adhesive surface. It is the repetition of work to blow off by air ,in polishing the with a file. Cracking of the rear face of the box is very weak, decided to cut out so does not make sense to also fixed with the adhesive.

This weak of looks like this is serious in the aged deterioration due to moisture.When the state of the board to use a chisels remove until firm part, it opened a big hole in this manner.The same as the repair of the rust of the old car, requires removal of the lesion.

[Krunchy]

I wouldn't be too concerned, seems like you are doing a good thorough job, take your time. Most important is to re-glue the corners and get them Squared, the hole can always be filled in later. If you truly had serious pest issues with mites I would probably remove all of the insulation, clean the hell out of the interior and put in new insulation as part of the restoration process.
Have fun & keep the pictures coming.

[y60kuro]

I wouldn't be too concerned, seems like you are doing a good thorough job, take your time. Most important is to re-glue the corners and get them Squared, the hole can always be filled in later. If you truly had serious pest issues with mites I would probably remove all of the insulation, clean the hell out of the interior and put in new insulation as part of the restoration process.
Have fun & keep the pictures coming.

Thank you　Krunchy
Although I thought I can be more easily repaired, condition is not so good. I feel the strength of the board at the moisture is reduced. Therefore it is determined that strongly involves the risk is to clamp, right angle of the corner was a compromise slightly. But I thought that as much as possible the original at first but it so unreasonable likely to think in the direction to be sound-absorbing material exchange. This repair is one of my fun .

[y60kuro]

In order to adhere the box is required big clamps . But I dont have,and dont have a plan to buy large clamp now. I tried to somehow thinking or not can be substituted with a hand-held ones.　And those that use a long screw, but I thought the various prototypes, finally decided to go with this method using a jack. I admire the men who make the new box here of forum is a real craftsman. I'm just fun .

look my funny " free style clamp "

This type is first , but need more idea ,,,. lack of power ,,,NG



Finally I will go this freestyle clamp . Yes very funny ,but works good I can adjust compression by jacks and weight
This is cooperation of toyota and nissan .

[y60kuro]

Woodworking adhesives vinyl acetate is the mainstream in Japan . I checked on the net about adhesives Titebond is good and stronger than the vinyl acetate-based adhesive yes I was ordered this. Further syringes were also prepared in order to fill the adhesive in the gap crack. Special nail to other wood part cracking and peeling measures were also secured.



For example　1 　wave nail
Use the time to fix the plate to each other.



For example 2　hide nail

Nails in pink and green plastic is attached type . After drftingnails, nail head is brought into contact with the plastic in this state,
Next to hit the plastic from the side and broken nails at the lower end portion of the plastic, not only see a small hole in the thickness of the shaft. Use fix little wood parts . but dont want to see nail head .

[mech986]

y60kuro, do you mind measuring how long the ports are..please, thanks!!! i know they are 4 inches diameter

Armed, you're very lucky to get the information so quickly!

KenD, your methods have been ingenious and very MacGyver-like. Looks like you will be able to glue down and reinforce the loosened corner. What filler and glue did you use? Some have used automotive bondo filler, others use combinations wood dust and construction wood glue, and of course a lot of pressure and elevated temperature. I've not seen humidity damage like that but have seen it in cabinets that were directly exposed to water spills or maybe open windows or poorly insulated garages?

Not sure if you have access to this but you may consider adding additional bracing to the walls, top, bottom, and back panel. You can also consider adding damping material (in the UK, bitumen sheets, in the US, Dynamat or similar adhesive backed, mass loaded) and then re-place or completely replace the insulation with new fiberglass.

Regarding the crossover and wiring, there are a few options. First, the L-pads can be cleaned - sometimes they can be opened up directly and the wiper and resistance element cleaned directly, would recommend using DeOxit Red and Gold (D5 and G5 respectively) to treat and preserved. Otherwise, they can be sprayed internally and exercised at least 50 times to get the gunk out. In some cases, people will spray and clean until no dirty residue comes out. I do not know if available in Japan, but I suspect some Audio or electronics stores will carry it.
http://store.caig.com/s.nl/sc.2/category.188/.f
http://store.caig.com/s.nl/sc.2/category.292/.f

Yes, they have a Japanese distributor who should be able to supply you.
http://www.tosy-corp.com/products-caig_new.html

The biamp switch is a difficult to clean device and to get reliable contacts, even with thorough cleaning. Considering how much corrosion is there, it may be better to consider wiring the input terminals for a direct biamp set up (bass and mid-treble-super separated and crossover wired), or just tie the inputs together for a single amp set up. Many have done that for the 43xx series biamp crossovers.

Capacitor substitution should be considered if there is a lot of corrosion, component lead or solder joint damage. They are all mylar (polyester) film types, and can be substituted with quality polypropylene or metallized polypropylene film types or other "Audio grade" types, assuming they fit the space and crossover box. The inductors are usually ok unless really corroded but wires can be restripped and reconnected. Wiring can also be repalced if needed, but usually not, just ends cut, newly stripped and re-soldered. Many will replace the input connectors with nice gold plated binding posts to allow for options on connecting speaker wire.

[y60kuro]

Armed, you're very lucky to get the information so quickly!

KenD, your methods have been ingenious and very MacGyver-like. Looks like you will be able to glue down and reinforce the loosened corner. What filler and glue did you use? Some have used automotive bondo filler, others use combinations wood dust and construction wood glue, and of course a lot of pressure and elevated temperature. I've not seen humidity damage like that but have seen it in cabinets that were directly exposed to water spills or maybe open windows or poorly insulated garages?

Not sure if you have access to this but you may consider adding additional bracing to the walls, top, bottom, and back panel. You can also consider adding damping material (in the UK, bitumen sheets, in the US, Dynamat or similar adhesive backed, mass loaded) and then re-place or completely replace the insulation with new fiberglass.

Regarding the crossover and wiring, there are a few options. First, the L-pads can be cleaned - sometimes they can be opened up directly and the wiper and resistance element cleaned directly, would recommend using DeOxit Red and Gold (D5 and G5 respectively) to treat and preserved. Otherwise, they can be sprayed internally and exercised at least 50 times to get the gunk out. In some cases, people will spray and clean until no dirty residue comes out. I do not know if available in Japan, but I suspect some Audio or electronics stores will carry it.
http://store.caig.com/s.nl/sc.2/category.188/.f
http://store.caig.com/s.nl/sc.2/category.292/.f

Yes, they have a Japanese distributor who should be able to supply you.
http://www.tosy-corp.com/products-caig_new.html

The biamp switch is a difficult to clean device and to get reliable contacts, even with thorough cleaning. Considering how much corrosion is there, it may be better to consider wiring the input terminals for a direct biamp set up (bass and mid-treble-super separated and crossover wired), or just tie the inputs together for a single amp set up. Many have done that for the 43xx series biamp crossovers.

Capacitor substitution should be considered if there is a lot of corrosion, component lead or solder joint damage. They are all mylar (polyester) film types, and can be substituted with quality polypropylene or metallized polypropylene film types or other "Audio grade" types, assuming they fit the space and crossover box. The inductors are usually ok unless really corroded but wires can be restripped and reconnected. Wiring can also be repalced if needed, but usually not, just ends cut, newly stripped and re-soldered. Many will replace the input connectors with nice gold plated binding posts to allow for options on connecting speaker wire.

Hi mech986 Thank you so much imfo
Wow! I am so surprised by your comment . you are champ. I cant write enough comment as same as yours sorry my poor English . but I can read and understand your comment well OK haha OK I am ingenious repair man . I am carefully injected deep into the repair of the corner portion of this adhesive with a syringe. The narrow gap between the needle of the syringe does not turn on,The adhesive a hole was injected with a syringe with a fine drill. It is the same way as the ground improvement work.　After that, the piece of wood was processed in accordance to this excised size, it was implanted with the adhesive. This is how to use well the time to repair the house of Japan's carpenter was corrosion.

Crossover network is the next of the fun of the repair of the unit after the end of the repair of the box. Since there is no knowledge about the network, I am going to study in this forum. Switching SW of bi-amp is not necessary for me. Direct to or placed in a network, I think that if try to bi-amp in the woofer and the rest of the unit who is using the network.

Information of seller also Thank you very much. It is very helpful

[y60kuro]

Bit off topic sorry
I got new my toy old 4311 junk model from another friend . This 4311 is he got his friend had been used in the shop for BGM ,but a few unit was gone ,not so beautiful .Yes this 4311 is sleeping in the his room about 10 years . I have 4312A and interested in OLD original 4311 sound .
Yes I got his old 4311 exchange for beer pack .











I played little 4311! WOW ! very nice sound ! I love 4311 sound than 4312 . Is this ALNICO magnet sound ?
Drived SANSUI and marantz 7T+ ALTEC 1520 replica tube amp both is good !




OK next my repair story is this 4311 after 4343.