Opening up/refurbing a 3105 crossover

[cooky1257]

Hello All,
I've got a noob question, can anyone give me advice on how to open these without breaking them? As part of my restoration project I thought it a good idea to check the state of the caps and maybe install some new ones.
There seems to be reddish brown wax/resin around the rear mounting plate do I cut through this or what?
I've done a few searches without success.
Thanks

[hjames]

Hello All,
I've got a noob question, can anyone give me advice on how to open these without breaking them? As part of my restoration project I thought it a good idea to check the state of the caps and maybe install some new ones.
There seems to be reddish brown wax/resin around the rear mounting plate do I cut through this or what?
I've done a few searches without success.
Thanks

Mine were metal cans with rivetted lids - once I drilled out the rivets I could lift the lid and see that inside they were half full of a mixture much like bees wax. I set it in a slightly filled pan of water and heated it up slowly, poured out the wax, and saved it in an empty tin can for reuse. Then I could get to the circuit and fix a broken solder joint.

See this thread - http://audioheritage.org/vbulletin/showthread.php?t=19084

[cooky1257]

Thanks Heather,
Frank

[richluvsound]

Frank ,

any chance of some pictures ? Perhaps you could start a thread for us ?

Those babies are pretty special

:applaud:

Rich

[cooky1257]

Hi Rich,
Will do.
I've been taking photos along the way so will post them asap.

I do have a question regards the xover freq between the 2440 / 2405.
The 3105 is 'optimised' for the 2440/2405 but has it @5.5k-ish but the pdf for the 2405 says 'from' 6.5Khz.
Would I be better off tweaking the xover freq up to (as I've seen mentioned)7.5k?
Or have JBL dealt with certain aspects of both drivers to arrive at a 5.5Khz ideal?.
Frank

[richluvsound]

Frank ,

I would ask someone like Guido, Rob , Zilch or Ian . These guys are serious heavy weights in the crossover department. I'm a hack unless you need a box building .

Rich

[cooky1257]

Frank ,

I would ask someone like Guido, Rob , Zilch or Ian . These guys are serious heavy weights in the crossover department. I'm a hack unless you need a box building .

Rich

:D
Done more research and will try the 3106-easy, just coil swaps-then use my ears:)
Frank

[Zilch]

:D
Done more research and will try the 3106-easy, just coil swaps-then use my ears:)
FrankYup, for starters.... :thmbsup:

3105's an aluminum box, no?

[cooky1257]

Yup, for starters.... :thmbsup:

3105's an aluminum box, no?

Hi Zilch, Yeah, drilling out the rivets tomorrow.
Frank

[toddalin]

When I've opened mine, I found that the parts were not "potted." Furthermore, the caps look like your typical long, thin, yellow capacitors and are not those cardboard tubes used for the larger values in other JBL crossovers. I can't see that these would leak and go bad. You may also be astounded by the chokes that are very pedestrian.