JBL C40 Harknesss N1200 Crossover Recapping

[cykotic]

Greetings:
I have an early model JBL C40 Harkess with the D130A, 175DLH, and N1200 Crossover. I would like to change the capacitors in the N1200 as they have to be about 60 years old now (or older). I opened up the N1200 and am faced with this wax/resin substance securing the caps to the inside of the metal enclosure. What is the best way to go about removing the resin to free the existing caps? Or can I bypass the removal some way and just rewire new caps into the enclosure? Any advice would be appreciated.
Thanks much,
~Cykotic

88275

[Eric M.]

https://www.youtube.com/watch?v=VAOZ9VDl2-4&t=364s

Unpotting the JBL crossover.

[BMWCCA]

Greetings:
I have an early model JBL C40 Harkess with the D130A, 175DLH, and N1200 Crossover. I always wonder when I see this load quoted if you don't really mean 130A. I know there actually was once a time when dinosaurs ruled the world but I've never actually seen a D130A, or D130-A for that matter. Does yours have an aluminum dust dome, or black paper?

Just curious. I love that system!

[Drugolf]

I just unpotted some Altec N3000 crossovers and the stuff just chipped and pulled away rather easily. I thought I was going to have to melt it off but it kinda just fell apart with some prying. (almost make you wonder if freezing it would be better than melting.) Worth a try I guess first.

[Eric M.]

I just unpotted some Altec N3000 crossovers and the stuff just chipped and pulled away rather easily. I thought I was going to have to melt it off but it kinda just fell apart with some prying. (almost make you wonder if freezing it would be better than melting.) Worth a try I guess first.

I wonder if the "stuff" the Altecs are potted in is different than the JBLs. Do you have any pictures of the pieces you got out of your Altecs?

Eric M.

[cykotic]

I always wonder when I see this load quoted if you don't really mean 130A. I know there actually was once a time when dinosaurs ruled the world but I've never actually seen a D130A, or D130-A for that matter. Does yours have an aluminum dust dome, or black paper?

Just curious. I love that system!


Black paper. Yes, it’s a 130A. I stand corrected. Still looking for the correct size uf capacitors for this crossover. I was told by the owner whom I purchased this C40 from that it was built around 1957, although I have no way of confirming this date. I do know that it the speaker came from a mono system so I feel it’s safe to assume that this C40 Harkness Lowboy is pre 1964. The .pdf schematics for the N1200 which I’ve seen on this site are dated October 31, 1977. So this schematic I cannot use UNLESS the capacitors used in both N1200 models are identical in uf. Anyone have any suggestions? I am a novice to audio repair.
Here is the link to a photograph of my N1200:

https://drive.google.com/file/d/1lYdtJTEeQpVWBd8NYuADJVoohZkCNrTL/view?usp=sharing

[Earl K]

I would use a paint-stripper ( heat gun ) and putty knife to reveal the rest of the printing that is seen on one or both inductors barely visible through the wax ( within your first pic ) .

If the parts numbers matchup with those seen below, then you're just about guaranteed that the capacitor values seen in my pic are correct.

BTW; Don't be fooled by the "Test Numbers" seen in the top "SPECIFICATIONS" box.
- No matter the actual real world load, JBL's test standard was to use an 8 ohm resistor for testing out a network's health.

89401

:)

[Earl K]

TWO More Threads for Reference : ( Click the Pics for the links )

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=18893&stc=1&d=1159001857 (http://www.audioheritage.org/vbulletin/showthread.php?12359-N1200-crossover-Exposed!!)

http://www.audioheritage.org/vbulletin/attachment.php?attachmentid=71176&d=1462048142 (http://www.audioheritage.org/vbulletin/showthread.php?38226-N1200-crossover-capacitor-number-decoding)


:)

[cykotic]

I finally got around to melting that wax resin out of the old style metal JBL N1200 crossover and ordering new capacitors. I am very new to this type of audio upgrade. As such, I need some advice. I am on PartsExpress.com and am about to order these capacitors as replacements. Are these capacitors the route I wish to take, or should I choose a different brand and composition.
Thanks
-Cy

[Earl K]

Yes, I think those Dayton capacitors are good enough for that refurbishment.

:)