Newbie needs help fixing CV LS 10 crossovers

[mikemtnbikes]

I got a pair of Cerwin Vega LS10 speakers from a friend when he moved away. The tweeter on one speaker, however, has stopped working. I've checked the diaphragm and it doesn't seemed blown so my understanding is the next part to replace is the appropriate capacitor in the crossover. The problem is I don't know which part of the crossover that is or how I figure out its specs so I can replace it with the appropriate part.

Photos of the crossovers (P/N: CXS-GL2050) are below.



Any guidance will be appreciated.

 

[N8Nagel]

1) I'd check the tweeter by dropping a (quiet) audio signal on it straight from your amp, if it makes noise it's the x-over. Alternately if you have a multimeter, check DC resistance of the tweeter. Should be slightly less than the nominal impedance. If it's open, the tweeter has failed and will require repair or replacement.

2) if the tweeter checks out, trace the traces on the circuit board. The culprit will be the one in series with the tweeter. However, if one has failed, I'd be tempted to shotgun and replace all caps on both x-overs, and not worry about it again for a couple decades.

 

[xero-D-hero]

Yeah I'd check the tweeter's DCR first.

From what I recall the LS-10 crossover is'nt fuse protected so it's possible that the tweeter's voice coil has been damaged,and that damage would'nt be visible.

I know the LS-12 & LS-15 are both fuse protected,but for some ???? reason the LS-10 is'nt.

Some CV's have circuit breakers instead of fuses,but that's usually noted on the back of the crossover plate,and I dont recall the LS-10 having CB's either,so honestly AFAIK they have no protection.

I doubt it's the crossover,only problem I've heard of with regards to CV X-overs has to do with those circuit breakers occasionally becoming intermitent.

Odds are the tweeter's VC is damaged and the DCR will read open...

Fix for that would be to R&R with a known good tweeter.

FWIW

Bret P.

 

[dc270]

If I know my CV's, it is probably a blow tweeter, fried resistor or half tripped circuit breaker.
DC

 

[mikemtnbikes]

Thanks for all of your comments or suggestions.

A little more background, I replaced the tweeter diaphragm about 6 mo ago and my first worry was that I blew it again. However, my voltage meter indicates it has 5.6 Ohms of resistance which is close to spec. The voltage meter also reads no voltage b/w the + and - lines going to the tweeter.

A couple of questions.

a) If it was a fried circuit breaker (assuming it has one), wouldn't the midrange and woofer also not work? Right now it's just the tweeter that's not working.

b) There look to be 5 capacitors and I believe only two relate to the tweeter. As a 'precaution' should I replace just the two for the tweeter or all 5?

c) If I replace all 5 should I use the exact same MFD's or 'upgrade', assuming I do both speakers.

d) The capacitors are all glued together w/hot melt glue. Any easy way to get them unglued?

 

[N8Nagel]

a) not familiar with those speakers so I don't know

b) I would replace all 5 on *both* speakers as they are all the same age

c) exact same capacitance rating. There is no upgrade. The capacitance rating in microfarads determines the crossover frequency, and playing with that without knowing exactly what you're doing will almost definitely result in poor performance. If you feel froggy you could replace those old electrolytics with some film caps but that will require rework to fit the much larger film caps in their place. Honestly, if you just replace like with new production like you'll be good for another 2-3 decades.

d) just desolder with a solder sucker and solder wick and then rip the old caps out. I doubt the glue is that strong. a razor blade may help.

Good luck with your speakers... I expect an update pronouncing success soon

 

[J1mbo]

Re glue - just warm with a hair-drier, not too much, and it will peel right off. Heat it too much and it will go all runny again.

 

[mikemtnbikes]

I'm learning a fair amount here and appreciate the help with such a simple problem.

I am now having a problem finding the exact replacements as NPD. I've checked PartsExpress and the 'stereo crossover' models they list are axial rather than radial configurations. Won't these be tricky to use to replace a radial cap or am I worrying too much given the long leads and the fact that i have some basic soldering skills?

Mouser has radials but w/in their 'audio quality' stock none of them are close to 6 MFD. (4.7 and 10 MFD, yes. 6 MFD no). Should I just get 'non audio quality' NPD's or is there another vendor you'd recommend.

 

[mikemtnbikes]

Brief update. I finally ordered capacitors from PartsExpress. When I couldn't find, say, a 6MFD, I replaced them with the closest value, e.g. 6.2MFD. Soldering skills are not great but I got the parts in and the speakers seem to work just as well as before.

Thanks for helping me this simple, but new territory.