Troubleshooting a crossover in EV 1202ER speaker

[stoneattic]

I have a set of identical EV 1202ER monitor speakers that I noticed one sounding muddy and realized there was no output from the tweeter. So I swapped tweeters and did a little bit of additional testing to confirm that both tweeters are good and that the crossover was the only remaining culprit.

I have pulled both the good and bad crossovers out and measured components, checked for broken leads, etc., and both measure pretty close to spec and each other on everything I measured (caps and resistors). I'm sure there has been some drift with age, but they seem close. I jumpered past the polyswitch but still no tweeter out put. None of the cap looks bulged or any other signs of damage, but I will note that it looks like there was some moisture in there at some point as the crossover network is on a piece of particleboard that appears swollen, unlike the one that works.

Any thoughts on what I might be missing? Should I just replace all the caps and resistors and be done with it, thougt I would like to know what the problem really is?

I've attached pics and documentation, which includes the schematic, component call outs and layout.

Any thoughts would be greatly appreciated!
Thanks!

[Helmholtz]

What cap value does the 2µ cap measure out of circuit.
What inductance does the 0.73mH choke measure out of circuit?
Generally all components should be measured disconnected from circuit.

[Jazz P Bass]

Do you have a scope.
If not. Use a multimeter set on VAC.
Inject a high frequency signal into the xover.
Follow the signal through each component.

[stoneattic]

What cap value does the 2µ cap measure out of circuit.
What inductance does the 0.73mH choke measure out of circuit?
Generally all components should be measured disconnected from circuit.

Thanks for responding!
I was hoping that comparing measurements in circuit between the known good and the bad boards would be valid, but apparently it is not. The 2µF cap out of circuit is measuring 1.3nF. I should follow Enzo's advice and not make excuses not to test.
I do not have a way to measure the inductance. I measured the resistance out of circuit at 1.3Ω, so I know it's not open. Maybe this is a dumb question, but it's just a coil of wire, so if it's not open wouldn't it be okay? I guess it could be shorted, but that seems very unlikely without it experiencing some sort of trauma.
So I'm guessing my next move is replacing the 2µF poly cap?

[Helmholtz]

So I'm guessing my next move is replacing the 2µF poly cap?

Yes!
At 1.3nF the cap is essentially open, passing only ultrasonic frequencies.
To see if it's the cap only you could swap the caps between the 2 boards.

[stoneattic]

Do you have a scope.
If not. Use a multimeter set on VAC.
Inject a high frequency signal into the xover.
Follow the signal through each component.

Thanks for the response!

I do not have a scope that is working at the moment. I have an old Tectronix that someday I might get around to trying to repair/figure out, but for now:

I injected a 2,000Hz signal in, hoping that's high enough since, according to the documentation, the crossover is 1,600Hz and got the following:

At 1/4" jack:
Good = 0.071 Vac
Bad = 0.046 Vac

At input of 2µF cap (just to confirm it was the same as at the jack):
Good = 0.071 Vac
Bad = 0.046 Vac

At output of 2µF cap:
Good = 0.015 Vac
Bad = 0 Vac !!!

At tweeter output:
Good = 0.015 Vac
Bad = 0 Vac !!!

So, unless I'm misunderstanding, this points the the 2µF cap as well?

[stoneattic]

Of course I cam find 2.2uf everywhere, but 2uf either cost me more in shipping or are really large. Will 2.2 be close enough?

[DrGonz78]

It will be fine. I would save money .