What's this yellow thing?

[DanOwens]

This PA speaker's not working so I put a multimeter on the white thing and the yellow thing and the little thing and the only one that seemed not to be working is the yellow thing. I guess that means if I replace it, it might work so... what the hell is it!?

Edited February 5, 2017 by DanOwens

[thebassman]

It's a capacitor, should have the values printed on it.
Cheers
Thebassman

[MoonBassAlpha]

Yes, a capacitor won't give you a reading on your multimeter like a resistor will. This is because a capacitor is 2 sheets of metal foil separated by a thin insulator, all rolled up into a cylinder. 1 foil sheet is connected to each leg.
Did you measure across the speaker whilst you had the meter out? Should measure slightly less than the value printed on the label.

[Phil Starr]

What is actually wrong with the Speaker? The capacitor is almost certainly being used to stop bass reaching the tweeter so if that was broken it would mean the bass unit would still work the white 22ohm resistor will be part of that circuit too. The coil is to stop treble going to the bass unit.

If nothing is working then the fault lies between the crossover and the amp or in the amp itself. Start off by checking your leads and then the sockets.

[Dan Dare]

[quote name='Phil Starr' timestamp='1486388511' post='3231303']
What is actually wrong with the Speaker? The capacitor is almost certainly being used to stop bass reaching the tweeter so if that was broken it would mean the bass unit would still work the white 22ohm resistor will be part of that circuit too. The coil is to stop treble going to the bass unit.

If nothing is working then the fault lies between the crossover and the amp or in the amp itself. Start off by checking your leads and then the sockets.
[/quote]

Phil's correct - probably a bad connection, although I don't think there is any "almost certainly" about the cap being used to prevent low frequencies from reaching the horn. It will be. That looks like a simple first order crossover with a resistor. As Moon says, a cap won't give you a reading like a resistor or an inductor will. If you have 2 PA speakers, try swapping the drivers between them and seeing if any have failed.

[Phil Starr]

[quote name='Dan Dare' timestamp='1486389020' post='3231309']
Phil's correct - probably a bad connection, although I don't think there is any "almost certainly" about the cap being used to prevent low frequencies from reaching the horn. It will be. That looks like a simple first order crossover with a resistor. As Moon says, a cap won't give you a reading like a resistor or an inductor will. If you have 2 PA speakers, try swapping the drivers between them and seeing if any have failed.
[/quote]

I think that's almost certainly right but it's such a basic crossover that it might just be a series circuit, though I haven't seen one of those for over 40 years. It would be very unlikely but I've seen very old crossovers where they used this to reduce the size of the inductor.

[DanOwens]

I got interrupted half way through my diagnosis, but I'll have another check of everything. Damn, I was hoping for an easy fix!

I'll return with more stupid questions!

[Bill Fitzmaurice]

If the cap was blown it would only affect the high frequencies.

[Happy Jack]

[quote name='DanOwens' timestamp='1486333532' post='3231005']
... the white thing and the yellow thing and the little thing ...
[/quote]

You sir are a man I could do business with.

[DanOwens]

So I put my multimeter on the two connections of the speaker and It's look like there's no connection.

-Does this rule out the circuit being the problem?
-Can I repair something in the speaker, or does it just need replacing?

Thanks

[Bill Fitzmaurice]

You've got a blown voice coil. An expert can re-cone the driver. Replacing the driver is an option, but the T/S specs and response must be the same as the original.

[DanOwens]

Thanks Bill. It's a generic Chinese thing but there's a code on the back so I'll do some digging.

[DanOwens]

So it seems the system (Meridian kp620m) is so generic that I can't find any details online. The speaker cone has 'cw 10/100 8Ω' on the back.

If i can't find the specs on the speaker, what happens if I replace it with any old 10", 100w, 8Ω speaker?

Thanks!

[Bill Fitzmaurice]

[quote name='DanOwens' timestamp='1488134609' post='3246192']
If i can't find the specs on the speaker, what happens if I replace it with any old 10", 100w, 8Ω speaker?
[/quote]Impossible to say. It may sound like utter crap, but that's pretty much a property of no-name Asian products anyway.