Hello,
I have a Yamaha receiver RX-V1200 with a stereo set up, not surround. The other day I was playing some music rather loud but nothing too loud that the receiver can handle. All of a sudden the receiver shut off. I turned the receiver back on and there was a message on the the display that said Check SP Wires.
The receiver has a built in system to protect it. That's why it kept shutting off. The trouble shooting guide said to check for loose wires and to see if any of them were touching. everything was fine. So I concluded that the receiver was damaged because every connection was correct and the impedence of the speakers was correct on the receiver.
I shelled out money for a new receiver and the same thing happened. I disconnected one speaker and turned the vol up and it shut off at a certain point. I disconnected that one and connected the other, turned up the volume and it did not shut off. I tested the same way on the other channel.
I concluded that one of my speakers is damaged. But I'm not 100% sure. Will a damaged speaker cause the protection circuitry to turn off the unit when the volume spikes or is turned up to a certain point?
Go out and buy a digital multi-meter and if you're not familiar with how to use one, read the manual. Disconnect the speaker wires from the receiver, set the meter to resistance on the x1 or Auto scale and connect one probe to each speakers' wires. Once you get a steady reading, disconnect the wires from each speaker and insert the probes into the binding posts or terminals to take a reading. Compare the readings with and without the wires. If you see a drastic difference, inspect every inch of the wires. If you have a cat or dog, make sure they haven't chewed on the wires. If they have been spliced, replace them with something nice, not too expensive.
If you see less than about 6 Ohms on an 8 Ohm speaker, leave the probes in the terminals and gently press on the cone (gently and symmetrically), listening for clicking, scraping or rubbing sounds. If you hear any of these, your woofer may have been damaged. If the resistance drops to zero, it definitely has problems but don't try to read it while it's moving- a coil that's immersed in a magnetic field will induce a voltage, which will make the meter's reading inaccurate since you're measuring resistance. If your speaker is rated at 4 Ohms and you see much less than 3 Ohms at rest, it probably has a problem. Most 8 Ohm speakers read about 6.0-6.6 Ohms and most 4 Ohms speakers read about 3.0 - 3.6 Ohms. What you're doing with the meter is checking the DC resistance- the meter puts out a low current DC voltage and the meter measures the drop in return voltage, then the internal calculator crunches the numbers to give you the resistance.
