Check SP cables

[Paul Beck]

I have a Yamaha home theatre system based around a RX-V640 amplifier. We have a 5 speaker setup located in our lounge plus 2 outside Nile patio speakers designed for outside use. There is no problem with the inside setup but when we switch the system to power the external speakers, if the volume is increased to around the 34db level the amplifier shuts down. On powering it back up the message check SP cable can be seen.
I have checked all leads to the speakers and even if they are disconnected the same thing will occur.

The setup is such that the internal speakers operate if speaker A is selected and the external speakers are selected using the speaker B option on the Amp. The shutdown occurs only with B (external) selected...it does not occur with the internal speakers and has only recently become an issue.

I cannot see a short on any of the connections....any ideas as to what is happening?

Many Thanks

Paul

 

[JohnnieB]

Hi Paul. You have figured out that "check SP" means check speaker cables. You also state that even with the speakers on B unhooked it still goes into shutdown. Is that unhooking them at the receiver or the speakers.
The receiver is seeing a short on the ch. B output. Depending on how or where the cables are run to the outside speakers you may not be able to effectively inspect them. IE if they are in a wall or ceiling.
I would hook your main L/R speakers up to ch. B and see if the problem remains. If so, I'd say your Yammy went kablammy. At least on ch. B.
If the problem does not persist, its your wiring or your outside speakers.
At which point, take the outside speakers in and hook them up to ch. A. If problem persists, its time for new speakers. If it plays fine, time to run new cable.
Good luck. Let us know what you find.

 

[markw]

Good advice above but a quick check would be to disconnect the "B" speaker wires at the receiver. Then, if all is well, you should be able to select the "B" speakers and your amp should be fine.

That would pretty much isolate the problem to the wires to the patio speakers.

If it does shut down, then it's definitely the yammie.

 

[Rickster71]

What's the ohm rating of the speakers, what gauge wire and how long of a run?
Did you happen to disconnect the speaker wires with the amp powered on?

 

[Paul Beck]

Thanks to all for the advice. I am the process of running through some of the checks recommended but I have found one strange thing that may provide a clue as to what is going on. If I set the base on the amp to the neutral or mid setting I can then increase the volume of the patio speakers to approximately 26 db which is a lot higher than previously. (This was due to the fact that the bass had been set or left on at a high level which I had not noticed).

So if I now run those patio speakers at around a 26db level it will operate normally. But, if I then turn the bass up toward a higher level then the amp simply cuts out and you get the check SP cable message.

 

[JohnnieB]

Good find Paul. If your mains run on ch.B without issue, revert back to Ricksters post. You may be asking too much of the receiver to run a low impedance speaker on a long run with the bass boosted.