Audio Receiver keeps turning off when "B" speakers turned on...says check wires, but they are fine?

Question

i have 2 sets of front speakers attached to my receiver, which has a built in speaker "A/B" switch. For some reason, if I turn the "B" speakers on, it sounds fine, but then my receiver will almost randomly switch off, i'm not sure if it does so with too much volume to the B speakers, or what. When I turn the receiver back on, it says "Check SP Wires", which I have. I notice the left "B" speaker, when both "B"'s are turned on, has less volume than the right, but when plugged in alone, it has full volume... I can't figure it out. Any suggestions on troubleshooting?

Answer 1

A) Disconnect the B speaker wires from the receiver. Then select A/B and fire up loud music.  If the receiver shuts off - there is an internal short inside the receiver. Time for a trip to the repair shop.

B) If A works fine, re-connect the "B" speaker wires at the receiver, but disconnect the speaker wires at the speakers.  Fire up loud music.  If the receiver shuts off - the wires have a short somewhere along it's length. Replace the wires.

C) If B works fine, connect up 1 of the "B" speakers, fire up loud music and see if the receiver shuts off.  If so - that speaker has an internal short.  If nothing shuts off, disconnect that speaker and hook up the other speaker and repeat the test.  Eventually you should find a 'bad' speaker that needs to be repaired or replaced.

One of these should help you narrow down the short.

Note: I had a similar problem with my "A" speakers. I investigated each end of the speaker wires and could see no shorts at all, but the receiver kept shutting off.

Before going to the shop, I cut the ends off of all 5 wires, stripped and re-attached. The problem went away.  Something was shorting, but I could not see it.

<EDIT>

"What should I do?"

You have a dangerous mix of generic speakers and computer speakers.  The computer speakers are low power devices designed to work with their own power supply (usually in the subwoofer).  The subwoofer also acts like a crossover so only the higher-frequency sounds (that dont take lots of power)  go to the computer speakers.

You hooked these up to full-range speaker outputs and I suspect you told the receiver these little plastic things were "LARGE" in the setup menu so it sends tons of current to them.

By trying to save money and re-use computer speakers you have created over-heat conditions which has caused your receiver to go into "PROTECT" mode to prevent it from burning itself out.

Get rid of those crappy computer speakers.  They are a danger to your receiver.

Get some monitor-style speakers from a real speaker company like "Boston", "Definitive", "Energy", "Polk", etc. Or find some used ones on Craigslist.  This will give you much better sound and be a lot safer.

Answer 2

Receivers tend to do that when there is a short in the speaker wiring...

Or, which might be likely here, a mismatched impedance.

If the speaker is shorted, or the "ohms" rating is too low, the receiver will shut off as a type of circuit protection.

That function protects the amp from burning up from not having enough load.

Check and make sure your speaker's impedance rating is within the amp's specs.

If that's not the problem, I'd run the speakers individually (which you seem to have done). Then if that doesn't lead you anywhere, hook both speakers to the "A" side and see if the receiver shuts off again.

If it does, then it's definitely a speaker issue.

All that of course assumes that the wires are good and haven't been smashed (causing a short) or anything.

Good Luck!

Answer 3

either Mismatch in speaker impedance at B

or

Amplifier is dying you have to get it repaired as when you increase the volume it draws more power from power supply unit which is unable to handle (could be one diode faulty) brings down DC power to amplifier and you find volume has gone down. so check for all the three possibilities ie  speaker Mismatch,  Power Supply unit of Amp and B channel IC of Amplifier

Answer 4

Check wire to see if they are terminated right, i.e. black to black- red to red. Some speaker cables have a white/colored stripe to identify which wire is which. So make sure that stripe wire matches the red termination points on  the  speakers through to the receiver. If your cables dont have the white/colored stripe then one wire will have and abrasive look and feel to the insulation which is the same function as a stripe; to identify. I hope this helps