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Strangest problem I've ever had

Ok.
Bought a house.
Paid guy to run wires through the wall for a 3 point system.(too many obstacles & $$ for surround)

Have walls patched and painted. Moved in.
unpacked My Pride and joy B&K 7 channel.

system includes Onkyo sr705, HDMI from cable box to onkyo, connected polk rti12 speakers to B&K with bananas.

turned it all on, incredibly loud buzz snap crackle pop, onkyo shuts off and burnt wire smell fills the air.

Trouble shoot. all wires were hooked up right.
connect speaker wires directly to onkyo one at a time. the farthest one away in the wall shuts off onkyo. I run a new wire on the floor to that speaker. It works.

So it's the wire in the wall, it got compromised some how when the patched wall..?
not so fast.
I have an old kenwood preamp and adcom 2 channel. I hook up "bad wires" in wall directly to kenwood and the speaker works fine. how can bad wire short one amp and work on another???

So then I hook up an RCA pre out channel from the onkyo to the adcom and the same very loud buzz comes on the good speakers.

So the Pre outs on the Onkyo are definitely sending the buzz to both amps... can we assume the Onkyo pre outs are shot.
Million dollar question. Why does the line in the wall short out the onkyo but work on my old kenwood.

So then I test a good speaker line on each output on the onkyo. They all work... I'm doing this with it on, even though I know better... Then I went to connect the bad wires to the onkyo again and I got a spark when I connected the red wire...I've never seen a speaker wire spark off a preamp????!!!!
i've never seen that. I'm going to get a meter and read the line resistance and see if there is a difference with the bad wire.
My concern... If I go get a new preamp, can the bad speaker wire blow it again.
Makes no sense.
That wire was hooked up through the B&K. B&K was connected via RCAs to Onkyo. How could it short the onkyo going back through the B&K.
do we think the onkyo was toasted in the move. If so, how is it that just that 1 line shorts the onkyo and none of the others... too strange
riasillo

Showing 6 responses by riasillo

riasillo OP
12 posts
 
Thanks for responses.

On way to get a meter to test wires.
I do think the wire got compromised . Low volatage guy did his thing, then electrician did his, then sheet rock guys. Someone probably hit that wire...but I also think the onkyo pre outs are toasted.

If I hook up speaker to power amp and receiver to either of my amps from any pre out, plugged into different outlets with nothing else attached, volume on zero = very loud buzz... very loud... none of the pre outs are working right.independent of anything else attached.

like al said, it would seem there are 2 different problems present. I think the burnt smell came from the onkyo.

I used in the wall double coated monocable 12 aug.
I just can't wrap my head around a short in the speaker wire plugged into the power amp, back shorting the onkyo plugged into the Power amp with RCAs. is that possible? wouldn't you expect the power amp to go if anything?
also, if there is a short in the wire, how could the kenwood receiver work on that line. is that possible, like if that receiver doesn't have the same level of circuit protection...
riasillo OP
12 posts
 
so i tested with meter.
I dont have much experience with meters, tested some circuits at first job but it was always under direction.

Both set ups respond the same.
i had to crank up ohm resistance on meter to get a reading. First time around both pinged beyond zero...so cranked up resistance dial so reading was right in the middle on good set up. suspect wire, pinged middle.
both respond identical. the wire must be good...right?

2 settings x1k and x10. both respond same
except at x10 setting I hear static from speakers.
?
all other settings detect nada on either.
too bizare...that just that wire shorts out onkyo..

pre out from onkyo still shot..
off to buy a new receiver... open to other suggestions using meter.... anyone that lives in the Los angeles vetura county area and want a suspect onkyo sr705 to tinker with?
thanks to everyone for help
riasillo OP
12 posts
 
when i test the wires they read no resistance.
dial swings from infinity all the way to beyod 0 the second i complete the circuit. same as on the non suspect wires...

the wires in the wall are perfect as far as I can tell.

is there any way to test them with my kenwood amp running juice to the speakers so that I can see if under power they have a different reading? or a difference between speakers and wires.
riasillo OP
12 posts
 
Ding ding ding...
we have a winner.

Thanks to Al and MEtro04
I calibrated meter as per Als instructions, and touched the wires to AC cover screw as per metro.
red wire, the one that arked, reads 0 resistance..
black lead didn't move.

So red wire got nailed or screwed in wall.
and based on what metro said, that could have shorted my receiver input circuits... unreal...

live and learn, should have hired a better low voltage guy that properly protected the wires in the wall... I didn't like the way he left them exposed around studs... I should have covered them with some cheap metal strike plates...or he should have...that guy is getting reamed on Yelp.
riasillo OP
12 posts
 
jea 48.

low voltage guy passed wires around studs in the front between drywall.
I questioned it, not knowing any better and he said it was fine because the drywall guys could see it and work around it. Hard lesson learned.

also cost me a perfectly good receiver.

The electrician came in after, ran electric from existing bank of outlets to spot above fireplace for recessed outlet. His wiring went through studs and was to code as best I can tell... thick yellow wire, that's all I can tell you.

I also had everything plugged into APC line conditioner/surge protector.

Drilled hole today to outside of house, poked wire through and ran it under edge of house out of site, came back in where the cable wire comes. Problem solved ghetto style, I now have a left speaker run... just cost me a $10 for a masonry bit.

Hooked up speakers to onkyo direct, drives them fine... pre outs still shot.

Now i'm off to get a new receiver...what to buy, what to buy...
I was planning on plugging receiver into amp with nothing connected to receiver. fingers crossed when i plug into AMP that the B&K is fine and there is no buzz... then i will connect cable box to receiver and hopefully speakers sign again... any suggestions on way to test amp other than that?

I actually have a little Ipod 1/8jack to RCA adapter. I could plug that into amp and see if amp works right?
riasillo OP
12 posts
 
plugged Ipod into B&K. she sings... music to my ears...

thanks to everyone for help, trouble shooting, learning how to use a meter, etc etc... great community.. thanks again.
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