?

Log in

No account? Create an account
home theater question - if you can't be witty, then at least be bombastic [entries|archive|friends|userinfo]
kyle cassidy

[ website | My Website ]
[ userinfo | livejournal userinfo ]
[ archive | journal archive ]

home theater question [Sep. 8th, 2011|10:14 pm]
kyle cassidy
[mood |hopefulhopeful]
[music |the right channel of Iron Butterfly's greatest hits]

If you're not an AV-club geek, you can just skip this and get on with your friends page.

We've got a persistent and annoying problem with our home theater which consists of:

A Yamaha rx-v440 receiver
2 Boston Acoustic vr20's in the front
2 Boston Acoustic CR55's in the rear channel
A JBL something-or-other center channel
A 40 watt powered subwoofer which isn't connected because when we watch Master and Commander it knocks things off the walls.

When watching a DVD or listening to a CD there will occasionally be a "POP" and the left speaker will go out, this will happen at seemingly random times, but often within 5 minutes of turning on the stereo. If I disconnect the cable and tap the terminal, it'll crackle as you touch the terminal, but no audio comes through.

If I power down the amp and turn it back on, the left channel will usually come back.

And occasionally the amp will just shut itself down -- usually at a very critical moment in The West Wing. The longest it seems the amp goes without shutting down is probably an hour.

I figured it was a short in the speaker wire, so I unplugged the left speaker completely, but the amp will still shut itself off. The vents on top aren't obstructed and we have a fan up there just in case, but it seems to have no effect.

Any ideas?
linkReply

Comments:
[User Picture]From: sr_smith
2011-09-09 03:22 am (UTC)
Sounds like the receiver is on its way out. May be a defective component in the amp, or an overload at some point (lighting strike) or brownout has caused damage. Any chance the receiver is under warranty?

You could switch the left and right speaker wires to make sure the problem stays with the left output on the receiver and doesn't follow the speaker - that will eliminate the speakers. If the receiver's plug has a ground pin on it, make sure you're plugged into an outlet with a good ground. If you're not sure, run an extension cord into the kitchen or the bathroom if there's a GFI and see if that has any effect.
(Reply) (Thread)
[User Picture]From: zebrallama
2011-09-09 03:36 am (UTC)
+1
(Reply) (Parent) (Thread)
[User Picture]From: nrawling
2011-09-09 01:06 pm (UTC)
My guess would be it has separate power transistors for the different channels, and the one that controls the left channel is blown/failing. I don't have a lot of experience with A/V equipment, but I've seen that kind of stuff in radio equipement quite a few times. A shorted speaker wire could have caused the damage, but replacing the wire isn't going to bring the amp back to life.

Swapping the speakers to see if it follows the channel or the speaker is a good idea. It might also blow the other channel if the wire or speaker is still shorting, though. Since the receiver is already damaged, it would be worth it to me to eliminate the speaker as the problem.
(Reply) (Parent) (Thread)
[User Picture]From: mrmeval
2011-09-10 01:00 am (UTC)
What are you disconnecting specifically? What are you tapping?

It sounds as if a problem with the receiver's output is shutting down the one output, possibly a bad connection. A bad connection can if it cycles often enough cause the whole output section to trip the safety system. The safety system is to prevent catastrophic failure and protect your expensive speaker system. Unlike many 1970s receivers you will not have it burn holes through the fiberglass laminate printed circuit board and blow the cones out of the speakers across the room.

My last brush with Yamaha was in the 90s when a company I was employed at serviced them as an independent warranty center. They did not skimp on treating their independent servicers well. They would in many cases extend the customers warranty if it was 'a little out of warranty'. Call and ask.

If you decide to have the receive checked out ask Yamaha for their top rated servicer in your area. Unfortunately many companies have stopped their independent warranty service program and have the units shipped to them. If there is a service center they may do in home service but for audio systems that would be verify the wiring is ok and take it into the shop.



(Reply) (Parent) (Thread)
[User Picture]From: badger
2011-09-09 04:05 am (UTC)

The Yamaha is failing. Given replace versus estimated repair on receivers in that range, I'd go shopping.

(Reply) (Thread)
[User Picture]From: mrmeval
2011-09-10 01:10 am (UTC)
It is a sad fact that it's cheaper to fill a landfill with toxic waste and buy a new one rather than fix or re-purpose the item.
(Reply) (Parent) (Thread)
[User Picture]From: mattcaron
2011-09-15 09:07 pm (UTC)
If it makes you feel any better:

My first receiver was a cheap Kenwood. Remote control stopped working. Whipped out soldering iron and fixed bad solder joint on IR sensor. Worked for another 4 years.

Video board went. Bought a Denon. Kenwood went in the closet.

Denon failed after three months. Sent for refurb. Twice. Now works (and has, for two years).

Started playing video games again. Dug out Kenwood. It now powers an audio-only 5.1 surround sound for playing Bad Company 2.

So, I tend to not throw things away if I can avoid it.

The problem is harder with computers - a $200 AMD Fusion CPU is both more powerful and more power efficient than dual-core rigs with high-end video cards from 5 years ago... So, those do get scrapped.
(Reply) (Parent) (Thread)
[User Picture]From: mrmeval
2011-09-16 12:13 am (UTC)
I'm torn between fixing usable things and tearing enviroterrorists to shreds so feeling better sometimes requires blood.

...and good for you. 99.99 percent of the human race would drool and short something out. My labor rate is $125/hr unless it's my days off then it's $2100/hr with a 5 hour minimum. I've been paid the second rate to fix some bank schmucks TV on a Saturday at 1am because the stupidbowl was Sunday. As long as the stupid are around I shall feed upon them.
(Reply) (Parent) (Thread)
[User Picture]From: mattcaron
2011-09-16 12:26 am (UTC)
I find that enviroterrorists can be suitably annoyed with immensely overpowered sports cars.

And yeah, the wife and I are both programmer/engineer types so we do a lot of fix it ourselves, grow our own food, etc. sort of things. Both of our cars have 100k+ miles on them, and we now have a garage, so we just keep fixing them and keeping things going.
(Reply) (Parent) (Thread)
[User Picture]From: yagathai
2011-09-09 06:45 am (UTC)
I would guess you've got a faulty capacitor or overheating component somewhere in your receiver. I don't know much about A/V setups but if that were a computer and you described that behavior to me, those would be my first guesses.

Does the amp come back up after you reset it?
(Reply) (Thread)
[User Picture]From: rhino_mittens
2011-09-10 09:14 pm (UTC)
Having had my rockstar sound engineer other half glance over your post in passing whilst he was passing me a beer; he says it sounds very much like you have dry joints on either the input or the speaker terminals inside the amplifier. This can be fixed by getting handy with a soldering iron to make sure the joints are firmly and freshly attached.
We have had similar problems with our own set up recently. If this doesn't make sense then please pursue further communication and I'll have him type a reply instead of dictating from the kitchen :)
(Reply) (Thread)