New Hum In my Onkyo TX-SR603X

MLZ

Recently I have noticed that when I turn on my 3 month old Onkyo TX603, at first it sounds fine, but as it warms (1 minute or so) up a hum develops in all speakers. (It has always felt hot, but I thought that was normal for a this receiver.) This happens for all inputs, even when I select a device which is off. (FYI: my speakers are Polk RM6800 5.1)

Should I return it for repair or something other type of trouble shooting I could do?

The first TX603 I purchased had to be returned to CC after a couple weeks when the left channels stopped working. Poor quality control

okiepolkie

what speakers are you using with it?

Skynut

Try grounding it.
It could be comming from the cable input to the t.v.
Try disconnecting the cable and see if that helps.
Either ground it or put a cheater plug in the mix.

MLZ

What is a "Cheater Plug"?

Skynut

MLZ wrote:

What is a "Cheater Plug"?

Ha, ha, ha. I had to ask the same question when this was recomended for my hum.
It is one of those plug adapters that allow you to plug a 3 prong grounded plug into a 2 prong non-grounded outlet.
In otherwords you plug your grounded appliance into the wall and it bypasses the ground.
This will tell you if you have a ground issue.
If all your system components are pluged in and none of them are grounded and you still have a hum then the problem is not the ground.

New amp now a hum

MLZ

Already had a "cheater" (I do not have grounded outlets in my 75 year old house) so I found an old 3-way tap which let me plug into it even though the plug was "fatter" on one side.

No change

So I just unplugged the coax cable into my Scientific-atlanta cable box - NO HUM

Thanks

Is there something I need so I can plug my TV cable back in?

Skynut

Put a ground lug on your cable line somewhere.

phoneisbusy

A ground loop breaker should fix that problem. RadioShack should have something like that available.

Good luck

Dave

MLZ wrote:

Already had a "cheater" (I do not have grounded outlets in my 75 year old house) so I found an old 3-way tap which let me plug into it even though the plug was "fatter" on one side.

No change

So I just unplugged the coax cable into my Scientific-atlanta cable box - NO HUM

Thanks

Is there something I need so I can plug my TV cable back in?

Dennis Gardner

This may sound weird, but go outside and water your ground stakes. As dry as we are in firey Oklahoma, the ground doesn't have enough moisture at the topsoil to conduct current and we lose electrical ground. If you don't have a ground lug on your cable line coming to your house, drop close to your electrical box if you can or you may create another loop.

MLZ

After a Googling Ground Fault found this site, http://www.dplay.com/tutorial/cablehum.html. So I went to Radio Shack and, for $9.00, purchased 2 300 ohm - 75 ohm matching transformers: one with a female center and 2 leads, the other with a male center and two screws, combined the 2, connected the cable and box and, viola, no hum.

Thanks for all your help. I learned alot.

Skynut

Sweet, glad you fixed it.
I would still recomend getting everything grounded for safety sake.

MLZ

Now I have noticed on several channels, bleed over and serious video quality degedation with my quick fix so I just ordered an "Ground Loop Isolator." I'll let you know if there is improvement

Skynut

(snoop voice) Groooooooooooooooooound it.

MLZ

Where do I go to learn how to “Groooooooooooooooooound it”, whatever "it" is?
Do I somehow attach a grounding wire to my power strip and on to a water pipe? Do I some how attach a grounding wire to my cable splitter? Do I just have an electrician replace the electric outlet or do I need to rewire my house?

FYI:
I am a newb who bought my first A/V receiver and speakers last fall. Only 3 weeks ago did I first notice the hum. Following the troubleshooting help I found here and elsewhere, I disconnected the cable coax into the cable box and the hum went away.
I live in a bungalow built in the early 30’s. My A/V receiver, TV, digital cable box and DVD changer (2 prong plugs all) are plugged into a power strip which is plugged into a cheater plug so it can plug into a 2 prong outlet.
My cable has 2 splitters outside: the first splits to a cable modem and another splitter which goes to 3 TVs. I do not see a ground connected to the cable splitters.

Skynut

You can ground the splitter usually. There should be a small screw on the side for attaching the ground wire. Attach the other end of the ground wire to a ground rod. You may find one near the main power panel to your house, you can add the new wire to that ground rod or to a water pipe that goes in the ground. I have heard varying reports about grounding to the gas main, I don't like this option for lightening strike reasons.
An electrician may be able to add a dedicated 20 amp outlet for you rig and he will instal the ground at that point but sometimes they are required to bring the rest of the room up to code.
Good luck.

thehaens@cox.net

If you have a power center, conditioner that has a grounding lug, (my monster power conditioner has one), you can simply plug all your components into it and if the component doesn't have the ground plug on it, then you can simply run a wire from the chasis of the component (via a screw), and connect it to the ground lug.

I did an install recently consisting of a vintage Nakamichi Pre/Amp CA-5, and we were getting a ground loop, which turned out to be his CDP. I connected a wire to the chasis of the CDP, and ran it to the ground lug on the Pre and that curbed the hum..

In my system I do the same, all components regardless of the power cable, has a wire running from chasis to the ground lug on the condtioner...

Scott

Skynut

Same here except when I got to the big screen there is no chasis. I ran the cable line through my power conditioner and the hum dissapeared.
The problem he has is no ground in his outlets which means nothing in his system is grounded. His ground is comming to his system through the cable line.

thehaens@cox.net

Ah, good point Sky, I have my TV on a separate circuit to eliminate any RF interf...

scott

Skynut

I did the same thing but when I hooked up the t.v. L/R output to my AVR my hum came back through the t.v. I had to ground the cable line to get it to go away.

MLZ

Well a friend, who also knows house wiring, came over and was able to replace the outlet. I was not there, but he said he was able to ground it, since my wiring all has a metal jacket covering it and he could ground to that.. And the hum is gone, video is better and I have a sack on no longer needed parts.

Thanks to all on this board for all the guidance. I learned a lot in a very short time.

Skynut

Stick around, there is more learning to come.