Sound from TV to receiver goes out shortly after selecting TV input

[mja745]

Background: I have a Phillips model 42PFL5332D/37 that I use as my bedroom TV. About a week ago the speakers went out on the TV such that the sound is very low and distorted. Not wanting to spend much to fix the problem for a TV I just use for the bedroom, I decided I would connect the TV to a very old receiver I had laying around which still works great. The receiver is a Pioneer SX-2800.

What I did:
I connected the TV's Digital Audio Out port to the Coaxial In port on a DAC (Insignia model NS-HZ313) using a digital coaxial audio cable and connected the DAC to the receiver using a stereo audio RCA cable. (Note that the TV does not have a digital optical audio out port, and that the TV is connected to the cable box via HDMI.) At first this resulted in loud static sound coming from the speakers connected to the receiver. Then I switched the audio output format from my cable box to PCM and the static sound was fixed.

The Issue:
When I first switch the TV input to the HDMI port that the cable box is connected to, the sound plays through the receiver just fine and sounds great. However, a few seconds after selecting the input on the TV, the sound to the receiver goes out completely, no static or anything. As a point of reference for the amount of time, this just happens to coincide with the amount of time the TV displays the input selection menu after stopping switching inputs, however I was able to figure out how to keep the menu up and the sound still goes out after that same amount of time.

Is there something different in the way the TV decodes the audio signal in the first few seconds of connection to a digital input device (i.e. my cable box) than after the initial connection is made? Any idea how to fix this issue?

 

[Natsukage]

Hello.

Can you test your receiver using the digital audio output directly from the Cable box? Or is the Cable box optical audio only? If you are directly connected to the Cable box and the sound cuts off after a minute, then the issue is probably the amp (receiver) (or the cable box).

You can always connect the RCA audio output from the cable box directly to your receiver, though you will have only sound from the Cable Box, and not from any other inputs.

 

[mja745]

Hello.

Can you test your receiver using the digital audio output directly from the Cable box? Or is the Cable box optical audio only? If you are directly connected to the Cable box and the sound cuts off after a minute, then the issue is probably the amp (receiver) (or the cable box).

You can always connect the RCA audio output from the cable box directly to your receiver, though you will have only sound from the Cable Box, and not from any other inputs.

Hi Natsukage, thanks for the quick response. The cable box is one of Comcast's new "peripheral" boxes that connect to the main cable box wirelessly. This cable box does not have a digital audio output port, optical audio output port nor RCA audio output ports. The only output ports on the cable box are the HDMI cable output to TV which is what I currently use to connect to the TV, and the coaxial (RG6?) cable output to TV, which I do not currently use. Also, I do not have any other inputs connected to this TV, so I am fine with only getting the cable sound from the receiver.

 

[Natsukage]

Okay then...

First, check that DAC. Is the switch on the side correctly set to Coaxial? If not, then switch it and recheck.

Next, given the amp is already on the vintage side, can you test the pioneer receiver on the FM radio and check if it cuts off after 1 minute? If it does, then the issue is with the receiver. Also try changing the input in the back of the receiver to another one.

After this, my only suggestion would be to either test the DAC with another source, such as a DVD or Blu-ray. If the signal cuts off on another source, then you need another DAC.

If it doesn't....your TV set might have a defective Digital audio control. This may be due to the same reason your audio is distorted on your speakers: either the amplifier is broken, or there's capacitors that are defective in the power supply or main boards.
If you are sure it is the TV set, then I would suggest something like this to solve any issue you have:
http/www.newegg.ca/Product/Product.aspx?Item=9SIA7WX3JJ9579
This audio extractor takes the audio signal from the HDMI and converts it to RCA, while still letting the HDMI signal pass through unaffected.

Hope you find your issue. ^^

 

[mja745]

Okay then...

First, check that DAC. Is the switch on the side correctly set to Coaxial? If not, then switch it and recheck.

Next, given the amp is already on the vintage side, can you test the pioneer receiver on the FM radio and check if it cuts off after 1 minute? If it does, then the issue is with the receiver. Also try changing the input in the back of the receiver to another one.

After this, my only suggestion would be to either test the DAC with another source, such as a DVD or Blu-ray. If the signal cuts off on another source, then you need another DAC.

If it doesn't....your TV set might have a defective Digital audio control. This may be due to the same reason your audio is distorted on your speakers: either the amplifier is broken, or there's capacitors that are defective in the power supply or main boards.
If you are sure it is the TV set, then I would suggest something like this to solve any issue you have:
http/www.newegg.ca/Product/Product.aspx?Item=9SIA7WX3JJ9579
This audio extractor takes the audio signal from the HDMI and converts it to RCA, while still letting the HDMI signal pass through unaffected.

Hope you find your issue. ^^

I definitely appreciate all of the possible causes and respective solutions. I can rule out the first two of these four, the DAC switch is in the correct position and the receiver plays sound from another source without cutting off. I will try the audio extractor once I get home from work tonight, but my only concern with this is that the TV's speakers do not produce clear sounds for the first few seconds and then get distorted, they are distorted as soon as I select the TV input while the sound from the receiver is clear.