[PLUG] Monitor... dead audio

[Tom]

Before replacing any parts, it may be worth to try to inject some audio
signal to the amp amplifier first .... there are other failure modes
possible such as PCB, capacitor, mixer/volume control, DAC, ...... 
In any case, when you get all the way here into the TV - you could even
explore integrating the whole R-Pi with an amplifier shield into the
thing wiring the speakers directly from the shield .... and a lot of
other possibilities when you are really determined and equiped with
soldering iron, osciloscope, ....
Tomas
On Sat, 2017-03-25 at 11:16 -0700, Galen Seitz wrote:
> On 03/25/17 10:48, Chuck Hast wrote:
> > Yes, I have tried both inputs, and zip. There is something wrong in
> > the
> > audio
> > path. I can feed another TV with the HDMI cable from the RPi and
> > get good
> > audio, so the issue is with the TV/Monitor. I can tell you this
> > much
> > Westinghouse
> > is useless, I sent them a note to the address given for such
> > issues, they
> > sent
> > me a USER manual which I had stated very clearly that I had. Then
> > they sent
> > me a 800 number, I called that, they told me they were going to
> > send it
> > right
> > out to me, they sent me a USER manual, called them and told them
> > that I
> > already had the USER manual, and that I needed the service manual,
> > guy told
> > me he did not have it, asked to talk to a manager and he hung up on
> > me.
> > 
> > Called back, got a chick, she pulled up the trouble ticket number
> > and put me
> > on hold, and never came back online. Whatabunchaputzes...
> > 
> > I have looked high and low for it, I am trying to go through the
> > FCC it has
> > a
> > FCC symbol on the back but no grantee code. So not sure what is
> > going on,
> > flat screen tv/monitors fall under part 15 because they radiate, so
> > they
> > have
> > to have gone through the radiation testing, unless the label is
> > boggus.
> > 
> > Once I can get the grantee I will KNOW who the actual manufacterer
> > is, and
> > I can try to go to them. Or FCC may have it on the site, I have got
> > diagrams
> > of devices off of the FCC site before.
> 
> I think there's a snowball's chance that you'll track down a manual.
> Actually I'd say there's a snowball's chance that a manual even
> exists,
> much less getting a hold of one.  Then there's the potential language
> issue.
> 
> Assuming you're comfortable working on this and know enough to stay
> away
> from the AC supply ... sorry, I should have noticed the call sign
> earlier.  That probably means what I'm about to suggest is what you
> would have done anyway.
> 
> Pull the rear cover.
> 
> Find the audio amp if you can.  Presumably it's an integrated class D
> amp.  Post the part number here if you find it.
> 
> Look for a datasheet.  If you can find one, consider that a minor
> miracle.
> 
> Feed an audio signal into the monitor.  My preference would be the
> 3.5
> mm jack.
> 
> Probe the audio amp, looking for the line level audio.  Check the
> supply
> pins too.
> 
> Discover that the amp is dead.
> 
> Order a replacement part.  This is where the major miracle occurs.
> 
> Replace the part and cross your fingers.
> 
> 
> galen