42" Sanyo dp42821 has fuzzy sound. Tried external USB/3.5 audio jack and it didn't cut out the internal speaker or any sound out of the external. External speakers OK on laptop.

The headphone jack needs to be replaced. Sound gets switched from speakers to headphone there. When the headphone plug is removed from the tablet the connection inside the jack is lost.

You have to check the audio settings of your tv. There would be n option which allow you to choose the option between internal speakers or external speaker. You have to choose it as external speakers of amplifier.
If you wish to get some more details then check the following link
http://electro-medical.blogspot.com/

Make sure you are connecting to the TV's audio-OUT jacks, not the audio-IN jacks. Also, check the TV options menu. Some TVs have a choice of internal or external speakers and you have to select one or the other; obviously, you would select "external".
On the soundbar make sure you have selected the correct input jack for the audio cable.

great post a Viewsonic with sound , none of mine have it.
2007 monitor old, most are dead now.
I hate those dinky shrill speakers inside.
NO PC told (a nebular Laptop)
no OS told
but windows has a sound mixer that allows me to pick 4 or more sound output devices, 1 at a time not all at once.
well when you connect the external speakers to any PC
3.5mm phone jack outputs, that switch in that jack cuts the sound inside the laptop dead BY DESIGN.
why would you want trash shrill speakers inside the laptop with
super find sounding external speakers at the same time.
trash + great sound = trash. why want this??? no body does.
nor if you plug in head phones to same jack the same thing happens speakers go dead, for privacy, (you and the others around)
lets see
external speakers not told, usb or 3.5mm phone plugs.
headphones USB or 3.5mm or both>?
and the View sonic has speakers? let me look now.
the manual shows
(stereo mini jack, for VX2450wm-LED only<<< got this?
the manual shows 3.5mm mini audio in jack
this means this opted monitor as amplified speakers inside
and when connected to phones on any laptop the laptop for sure has its internal speakers muted,

NO textual speakers told. besides monitors
all external speakers must have and amp , audio power amp
or the speaker are dead.
the phone jacks NOT drive any raw wired speakers ever.
same with desktop green rear jack is line out or phones.
not raw spearks
if you do have AMP speaker it needs to have power to run..
AC or DC power packs.
the amp must be good, some old ones are not.
it must amplified the sound to the actual speakers.
the switch in the 3.5mm phones jack is hardware
and disables the internal LAP speakers by Design.
make sure the sound mixer is set to the correct output;.\
seen here

https://www.pcdied.com/no-sound/bluetooth-speakers.jpg

if you have sound from the headphone jack the sound circuit is good--audio headphone jack when inserted cuts off internal speakers--it could be 3 days old and have a problem with the jack.

before attempting that:

Look in set menu to see if speakers are switched ON or OFF.

Check on SET and a Box if used that sound is not turned off or low.

If set has hookup for external speakers is external or internal selected.

Does the set have sound when a DVD etc. is connected via one of the rear sets of audio/video input jacks?

SD TECH

if there are jacks in the back of your sanyo you can hook up 2 speakers if your sanyo do not have external audio RCA jacks for speakers...you will need a home entertainment receiver to hook up the 2 -7 speakers...

Extra speakers without having the external speaker jacks in the rear is definitely a NO NO. The surround sound is used by connecting the RCA jacks from the TV that say Audio Out to the surround sound audio input on the receiver.. The RCA cables are cheap, you can get them at Home Depot ect....

Internal sound board/amp is probably bad. But make sure that the speakers were not turned off in the sound settings menu for the television. You could try hooking up and external reciever to the audio output jacks of the TV and see if you get any audio from there. If you do at least you can still get sound from your tv...even though it is not from the internal speakers.

You shouldn't need anything plugged into the accessory jacks to get local sound from your set. Go through the main setup menu and check audio settings; they may be set to turn off the internal speakers to send the sound to a home theatre that you apparently don't have. Most sets have that as a selection and supply L-R audio for an external system and mute the internal speakers.
FYI: The three connectors you mention are coded as follows:
Red - right channel audio White - left channel audio Yellow - composite video (contains synchronization signals and video)
These may be input connectors (for external VCR/DVD decks) so check your owner's guide to verify.