Reset tx-sv343 left and right speakers work when they want to.

Your (5.1) receiver supports just 6 speakers. Left, Center, Right, Left Surround, Right Surround and Subwoofer.
http://redirect.onkyousa.com/redirect.cfm?type=own_manuals&file=TX-SR304_En_0124.pdf

Could be the IC that controls the various sound/surround channel modes. Had that happen on my Pioneer receiver.
Charged me close to 200 bucks to fix!

i'm assuming you are using the red white yellow rca cables. plug one side of the cables to the out on the dvd player to the video in on the receiver. make sure you match the colors. video out from the receiver will go to the video in on the tv. make sure you set the source to whatever you plugged in on the receiver. if you plugged the dvd into video 1 make sure video 1 is selected as the source on the receiver. on the TV make sure you select the right source as well.

If you are convinced the left channel is out, and have tried using the speaker B outputs with your front spkrs. to see if the left channel works or not.....i would suggest getting a new receiver. You would have a new receiver with a some sort of warranty, and an option to buy extended protection. Unless there is a sentimental value for you..then keep it and get an estimate. Hope this is helpful.

there is an internal shorting inside the amp that puts the amp in protect mode also check if the amp comes on after disconnecting the speakers

I would be checking the set up mode , you might have it set to left or right channel only , but in mono mode both speakers will come on through one channel

Solution to having no sound coming from certain speakers in a 7.1 speaker setup for TX-SR606 receiver when playing a DVD.

Review the cable setup for the DVD player since it was identified as the source of the problem. Best to unplug and plug in the cables to ensure they contact the back of the receiver's RCA jacks. Redo the microphone setup for Audyssey 2EQ calibration. A good chance that it is the cable that may have caused the malfunction and loss of sound from the speakers. The cables can come loose during setup and not plugged all the way to the back of the RCA jacks or a defective cable causing signal loss.

Greg- Powered subs are better than non-powered subs (also known as passive subs), anyway I see the TX-8511 has no sub pre-out on the back panel, so you need to decide what sub you will use and run from the receivers left and right speakers output into a subwoofers speaker in from speakers then back out to speakers, look at the back of a subwoofer and you will see like 4 sets of speaker hookups 2 in and 2 out, what this does is takes the low end or bass and drops the signal to the subwoofer then takes the mids and highs out to your left and right speakers, unless your regular left and right stereo speakers have large woofers a sub is the way to go.

SOUNDS LIKE HE HIT YOUR SPEAKER CHANELS 1 OR 2,,, PUSH 1

did you swap the left from speaker with the left front?
if still crackels after that them you have bad left output.