portable dvd player no sound when playing a dvd

[sony mavica]

hey guys so over a year ago there was a shop up the road from me having a 1 day sale and they had portable dvd players 8" for $29 so i decided to get up early and buy one so i got one took it home put a dvd in it to watch and it played fine but i got no sound so i thought the speakers where broken it had av in so i hooked my ps3 up to it and it worked fine and had sound

so i was not too bothered as i could use it to play my ps3 i put it away it the box till i had a tided my desk up and had room to set it up but its been over a year now and i have just got around to setting up the dvd player

now im asking would anybody know what could cause the problem of the dvd player no playing audio from the dvd?

[poot36]

So you get sound from the internal speakers when using it as a monitor (ie AV in) but no sound when the dvd is playing?  If so it could be the AV input output switching circuit or the audio DAC for the DVD side of the player.  What tools do you have to fix this?  I would recommend a oscilloscope and potentialy a SMD hot air rework tool.

[edy]

It could be even simpler than that. If the audio jack let's you hear sound, but the internal speakers don't work, maybe they just have a loose wire to them? Vibration or shock may have jiggled a wire loose. Or if the speakers are mounted to the flip-lid, moving the lid open and closed may have tugged a wire loose. Or if some liquid may have spilled on the DVD and got on the speaker?

Anyways, I'd open it up and check the wiring to the internal speakers and see if it is just a bad solder joint or broken wire.

NOTE:  I bought a brand new out-of-the-box DashCAM and the image on the LCD looked all messed up, wrong color, straight from the factory. At first I thought it was a software error, chip, etc.... Turns out it was a loose flat-flex that connected the LCD to the display board. I just opened the little connector, pushed the flatflex more snuggly and deeply into it, and then closed the connector tab and it works fine now! No solder required. It was just a simple physical connection that caused a completely messed up display, straight from the factory.