
jspinski
I am having an issue with my V4 audio volume, I had the audio working fine, and I had used a breakout I saw from Dave S, since I am doing the same sort of project as him, it went from the Via out to an external amp which worked fine, then when I connected the external speaker to the amp it worked amazingly. Then I shutdown for the day by turning off the amp first and came back today and went to start up my EZb and all of the audio coming out of it is almost un-hearable. I tried all the mentioned here https://www.ez-robot.com/Community/Forum/Thread?threadId=8755 and nothing seemed to work.
If the amp is indeed working, then check the wiring
I connected the audio here and to the ground on the upper right, the one in the center labeled GND
The audio pin that you've connected to is direct to the DAC I/o of the stm32 arm CPU. If it was accidentally shorted, it may be damaged. However, since there's a little bit of audio coming through, I'm guessing the dac may be fine but it is shorted to ground at the pin on the ezb.
It is odd that everything worked nicely until you powered down. Also you've proven that your off board devices are still working and wired correctly. My gut tells me that some V4 ezb on board component has failed. I don't think this modification id done correctly and cleanly would overload any parts of a solidly working EZB. It's been done many times without issues. My mod is still working nicely years after.
I can only figure two scenarios; either you splashed a little solder and caused a short and a component on the V4 failed after being stressed out or a component just gave up the ghost.
I don't think you'll be able to fix this unless you can find a short and clear it "and" if no permanent damage has been done. You may have to invest in a new EZB. One risk of cobbling and modifying a product like an EZB is that you forever give up the right of replacing it under warranty. Weather you damaged it or not, when you take on a modification like this you need to ask yourself if you can afford to lose the cash you've already invested in it.
Good luck!