Ez B V4 Audio Volume

 
#1

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.

#2

If you can hear the audio a little, then i would test your amp

If the amp is indeed working, then check the wiring

#3

I have tested my external amp using both my phone and my laptop, the amp works fine, when I connect my EZ b the audio is very quiet. Not only that when I try to use the on board speaker and amp that is in the ez b I can only hear it if I put it right next to my ear, since it is so quiet. I've made sure that the springs on the speaker are connected properly and still no difference

#4

Where did you connect the external amp to the ezb? Did you connect the amp to the speaker terminals?

#5

User-inserted image

I connected the audio here and to the ground on the upper right, the one in the center labeled GND

#6

Check the solder connection to see if the heat melted through the surrounding protective layer and is causing a short to ground. A continuity test with a electronic meter will help.

#7

I do not think that it is an issue with the external connection, that system works fine when connected to something else. I did a continuity check on the connections I made and everything seems to be alright there. Even without my external setup the ez b itself seems to have no volume to it, like its getting a bad connection to the speaker but from what I can tell it is making a good connection. I work for an electrical engineer so I know what is going on for the most part, whatever the issue is it seems to be something with the v4 unit itself, what that is I do not know. When I hit the reset button on the V4 I can barely hear the voice telling me what is happening. As of the first post I made I had completely disconnected my leads and reverted it back to as I had never modified it in the first place.

#8

Please check the solder connection on the ezb to ensure it has not melted the nearby ground shield and shorted. You can use a multimeter for the test.

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.

#9

As @DJ mentioned, it could be that there's a short somewhere. Please test the audio input pad to Ground, if the audio input pin is isolated it should read in the 3 MegaOhm range. I suspect that the EZ-Bv4 processor or the audio amplifier chip has somehow been damaged, through static build up or otherwise, and is pulling down the audio. Unless the volume in the EZ-B soundboard control is just turned all the way down.

#10

happy jspinski, this sucks. I really can't help much other than offering moral support. I have to agree that you may have splashed a little solder over to an adjacent trace and caused a short. If you can find that short you may be able to clean it off and fix the problem if permanent damage hasn't happened.

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. Winky

Good luck! Smile