Question about the sound card.

[Garrette63]

I have everything working on the MintyPi so far except for the sound. I don't currently have it connected to the battery/charger and have been plugging it in to test it. I don't get any sound, and the volume level keeps resetting to 0, which means it's probably not detecting the sound card. The sound card is connected to the button pcb for power, and wired directly to a speaker for testing. Does the button pcb draw power from the Pi when the pi is plugged in normally, or is the sound card not getting power because it's not connected to the battery?

[Helder]

if the sound is going to zero in the Alsa Mixer then there is a software issue I recommend reburning the SD card image. So you have soldered the USB wires from the pi to the usb sound card? and what are you using to power the sound card? I know you said the button pcb but where on the button pcb? Pictures help.

[Garrette63]

I'll see if I can get some pictures. I have the second and third pins on the sound card going to the usb contacts on the Pi itself, and two outer pins going to vcc and ground on the button pcb. The other end of the sound card is connected directly to the speaker for now. I can try reflashing the sd card. Can I upload images directly to the forums, or would imgur be best?

[Helder]

Either one will work for image uploads.

[Garrette63]

I couldn't seem to get clear close up pictures with my phone camera. I checked continuity, and connections seem to be fine. I get a short when I check the connections to the speaker, but I assume it's because it's mono.

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[Helder]

Wiring looks ok but I would check the usb wires on the Pi are not touching GND (the one on the right side is always too close to a GND hole). Next is use a multimeter to be sure that there is 5v at the VCC and GND pads you have the wires connected to the usb card.

You might have a bad GND or 5V to the GPIO (GND is harder to get a good connection on the gpio) and to be sure of the GND the GPIO below the A button GPIO is a GND so also solder that one to be sure.

[Garrette63]

Did some more testing. Soldered the hole beneath the A button and tested for ground continuity. Seems to be fine. Checked VCC and GND for voltage and I am getting 5v on it. Also checked that the sound card is getting the 5v, and it is. Checked for a short to ground at the two usb points and it doesn't seem like there is one, and neither point is bridged with the ground points nearby. I can't seem to get any sound at all, still. The setting menu in emulation station defaults to PCM as the audio device and has volume around 75% or so. I can change it to master or speaker but neither gives sound and switching resets the volume level to 0 for every device.

Thanks for all of your help so far, I'm not really sure what it could be.

Edit: I SSH'd into the pi zero and used lsusb to check the devices and it shows "Bus 001 Device 002: ID 08bb:2704 Texas Instruments Audio Codec". Is that the sound card?

Edit 2: Okay, I found out that if I put my ear right up to the speaker then I can just barely hear game sounds when a game is running. Anyone have any idea why it would be so quiet or why my sound settings don't properly save?

Edit 3: I'm testing without the shoulder buttons being soldered on yet, just to make the board more easy to move around. Is it possible that my issues are from not being able to access the scripted volume control?

Edit 4: Setup the mode switch and the volume is maxed out, but the speaker is still extremely quiet.

[Helder]

Try a fresh reimage of the mintyPi v4 and also just use one channel of the audio output to see if that helps then if it works out solder that other wire back. Seems it's a software issue as I've had this happen once too and had to redo the image on the SD card, while your at it make sure the mode button and Left/Right are not grounded.

[Garrette63]

Thanks for your continued help.

I reflashed the card with a fresh image and I'm still having the same problem. The mode button is also working perfectly. I'm going to try messing around with alsamixer today.

Edit: I desoldered the bridge that merged both channels into mono and it fixed my volume issue. Any idea what might cause that or how I can properly merge both channels without ruining the volume?

[Helder]

you could try to use a small value resistor like 10 ohms and solder one to each output point so left and right go to the resistor (1 in each channel) then join them both to the speaker, kind of like a Y.