No Sound from FX Mini

[Starbase101]

I've connected up an FX Mini, Audio Amplifier, and speaker as shown in the attached schematic, but no sounds play when touching trigger inputs to ground. The sound files transferred just fine from the computer, and with the board connected I can play the sound files from the board through my computer speakers with the file browser. But after properly ejecting the "drive" and powering the circuit at 5V I see the flashing red LED when grounding a trigger pin but no sound is heard from the speaker. There appears to be a tiny volume adjuster on the amplifier board (WAY too tiny) and I've tried adjusting that but still no sound.

Schematic.jpg (259.38 KiB) Viewed 382 times

[Starbase101]

While the FX Mini is allegedly playing a sound (red LED is flashing) its output pins read 0V, so I'm wondering if I got a bad audio board? I tried resetting the board by momentarily grounding the RST pin, but still no output from it.

[adafruit_support_carter]

Please try the demo tracks from the ZIP file here:
https://learn.adafruit.com/adafruit-aud ... udio-files
It may be a file format issue. The sound board is fairly limited and wants a very specific file format. The ones in the ZIP are known to work and are good for testing.

[Starbase101]

The file format is WAV.

There is "not enough disk space" to load all the demo files onto the board, so I copied over just T01RAND0.wav. Again, when triggering the red LED comes on (for a longer duration this time, apparently the demo file is much longer than my file) but there is no sound at all coming from the speaker.

[adafruit_support_carter]

OK, seems like the file is at least playing. Let's check hardware. Please post a photo of your setup showing how everything is connected.

[Starbase101]

In the photo:
- Bottom power rail is 12VDC coming from an AC/DC power adaptor.
- Top rail is 5VDC from a 7805 voltage regulator on the left.
- Center is the 2342 FX Mini with 0.1uF ceramic and 47uF electrolytic capacitors across Vcc and Gnd.
- Rout is connected to A+ of PAM8302A on the right, and the speaker is 4445.

T1 is grounded (red LED is lit) but no sound at all is heard from the speaker.

Breadboard.JPG (657.83 KiB) Viewed 332 times

[adafruit_support_carter]

Thanks. Looks like your breadboard has split power rails. So the amp is not getting any power. Try jumpering here to connect the two upper rails so 5VDC (and GND) run the length of the breadboard:

jumper.jpg (102.22 KiB) Viewed 325 times

[Starbase101]

Thanks, good catch - but, the original breadboard I had this wired up on has no split rails and it didn't work, so I transferred just the Adafruit portion of the circuit to a different breadboard (for simplification and isolation) which apparently does have split rails. I added jumpers to connect the rails and still no sound from the speaker. I am measuring 5V across the amp's Vin and Gnd terminals:

Breadboard2.JPG (626.31 KiB) Viewed 321 times

There is 0V measured on the FX Mini's output while a sound is "playing":

Breadboard3.JPG (627.47 KiB) Viewed 321 times

[Starbase101]

Just for kicks I connected the amp's input to the FX board's Lout instead of Rout, in case maybe mono audio is output on L instead of R (not documented anywhere that I could see). Still no sound from the speaker and 0V measured on the output. I changed the multimeter's setting to mV and there is fluctuating small voltage variations on the output but still no sound from the speaker.

[adafruit_support_carter]

OK, let's check soldering next. Can you post some photos showing the soldering on the headers pins more close up. Let's focus on just the PAM8302 breakout for now.

[Starbase101]

There don't seem to be any soldering shorts.

PAM1.JPG (426.03 KiB) Viewed 278 times

PAM2.JPG (401.08 KiB) Viewed 278 times

[adafruit_support_carter]

Thanks, yah, that generally looks OK.

Do you have some other audio source that could be used to try and check if the amp is OK?

[Starbase101]

No just the Adafruit FX Mini board. When ordering I bought multiple copies of the FX board, amp, and speaker, so I guess I'll solder headers onto another set of boards and see if I'm still having issues. If one or both of these boards are bad then it doesn't seem probable that another pair would also be bad.

(I have "Notify me when a reply is posted" enabled, but I don't receive notifications for new replies.)

[adafruit_support_carter]

Oh, good, you have duplicate hardware. That will help. Yah, try first just soldering up another PAM amp.

[Starbase101]

I've got a bad amplifier board. Since I've got extras for both boards I went ahead and replaced both, and sound plays from the speaker. Next I replaced the FX Mini with the original board and sound still plays from the speaker. Then I replaced the PAM with the original board and now no sound again. Evidently the problem is with the PAM board. How do I go about getting a replacement?