Audio amplifier off

#1

The audio of the proffieboard suddenly stopped working. It has worked before and suddenly it seems to be dead.

In the Arduino monitor it says that the audio amplifier is off.

Is it possible that the audio board is dead? Or is it something software related?

-speaker and connections work

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#2

Serial Monitor will show Audio Amplifier off when sounds stop playing. That doesn’t indicate a problem.
Some things to start troubleshooting:

  • You can type set_volume 1000 for example to make sure your volume isn’t all the way down.
  • You can measure AC voltage at the speaker terminals when sound should be playing to see if the speaker is bad.
  • You can measure for 5v at the 5v pad to see if the booster is bad.
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#3

I’ve done the trouble shooting. These are the result;

  • Set-volume 1000 didn’t help
  • The AC voltage whilst clashing is 0.2V at max
  • The 5V pad gives a voltage of around 0.4V
  • As indicated before, the speaker works fine on another proffie board

I reckon that means the booster is blown. Now since I have never smd soldered before, I was wondering if it would work to hook a 5V booster up from the battery to the 5V pad (and GND) on the board? Is this possible, or would this damage other components?

#4

Something like this:

#5

Backfeeding 5V may work but I do not know what the other pins besides the 5V output from the booster do.
Also, if the booster were the only problem, you would still have some audio, it would just be low power and sound distorted with volumes above something like 200-300 (like when the board only has USB power).
You may have cooked the amp as well (the U1 chip).

#6

Also, 480mA might not be enough to drive the amplifier, resulting in poor audio.
The traditional fix for this problem is to bridge the BATT+ and 5V pads, but you loose some volume by doing that.

#7

I’ve tried bridging the 5v and BATT+
This sadly didn’t help. So my amp must indeed be blown, is there any way to tap into the i2s to use a separate amp?

#8

A blown amp wouldn’t explain this.
Unless of course you measured the 5v pad when the saber was not playing sound?
(The 5v booster is turned off when not needed.)

Although, I suppose it’s possible for the amp to break in a way that turns it into a short, which could, in theory, explain it…

#9

Is it possible to send it somewhere to check / fix the board ?
Or are we supposed to buy a new one ?

#10

I could take a look into repairing it for you. I have a bunch of other evaluations/repairs on my bench, might as well add one more.