A little gem - The Yaorea YRG01 (Review & Mod)

Ugh, Ignore all of that.... The amp IC is powered all the time, whether on or off in the menu. Powered with USB I'm getting ~4.15v on pin 6 of the IC (VDD). I'll look some more and see if I find anything. It's hard to diagnose a faulty unit whne I only have a working one to play with. 

I have done a bit more digging but struggling to really work out how this amp IC works. What I have found is that the VDD (pin 6) is always powered with around 4.15v. This is smoothed by a couple of capacitors to the right of the IC. Pins 2 and 3 are connected together and go to one side of C44. The other connection on C44 is ground. Where Pins 2 and 3 connect to is not apparent. Looking at the datasheet it seems these go nowhere, except for that capacitor. When the clicker is turned on I get +2V on pins 2 and 3, and 0V when it is turned off. It seems something is enabling the IC, somewhere. Looking at the example in the datasheet it looks like pin 1 is enable. This is connected to the top pin on the little transistor/mosfet to the right of the amp IC. It is most likely that MOSFET that is turning the amp IC on and off. The other two pins on the MOSFET are ground and a pin on the MCU, likely a GPIO.

The audio input is on pin 4 of the amp IC. This is connected to R46 then C45, then goes to L12 at the left of the ribbon connection then to pin 3 of the ribbon cable. I'm numbering the from the left where PZ is printed on the board next to the ribbon connection. So working backwards the clicks audio comes over from pin 3 of the ribbon, into L12, then C45, then R46, then pin 4 of the IC.

You should expect to see ~4v on pin 6. Ground on pin 7. Pins 2 and 3 get ~2V when the clicks are turned on in the menu. Pin 1 is enable/disable and should get a high or low signal when the clicks are turned on and off. I don't know which way that is.

First things to check is do you have ~4V on pin 6. If so then do you have ~2V on pins 2 and 3 when the clicks are turned on. If all good then trace the audio path back over to the HV PSU board. If your ribbon cable soldering is anything like one of mine then it is suspect IMHO. Also, when you enable the clicks in the menu, do you hear any noise out of the speaker, as in noisy PSU type noise? If you are getting that when the clicks are on, then it is likely being powered.

The reason I have looked so much at this, is the amp IC should be almost impossible to blow up at the low voltages it is running at. The ~4V supply goes through a 2.2 ohm resistor that would take a little current off is something like the speaker outputs shorted. I find it hard to believe the IC is dead.

To look into this more I would need more time, like half a day or something and get the board under the microscope so I can trace it all out properly. Where are you? Not in the UK by any chance?