Samstag, 18. April 2015

Quirks with YET-M1 and USB-Ports

A few days ago, I ordered a YET-M1 Bluetooth Audio Adapter for just a few bucks on ebay. It has a 3.5 mm jack as audio output, you can simply hook it up to any active speaker and make it bluetooth enabled. It can so play the music from your phone wirelessly. It is powered over the USB-plug on the other end, so you just need to plug it in your phone charger.

Well, then I tried it out with an AV receiver, which even has a convenient USB port for flash drives already build in. However, the bluetooth adapter seemed like it didn't power up. The same happened with another hi-fi system's USB port. However, when powered with a phone charger or by directly applying 5V to the GND and +5V lines of the USB plug, it worked. My first guess was, that those USB ports don't output enough power for the adapter. This was easily disproved by being able to charge my phone over this port. I measured the voltage on the two power lines: 5V. So this should be alright.
Apparently it had something to do with the data lines. I opened the adapter to have a look at those and indeed, they where connected to the bluetooth chip. Maybe for configuration/programming in the factory. It seemed like this is is what pees on the parade. The AV receiver tries to communicate with the adapter and thereby freezes it.
Unsoldering the plug and bending over the data lines to disconnect them is what fixes the problem.
<s> Is that really what the manufacturer expects us to do? </s>

- Marv


  1. I tested one on a Samsung TV, plugged to the USB and the audio out to the A/V RCA but the TV don't see it. I will try to disconnect the data pins as suggested. Thanks

  2. I have the same Bluetooth adapter. What I don't like about it is the "auto-off" feature. After 45 seconds of inactivity, it goes into low-power mode and produces a very loud buzzing at the audio output. After another 45 seconds, it shuts down and requires re-pairing to work again. Has anybody figured out a way to disable this?