Fails to connect using 5V output from amp

[bernard23]

Not had any network connection issues when powered using thd supplied wall wart, but I've recently started using the USB 5V output on my yamaha A-S501 amp. That is only Live when using either coax or optical, so if means that the Pro Plus is powered off when not in use. However, it often fails to connect to my network, I get the flashing blue light, then back to solid white and repeat.
Works OK when I revert back to using separate power supply, but want to understand why it's not working powered from the amp.

 

[etto1968]

I have the same amp, the usb port delivers only 500 mA. My WiiM mini was not running stable with this (too less?) 500 mA.

 

[bernard23]

I have the same amp, the usb port delivers only 500 mA. My WiiM mini was not running stable with this (too less?) 500 mA.

OK that must be it. It worked the first time I tried it, but not thereafter. Oh well, pretty useless port on the Yamaha then