New Posts  All Forums:Forum Nav:

Alien Dac problem

post #1 of 4
1/11/10 at 11:43am
Thread Starter 
Hello.

I just finally finished my AlienDAC...well actually I finished all the soldering about a year ago but just yesterday I got to hook it up.
When plugging it in to any of my laptops, I first get greeted with the usual message about a USB device being plugged in the port.
Straight after it, I get a message that "A USB device has malfunctioned AND is not recognized by Windows"

I have no idea from where to start troubleshooting, I hope I haven't burned the PCM2702
Reply
post #2 of 4
1/11/10 at 12:02pm
Quote:
Originally Posted by DolbyR View Post
Hello.

I just finally finished my AlienDAC...well actually I finished all the soldering about a year ago but just yesterday I got to hook it up.
When plugging it in to any of my laptops, I first get greeted with the usual message about a USB device being plugged in the port.
Straight after it, I get a message that "A USB device has malfunctioned AND is not recognized by Windows"

I have no idea from where to start troubleshooting, I hope I haven't burned the PCM2702
First thing to do is check the 3V3 test point - do you get 3.3V? Typically, a USB connection malfunction is related to the digital end of the PCM chip, which is powered by that 3.3V connection.
Reply
post #3 of 4
1/30/10 at 8:25am
Thread Starter 
Thanks Tomb,

I was finally able to measure the voltages (my old dmm died, then no time, and so on..)

so..
Input to Alien (from Soha 12v points through lm317 reg) - 10.50v
5v test point - 5.42v
3.3v test point - 3.30v

so everything seems ok, right? Atleast in what concerns the voltages.
Reply
post #4 of 4
1/30/10 at 10:24am
Quote:
Originally Posted by DolbyR View Post
Thanks Tomb,

I was finally able to measure the voltages (my old dmm died, then no time, and so on..)

so..
Input to Alien (from Soha 12v points through lm317 reg) - 10.50v
5v test point - 5.42v
3.3v test point - 3.30v

so everything seems ok, right? Atleast in what concerns the voltages.
Hmm ... actually, the 5V test point usually was supposed to measure ~4.75V. The Alien had an option for external power to provide the 5V supply, but I believe you needed to use the BUF634 option to provide ground isolation with a virtual ground amp (the SOHA qualifies).

So, I'm not sure what you're doing with the 10.5V. That's way too much voltage for the REG101 to regulate, unless you're using the voltage and regulation simply from the 10.5 down to a ~5V, generally without a REG101.

The other requirement would be the use of the BUF634 to prevent a grounding conflict.

Finally, it may depend on your laptop. There were some early versions of VISTA - and it may have existed elsewhere - where the USB driver did not properly operate. There's a hot-fix available from Microsoft if your laptop OS falls into that category.

I would look at those things above and see if any of them apply to your situation.
Reply
New Posts  All Forums:Forum Nav:
  Return Home