Update: I've taken the minidsp apart the chip is the XMOS 16L7C10, the ifi is a XMOS 8U6C5.
Update: I should add I have a DMM, oscilloscopes (Rigol digital and Tek analogue) and some other bits and bobs, my scope skills are amateur.
Hi,
This is the sequel to the hugely unsuccessful
https://www.eevblog.com/forum/beginners/borked-usb-connector-advice/.
The ifi went into the too hard basket.
And then a few days ago I start a multichannel audio project and grab my MiniDSP U-DAC8, pretty lightly used and been in storage for a couple of years, exactly the same issue as the ifi, I swear I'm cursed.
In addition to evaluating why I have so much stuff in my spares bin, I'm also starting to think this culprit is XMOS.
The XMOS chips in the ifi and minidsp are the same vintage circa 2014-2016.
I just can't see how this is a driver issue, Mac, Windows and Linux all show the same behaviour, the USB device is just not detected.
I swear I saw the minidsp show up once on the mac yesterday and it worked on the mac when I first tried it a few days ago. I can remember the ifi was (very) occasionally detected as well.
The times when I get detections seem to be on the first connect after the DAC has been unplugged and dormant for days and after that connect, if I unplug it and plug it in again I get nothing.
I've tried lots of different cables.
The ifi works fine through SPDIF.
I'm starting to think that it could be something like flash degradation on the XMOS, a bad "batch" of capacitors, electromigration, planned obsolescence or solar radiation for crying out loud.
I'm thinking of going deep on this one, the second DAC broke the camels back.
Where to start, these things are USB 2.0 and I'm happy to spend couple of hundred bucks to get bits that will help me troubleshoot this because it will be a learning experience?
Or the XMOS DACs could be fine and I'm doing something wrong but I've never come across anything like that, something I'm using could be killing them perhaps?
Please help, I've just learned bits and bobs about electronics using the internet, my background is IT.
Thanks!