There is a more permanent solution though if you’re uncomfortable with leaving the EEPROM in permanent RW mode. And that solution is to lift the WRITE leg of the EEPROM and turn that chip into READ ONLY mode - something Accuphase should have in the first place.
This mod means the Bravo chip will lose the capability of writing to the chip, thereby removing any chance of corruption down to 0%. This has its downsides though, we aren’t certain why the firmware is writable. Disabling this ‘feature’ may have unintended repurcussions - e.g. if this DAC is firmware upgradable this mod may potentially make it harder to upgrade.
Steve kindly performed this mod on my DAC, and I’m confident to say my DC-37 will not suffer the same affliction a second time.
So to summarise, the first generation DC-37:
- The EEPROM behind the USB receiver chip is erasable
- USB receiver (Bravo) is always powered by USB cable. So powering off the DC-37 from the mains will not power off the USB input
Combined, under rare conditions you can corrupt the USB receiver EEPROM. The solutioni:
- Lift the WRITE OK leg, and set the EEPROM permanently on READ ONLY mode.
Please share in the comment below if you have a DC-37 with a malfunctionig USB input, or know anybody who has one. Hopefully Accuphase has already addressed this in the later revisions. And if you have a problematic USB port, here’s the fix, and how to prevent it from happening again.
Comment from: Evgeny Visitor
Thanks you very much! I had the same issue with Accuphase DC-37 and your guide helped us to get the device back to work!
Happy to hear that. Was it a bad receiver or a corrupted EEPROM in your case?
Comment from: Clark Visitor
My device has the same problem. What model of EEPROM is replaced? Thank you.
You don’t replace the EEPROM per se, just need to reflash it with a working firmware and your DAC will be back working again.
Comment from: Eugene Visitor
Hi, Agent Kith. My name is Eugene and I think I have th same problem with DC-37 USB port. Windows cannot identify it, says "the USB device is not working proper" or something like this (please, exuse me for my english). Please, can you kindly help me - how can I reflash the usb port? I’m really stressed now, don’t know what to do…. Please help!
You need to reflash the EEPROM on your DAC. This is a electronic component inside the DAC and require a technician with specialist tools. Or you can replace the EEPROM with a working one meant for the Bravo chip.
You can check around your area and see if any audio technicians with the ability to do this. Send them this article for reference.
Comment from: Zinoviy Visitor
Hello, where can I get a firmware to reflash EEPROM with? Or get a working EEPROM chip?
Comment from: Clark Visitor
Successfully resolved! Thank you very much!