Hello, long time reader, newly minted member here.
My T775HD had been intermittently giving me Check DSP Board errors, finally getting to the point of no digital audio completely. I contacted NAD, and ordered an AM200z board, and Erich kindly emailed me the latest firmware installer. Pulled the unit out the cabinet, did a little maintenance while I was in there, and installed the new board. Once installed, I updated the firmware, and placed back into the rack. Set the unit back up with some settings I had jotted down from before, and was a reasonably happy camper. For about a day. At first, I had audio dropouts when using Dolby decoders, so I set everything up as PCM to see if it would work. At first, it did, but then the dropouts began to creep back in. No rhyme or reason, no specific device, and no set length of time before it would happen. Then, the Check DSP Board message returned. Decided to reinstall the firmware. While doing so, I noted that it could not detect the DSP and UART firmware versions. Proceeded with the update, message returned as successful. Power cycled the AVR, the Check DSP Board message was back. Started the update software again, and once again it could not detect the DSP and UART firmware versions. Contacted Erich at NAD again, explained what was happening, and attached the install log for review. There response was to take it in for service. Thought I'd toss this out here, and see if anyone had any thoughts. If possible, I'd also like to find a copy of the service manual for it. At this point, I'm not real keen to spend a ton more on the unit, but I really do enjoy the sound of it. The Marantz SR5012 that's currently filling it's slot is OK, but it definitely isn't the same.
Thanks for reading, and thanks in advance for any help you may be able to provide.