looking for tech support familiar with Accuphase in the San Francisco Bay area

sounds to me like something fried in the power supply section...

i would try rb electronics in redwood city or champlifier in alameda

both are quite competent hifi techs, long wait, not cheap, but they should be capable with accuphase stuff which i see as high grade non-exotic solid state amplification

perhaps ask the usa importer for accuphase who they have authorized as service and repair centers on the west coast?

I believe Nick Gowan at True Sound in Campbell is an authorized Accuphase tech.

@jjss49 @wrm57 Thank you following up with me, I appreciated! 

I switched my another amp in with same set up, and it did show warning message "Overcurrent" so I think it is the input impedance too low. guess I forget to match the dac, and amp after I upgraded my streaming DAC, finally it back to track, and works great again.