I received this Sunfire Cinema Grand Signature (type II) in for repair of a noise and hum issue. I replaced all of the capacitors and diodes in the power supply circuit, including those on the individual amplifier cards where they were mounted too close to power resistors and had discolored. This fixed the issues. The customer never came back to pick up the unit. I held on to it for over two years, then put it on consignment. It sat in consignment for another two years before a customer bought it. Within a month, the noise and hum problem is back. Noise: Slight buzzing sound, all speakers, with the power off; AC power plugged in, on "Auto", Slight Hum all channels when running. All output transistors check good with a DVM, all fuses are good, no burned parts or traces.
I have since retired from the repair business, but I would love to not lose all the time, effort and money I have invested in this unit.
Has anyone had a similar noise issue with their Sunfire Cinema Grand Signature? Please help.