I've narrowed this down as far as I can go. I'm in the middle nowhere northern Wisconsin. I was Service Manager for Sequential Circuits back in the day, so I'm hoping to avoid a trip to a repair center. This machine has not been powered up in 4 or 5 years, but has now been running for a day or two. Doing final initialize and check out before sale.
Here's the scenario:
1) no connection to any input digital or analog. Only analog outputs 1 and 2 connected to board.
2) Using "Setup" screen, if I route anything to analog outputs 1 and 2, there is noise that I would associate with word clock (changes with sampling rate or digital input connection) The only way to eliminate it is to select the "
" (nothing) input or to select a digital input with no connection.
3) connecting an active digital input changes the character of the noises and introduces a slightly noise when I select the digital input.
4) no noise at all on outputs 3 and 4, in any configuration.
5) all inputs, outputs, and DSP units work fine except for this noise.
A bypass cap gone south somewhere? Any ideas? Long past warranty. No fear opening the box, have been there thousands of times. Would love to do this in the shop and avoid shipping or 300 miles of driving.