M20K 252 with "black" instrument panel?

[kortopates]

1 minute ago, gsxrpilot said:

So would an ideal scenario be to just run #2 all the time and only turn on #1 if there's a failure of #2?  

We spent some time trying to troubleshoot the whine on #2 back when I first bought the plane. But we never solved it. I'd love to be able to. It's much improved (quieter) with the PMA450a audio panel, but it's still there. And really not any fun to listen to for any length of time.

Running both together provides the ideal situation so that #2 is absorbing the load and saving #1, but should #2 go off line, #1 is comes alive without any pilot action.

yeah, you have my sympathies on your #2 noise issue. Mine had just gotten much worse with the new panel, it was actually fine before the new panel work except for minor load meter fluctuation that began in the last couple years. But all the recent panel work back there led to more issues due to the delicate wiring with some chaffed wires and previous wire patches  not done properly to alternator circuity that goes there since all the shunts are located there including the new JPI EDM 900 shunt. So I really had to fix mine - my #2 was indicating 3x what it was really putting out. To be able to properly clean things up back there, we put a in new 50 pin circular connector so that we could remove that quarter panel entirely now and fix the wiring correctly. It had seen too much jury rigging over the years simply because there is virtually no access beyond the 4-5" you can pull it forward. But it would be hard to go to that much trouble if the only complaint was whining noise.