[SiriusHardware]

Ah, there you go, right near the limit of an original 7805, probably too much for one to handle continuously unless mounted on a huge heatsink.

Sam, if you can draw ~ 1A from the output of the 5V rail without it sinking by any significant amount or looking like the teeth of a saw, then you're doing well.

Any ripple that there is ought to be high frequency, up in the high audio / ultrasonic frequency range since this is a switching type regulator. If you see low frequency ripple on the output you may have a problem with the bridge D1-D4 or smoothing (C9) on the input to the 5V regulator, although that would be making the output from the 12V rail rough as well.

Also worth checking that neither L1 / L2 have gone high resistance, and the same goes for both sides / sections of the power switch, one half of which switches the AC input to the positive supplies, the other half of which switches the AC input to the -Ve supply.