Hello dear ted,
i’ve just luckily found an alice stancoil ad 62/3 and try it with an old rythm box, sound lovely.
But there is a big bass buzz out of the (echo) send output with level fluctuating. Earing it at-50db on the main output.
One of the microphone preamp seems to be out of order .
So i put the desk to an electronic technician, it seem to be the “aux” power supply but he ask me if i have an electric scheme of the desk, that i don’t have.
Perhaps would you have one scheme in your archive.
It would be easier to fix the problem.
It’s a shame when I can’t help…. this is one of those times.
I don’t have any circuit information for the AD62/3, this was a mixer that we made just before the 828.
Certainly the problem is a power supply one; from memory that mixer used a single rail 24 volt power supply. I would suggest to your tech that he replaces the whole power supply with a modern switch-mode type; these are readily available now and not expensive.