The band that I've been working with for the past year
uses a Mackie PPM1012 powered mixer.

They bought it used and were told that it was "refurbished".

It would frequently momentarily cut-out during peak
audio demands.
We weren't sure if this was normal or not.

I had written Mackie about it but they weren't sure
why it was behaving like that.

Then, one day, just as we were all set-up and ready
to start an outdoor performance .. poof! It went
completely dead .. no pilot light .. no nothing.
Luckily, someone in the audience ran home and
brought us their PA and we played acoustically until
they arrived :-)

Anyway, I was able to coerce a schematic from Mackie.
I think I had to sign over my first born boy, but they
did give me a copy. (I think they are concerned from
a liability law-suit point of view.)

I must say, it is an engineering marvel. It has a
switching power supply and class-D audio power amp!
(Class D drives into saturation and cutoff and pulse
width modulates the audio output! This makes for an
incredibly small power amp .. no big transformers.)

Upon opening the unit, the AC power fuse was in tact
but the power supply was indeed dead. And, there
were signs of someone having reworked the power
supply and smearing heat sink compound around the
power FETS .. sloppy job.

Instead of guessing what the last repair person did,
I just picked up a replacement supply from Full
Compass.

The board has worked well ever since. I don't think
it ever worked correctly after the previous "repair".

I guess what I'm saying is if you purchase used
equipment, make sure you know what you're getting.

And now, I'll get off of my orange crate :-)

Keep squeezin'!

--Big Nick