Mackie PPM 1012 mixer/amp

[Geeeetarzan]

Hi Folks, I've got a Mackie PPM 1012 mixer/amp that i got dead, no lights. Fuse is internal and is not blown. The power supply powers up without popping the fuse, no smoke no smells.No components seem obviously smoked or swollen. I'm a tube amp guy so i'm fine with high voltages knowing this one isnt that high, and have a decent fluke meter. With no schematic i'm not necessarily in my element. With a schematic and voltages i could chase. Anyone have the schematic? Or is anyone familiar with specific quirks on this one? I was told it was running at the end of a long extension cord outside and died of its own accord. No drops/spills. I'll upload some pics. - Thanks

[Per Hansson]

Re: Mackie PPM 1012 mixer/amp

Start by checking the diodes as from the other thread you replied in these seem to be a common failure point.

[Geeeetarzan]

Re: Mackie PPM 1012 mixer/amp

thanks. There's a large bridge rectifier and post that i'm getting +/- 165v.
I was told they purchased it new and it died after a few gigs. It actually looks like the bridge rectifier and a couple regulators have what sure looks like "non factory" soldering.

at the ribbon connector i also get a couple 15v reading but the board is odd(to me)
Seems to have separate ground planes. Grounds aren't common and aren't lifted or separated by a resistor. Earth is grounded at the input on chassis and connected directly to the PS board. As mentioned in the other thread, the PCB with this is seemingly the same as the 608, but the components and final circuit seem to differ so having the right schematic to chase voltage would be fantastic.