(Almost) dead Mackie CR1604

[vintagedreams]

I have a Mackie CR1604 (non VLZ) that I got a hold of for next to nothing, but it has some issues. The power light does not come on, but when power is applied, the overload light on the lowest 6 channels comes on, in a somewhat random sequence, not all at once. I have it completely apart on the bench right now. So far I have:

1 - Tested the DC outputs of the power supply, seems fine (+ and - 17 volts, and +42 when the phantom power is on)

2 - looked for any cracks in the PC board

3 - reseated the ribbon connectors

I am not 100% sure the ribbon cables are in the right positions because I think someone was fiddling inside this mixer before based on the missing screws and one larger screw forced in the hole Oddly, Mackie used two ribbon cables with the same number of pins to connect the two PC boards, and there's no way to tell which one goes where from what I can see.

I will probably try reheating all the joints in the power supply board, because I know that's been a problem with these. They get real hot.

If anyone could help me with a service manual, schematics, or helpful advice, I would really appreciate it.

Thanks!

 

[guavatone]

I don't know these unit's but 17 volts seems odd for an IC based board. Look for more regs in the mixer that drops DC again.

 

[stinky]

If you've already got it apart try replacing the 7815/7915 regulators. I just had one of these on my bench last night and a regulator went bad and took out it's rectifying diodes as well.