Boss bv9557 will not power on

that is wrong the red is positive .black is negative ,that is earthed to the body of the horn .which in turn is earthed to the car body.by the bolt holding it on.

To be sure you need a schematic. You can actually take a look at it to see if is labeled or check polarity with a meter.

There are possibly 3 wires that can do this if not connected properly. One (probably red) should go to the battery. (memory, settings, and clock) . The second one should come from the fusebox( usually yellow). This should be connected to acc to come on with the keyswitch and power it up. IF this is in the wrong connection, your problem would exist. The third one(only on some units) usually an odd color or striped, should come from a pin on the head light switch to dim the radio lights, when you turn on the car lights, so it won't be so bright in the dark as it is in the day. I would double check all of these, especially number 2 on the fusebox. Try different positions on the fusebox until you find one that works correctly.

black and red will goto 1 speaker. and blue/yellow to the other. typically red and yellow are + and black and blue are -. the crossover board might tell you which is which where they solder to it. but i'm pretty sure the black/red goto woofer. try hooking up both to woofer and listen to it. 1 way is going to sound horribly wrong lol. that will mean you hooked up the tweeter leads to the woofer. but DO NOT HOOK UP WOOFER LEADS TO TWEETER. thats why i say to do it on woofer.

Check your power adapter or battery if you are using a battery.

Hi,

The black wire is ground and the red is live, also the yellow is live and the blue is ground. Probably the black and red wires go to the woofer.



Regards.

You can probably trace which colors go to the smaller of the amps... Yellow is often used for tweeter but there really is no standard. Striped wire is probably the minus lead. If a pair is heavier, that would be the pair for the woofer... and red is often positive for woofer and black the minus. Searching the Mackie schematics doesn't really show colors. You could call their service dept.

First thing is to check that powr adapter is the correct one and/or battery is good. Light will come on with near dead battery or wrong power adapter... Wrong adapter can damage the unit.

The problem is with a bad power connector.

The connector has a spring tab that touches the center pin when the external power is NOT plugged in. This tab brings the battery power to the center pin. Some of the springs as an alternative act as a switch to a contact for the negative lead of the battery. These suffer the same problem of loss of spring tension and failure to contact.

The spring gets weak and no longer touches and battery power will not work.

First, make sure the jack is not shorting against the circuit board or an adjacent wire. Check the wire connections at the jacks and switch. Sometimes these wires disconnect due to poor solder joints on the switch or jacks. Make sure the circuit board is not touching the enclosure or pot assembly.