How do I repair the power connector? I think there is a short in the connector.

There are many causes of buzz, so it should be checked step by step :
- Bad connection on the input connector, or cord.
- Amplifier, basically have the block diagram like this. View image.
If in one block damage, buzz can be heard.In the amplifier.
Generally occurs in the PSU and / or power amplifiers.
Fix it to the experts,because it requires a good knowledge of electronics.
Blown speaker cone, does not cause a buzz.
Short circuit along the wires supplying the audio, it will not cause any sound in the speakers, including the sound of music.
Try also, disconnect the input connector, whether the buzz is still audible. If after the input connector is removed, the buzz disappears, the possibility of buzz came from another device before the amplifier.

Chances are you've blown the output transistors. Speakon connectors cannot short out but jack connectors can and if it was not inserted properly you'll have presented a dead short to your powered mixer. In any event it is really bad idea to connect anything when it's switched on. If you're really lucky replacing the output stage (which will probably be dead short on the transistors) and re-adjusting the bias should sort you out.

Either way will work, however your friend's method probably would be slightly better since it goes through less stages within the PMP2000. The "left and right power amp inputs" are the INPUTS to the power amp in the PMP2000 and hence are the best places to connect the mixer if using the PMP2000 as only a power amp. Note doing this will LIKELY disconnect any other input to the PMP2000 from the power amps in it... that is all the preamps in the PMP2000. DO USE TRS cables!!! and power both units from the same receptacle to avoid ground bounce.

Don't even think of using a universal adapter !!! I could not find the schematic of this unit, but other Gemini mixers like this use center tapped AC power transformers. Any universal adapter will be DC, not AC. I have found that the FX7000 indeed uses an 18 VAC adapter... Try this as a source:

http://www.topdjgear.com/gemini-110vac18v.html

This happens when you have lose earth connection from your main source power supply. Check the earth connections (grounding) which should be available in the mixer, i.e some power cords don;t have earth wire, so change this if you think yours don't have it. Also check the grounding of the other items attached to your mixer, basically grounding is very important to reduce the static shorts. Try changing the power supply source, change to other outlet and check if it is OK.

Usually the connector that is board mounted is the problem. I would OPEN the unit as there may just be broken solder at the connector inside. If the connector requires replacement, find one at Digikey.com by searching for "power connector coaxial".

Hint: In the future install one of those little lamp switches that are in a little plastic box with knurled knob sticking out the sides. ONLY break ONE wire from the adapter to avoid getting the connections reversed. Since the wires are smaller than lamp cord, tack solder the wires to the piercing points of the switch .

Iis ALL your equipment powered from the same receptacle? It had better be... ground bounce can destroy input circuits in these units. I don't have the schematic but a common problem where XLR connectors go into a mixer is they have radio-frequency noise suppression caps to ground from each side of the XLR input. These caps are often lower voltage rating and can be popped by ground bounce or ungrounded equipment being connected before the ground connection is made. When one goes, there is loss of half the voltage or 6 Db of power gain. Since these RCA's are right at the XLR they MAY connect and have these caps and one may have shorted. That means the repair shop I am afraid unless you are adept at electronics. Most of these mixers are a pain to work on that area as all the knobs and screws have to come out/off to get the circuit board away from the panel to work on... I wish I had the service manual to give you more info...

PLEASE in the future power all equipment from the same receptacle or power source AND for units that don't have three wire power cord, NEVER change cables that can break the ground connection such as the RCA cables while power is on to any of the equipment. This will save repair bills...

This is from your friendly electrical engineer that works with this stuff and repairs his own...

You didn't mention what brand powered mixer you have, HOWEVER MOST powered mixers also have a line level monitor and main output jacks. These are almost always 1/4 inch jacks. In any case you should be using BALANCED lines to the powered speakers using either XLR or TRS connectors on the ends. Please tell us what powered mixer you have so we can give you better answer regarding which connections to use. IF for some reason your mixer does NOT have line level outputs, you can use a high level Direct Box to condition the powered outputs to be sent to the powered speakers..
Also make sure ALL your interconnected equipment is powered by the same receptacle or source to avoid damaging due to ground bounce on utility lines and circuits. This often means running an extension cord from the stage where the powered speakers are along with a snake of the audio cables.

Often the cord has broken wires. First try to repair the power supply.

Also check the connector in the mixer as they can get damaged by side pulls of the cord.