At the time only one speaker is working untill twisting the pin

Pull out the grill buy using a paperclip with a short 90* bend on
on one end. Place it through one of the grill holes in the corners and gently tug. Work your way around the edge of the grill until it comes out. Be careful not to bend it. Unscrew the 6 phillips screws on the speaker panel. Then use a thick bladed putty knife on the groove that surrounds the whole box. Twist the putty knife handle a little at time, work your way around the whole box. It will eventually come off. Just be slow and careful to avoid nicking up the box.

I would suggest this generic Power On switch,

1) http://www.directron.com/atxswitch.html,

and the Red, and Black twisted pair of wires go to the Power On switch.

Your statement of ,"....don't know which of the colored pairs of wires go.....", leads me to believe you may have all of the Front Panel wires disconnected.

How about information as to where ALL the Front Panel wires go?
(Provided I have correctly interpreted your statement)

Back in the time that the eMachines T2542 was made, TriGem was the motherboard manufacturer.

The Model Name of the motherboard is Imperial, and the Model Number of the motherboard, could have been one of four variations offered.

Model Name: Imperial
Model numbers could be G, GL, GV, or GLVE
(Imperial G, Imperial GL, Imperial GV, or Imperial GLVE)

ALL four variations used the same Front Panel header.
(The connector on the motherboard the Front Panel wires connect to, is named the Front Panel header)

I would like you to view this page,

http://www.e4allupgraders.info/dir1/ecase/support/front_panel_header_support.shtml

Scroll down to the heading -
Trigem Imperial Front Panel Header Pinout.

A) Pins 1, 2, and 3 are for the Power On LED light.

B) Pins 5 and 6 are for the HarDDrive activity LED light.
(Pin 4 is not used. NC. No Connection)

C) Pins 7 and 8 are for the Power On switch

D) I wouldn't connect any wires to Pins 9 and 10, nor Pins 11 and 12

E) Pins 14 and 15 are for the Reset switch. (The button you press to restart your computer.
If the T2542 doesn't have a Reset switch, don't worry about it. There are many other ways to restart your computer)

F) Pins 17 18, and 20 are for an internal speaker.
This speaker is used for BIOS Beep Codes.

In the chart to the right, you will see GRD used many times.
GRD stands for Ground.
ANY Black wire in the twisted pair of wires, is a Ground wire.

Most of the eMachines I have worked on, use a Red, and Black pair of twisted wires for the Power On switch.
I could be mistaken on the T2542.

Best method, is to follow the color code of the wires that come from Pins 7 and 8, and be sure.

Suggest you abandon the mini-phone jack connection - sounds like a wire is broken in that connector. Use the RCA stereo outputs from your TV into the Dell surround system. You may need a couple of adapter cables to make that work. Take photos of the connectors on the back of your TV and on the back of the Dell Surround system. Take those to an electronics store like Best Buy and ask for help there to get the cables you need (telling them that the mini-phone (headphone) plug is giving you trouble.

I had this same problem with my Onkyo sr701, and it turned out to be a twisted kink in the speaker wire. Run a sound check to each speaker separately (from your receiver menu) and turn each one up until the receiver shuts off. Check the wire to the speaker that caused it to shut off and make sure the +- ends are not touching each other at either end, and that there are no twists or kinks along the way.

you can use this simple steps to know the pin details sir.....
1.short any two pins with tester, of the front panel connector pins of motherboard.continue this process until the system will be ON.when the system will be on then ,you found out the power on button.
2.after find out the power ON button ,then again short any two pins with tester until the system will be restart .if restarted then you are founded the RESET button.
3.now jack the speaker button in any pins, restart the system .until you can hear the beep sound. (restart must every time you connect the speaker pins changed)

4.same as you can found the led pins also.

Note: Dont worry about any problem will be affect the motherboard.Becase this is normal Technic sir... 100% you can follow it.Thank u sir... Have a nice day...

Your receiver is going into protection. The first thing to do is disconnect all speakers at the receiver. Unplug the power cord, then let it set for 30 seconds. Plug it back in and power it on. If it stays on, you have either a wire shorting out at the back of the receiver, something that has pierced the speaker wire en-route to the speaker, a wire touching the other at the speaker or a blown speaker.

Speaker wires should only be trimmed about 1/2" bare at the terminal and make sure you twist the braid so it does not fray. Then connect speakers one at a time, testing the receiver power each time until it either shorts and cuts out, or, you have solved the problem. Hope this helps. If you need more help, post a comment and I can help you some more

Maybe, it worked for me. my rear speakers workt ramdomly, often not. so i re solder the relay for the rear speakers, now it works fine everytime, a hole movie and some random on and offs, it can't do any harme to try=)

hi , i just saw ur mail although I do not have the solution to this but I am keen to know how you are using these speakers as I too have identical beolab 6000 and beolab 9000. I was thinking of connecting them to a preamp. What do u suggest ? Pls guide

The first thing I would check has already been done, the only other thing would be fuses. I am preety sure there is a protection fuse at ever channels output to protect against a dead short. I am sure you have already fixed this problem but I thought I would give it a try. Let me know what you found.

Check the speaker cable connections between the Plasma Display and the speakers. replace it if needed. it will work.