Solved! Dell Studio Laptop Power Switch Wiring Identification

[jackgs0254]

I have an old Dell Studio 1440 laptop in which the power on switch has become totally
loose and nonfunctional. I was able to use it for a while but when wires started coming loose from the tiny little circuit board assembly that was the end. There were either
three or 4 wires soldered to the board (I think 4) red, black, white, and tan (light brown). I think 2 wires were for the actual switch and 2 wires were for the onboard LED
indicator light. If I could jumper the right wires together, I think I could make it work,
but ideally, instead of straight jumpering I would like to put in a push button switch
to replace the bad switch and an LED or small nonpolarized filament light bulb to replace the original LED indicator light. Does anyone know what voltage rating I need for the indicator light and if I use an LED do I need a series resistor and how many ohms ? I would really appreciate this information also of course need to know which 2 wires to connect to switch and which 2 wires go
to the LED and polarity for LED wires. Thank you very much. Sincerely, Jack G..

 

[jackgs0254]

I was able to solve my own problem. I ordered and received a replacement assembly board for the power switch on my Dell Studio 1440 laptop,and fortunately it was identical to the board I needed to replace. After comparing the 2 boards and making resistance measurements with a multimeter, I found that
1)Red,black,white,tan was the order of wires soldered to the board starting with red wire CLOSEST to the edge of the board.
2)Red (+) and black (-) are wires to connect to an LED and a 3-volt LED will work with a 1500 ohm resistor.
3)White and tan wires are for connecting to the power switch.
4)I just ended up using the new Dell assembly board that had 2 copper pads for the switch contacts, but no way to simply push
the 2 contacts together, so you either have to solder the pads to a push button switch, or find some other way to make contact
between the 2 pads which are on OPPOSITE sides of the assembly board possibly a pair of big metal tweezers. Once you make
contact and the LED turns on you no longer need to keep the 2 pads contacted.
So, that is it, solved my own problem, case closed. Note that the little assembly board is VERY DELICATE. Handle gently.