On 26 Feb, 00:25, wrote:
I have a Dell inspiron E1405 and the headphone jack was broken off the
motherboard. I either need to get a replacement jack or figure out
what solder points to jump in order to get the speakers to work. Here
is a picture of the motherboard and the solder points.

http://i35.photobucket.com/albums/d1...eadphone002_re...

Does anyone know what solder points to connect in order to get the
speakers to work on the computer. Or does anyone know where to get a
replacement jack?

Thanks!

D

Help is here! I have just repaired an HP Pavilion N5412 laptop with an
identical socket that had been smashed. The audio to the socket is
separate to the speakers. Your pin 2 goes to the plug's ring, pin 5
goes to the tip, and ground pin 7 is common. Pin 3 makes contact with
pin 5 when the plug is absent. Pins 1 and 4 are normally closed, but
are open when the plug is inserted. Pin 4 goes to a logic gate pulled
up to 5V via 100K, and mutes the speakers when the plug is inserted.
There is a screening cover over the contacts, fixed by pins 6 and 8.

To make your speakers work, all you have to do is join pin 4 to
ground.

Here in Surrey, UK, the only high street shop that has electronics
components is Maplins. They have two types of 3mm stereo socket,
different layouts but having only 5 pins - tip, ring, & common, plus 2
pins that make contact with the tip and ring pins when the plug is
absent. They are obviously intended for circuits that feed headphones
by breaking the speaker feeds, and don't fit your board.

In my case the socket was mounted on a separate board, so I used a
piece of breadboard to mount the Maplin socket. As the tip and ring
are fed via isolating capacitors to avoid putting DC on the 30 ohm
headphones, I put 330 ohm resistors on the tip and ring pins to
ground, to keep these pins at ground in the absence of a plug. I then
connected a 6K8 resistor between one of the pins that make contact
when the plug is absent, and the line to the logic gate. When the plug
is absent the gate is pulled down via 6K8 and 330R, and when the plug
is inserted the pull-down is disconnected, muting the speakers.

This worked, but gave trouble because audio peaks get to the muting
logic and break up the speaker sound. To get round this I added a
0.1uF capacitor between the logic line and ground, to reduce the audio
getting to the logic via the 6K8. However when powering up the
computer, or inserting/removing the headphones, a very short squeak is
produced. This is because the logic voltage rises slowly owing to the
capacitor, and there is instability at the switching threshold. The
capacitor value was a compromise between length of squeak and stopping
speaker distortion.

My solution is obviously not as good as finding a proper socket.

Dave W