Dell DC Jack "Problem"

[Road Runner]

Guys I think this machine is gonna be one of the EXPENSIVE lessons learned.....

I have a friend whose daughters Inspiron 1521 had developed some kind of charging problem......I was TOLD by the father that the original dell power supply had seemed to stop working......he said the daughters friend had a power supply.....of unknown origin that would charge the machine but after time it stopped.....the mother supposedly bought a genuine dell power supply and it didnt charge the battery either.......mom and dad are divorced.....

Dad (my friend) brought it by with a new looking dell power supply and a universal aftermarket power supply.....

I checked the dell supply with my volt meter and got 19.5 volts......the jack inside the 1521 looked worn.....obviously had been subjected to a lot of different plugs going in and out......

I ASSUMED the jack inside the 1521 was bad........tore the machine down and got the jack out......

It had 5 pins soldered to the motherboard......once out I got my ohm meter and determined that 2 of the pins were "the same" zero ohms.......

2 other pins were the same......

the final fifth pin had nothing in common with the others.....

I plug the dell supply into the jack and check voltage.....19.5 volts as I expected with nothing on the fifth pin......

I try the aftermarket supply and get 19.5 as expected and also +19.5 on the mystery fifth pin........

I look at the factory dell supply and the aftermarket one closer and see the aftermarket supply has a small needle like center pin that seems to supply the +19volts to the laptop internal jack and the genuine dell supply either didnt have the needle like pin....or it might have been broken off.........

I am beginning to think that maybe I got a mixed up story from my "client" and maybe there is nothing wrong with the laptop jack.........

anyone here ever replaced the dc jack on a inspiron 1521 or similar dell that might have some insight ????

I have already ordered a new jack........

thanks
Rhett Duke

Road Runner Repair...............

 

[l337]

im thinking u may be right and the middle pin was needed i dont know the jack itself. but im wondering with the aftermarket supply will the pc boot up with battery removed? or is it totally dead like not showing no charge or power indicator lights

 

[Road Runner]

Well Sir......

I wish I could take the aftermarket supply and try it now....but the machine is all the way down........

I made a series of mistakes in the troubleshooting process......I SHOULD have tried thee aftermarket suppy to begin with but with the nice new looking dell supply reading 19.5 I assumed the problem was in the pc.......

I now know there is a third pin in the equation..........



I now have another dell power supply WITH the third pin.......

I'll just wait for the new jack to come in........put it back together and see what happens.......

Education is not a cheap thing.......I seem to learn the most beating my head against the wall for no reason too many times though

 

[blackburgpchelp]

I've done a fair number of Dell DC Replacements, and have learned that a lot of dell power supplies use the thin middle pin to send a validation signal to the motherboard. If that middle pin is broken, or an aftermarket power supply is used, the laptop will power up, but the battery will not be "allowed" to charge. In fact, on boot up, the BIOS will warn that an unknown adapter is being used and the battery will not be able to charge. This can and may be turned off in the BIOS however, so the warning may not appear.

Hope that helps.

Rance
Blacksburg PC Help

 

[AtYourService]

some dell charger barrels arent like a normal charger, when u test with multimeter u need to touch the inside of the barrel for ground and the pin for positive

 

[JRDtechnet]

Atyourservice is correct, the outer sleeve is your ground and the inner sleeve is the positive. The center pin is what dell uses to communicate between the adapter and the laptop to make sure its a genuine dell part and whether its a 65w or 90w unit so the laptop can adjust the charge time accordingly. If the center pin is broken or faulty the laptop will still power up but it won't charge the battery. The center pin shouldn't have 19.5v running through it, you probably were touching the inner sleeve when you got that reading.

 

[usacvlr]

The info above is right about the plug pinout. The jack itself has 6 grounded terminals, 2 19.5 volt positive terminals and one 3.3 volt terminal. The three pins clumped close together at the back are 19.5-3.3-19.5

 

[Road Runner]

thanks for all the time yall took to help me........

In the final analysis the "NEW" dell Charger either came defective from the factory or the customer broke it......the "AFTERMARKET" universal charger sold by one of the "BIG BOX" stores used the WRONG adapter tip.........I got the right one from the supplied ones and its a-ok...

I replaced the internal dc jack as I already had the machine torn down........I definitely hope this will be one of the last times I work off assumptions without more research and tests......


yea right