Hum from dell laptop power adaptor when using a sound system

Laptop adaptors are usually 19volts not 9.

You may have the wrong AC adaptor, Dell is very picky when it comes to Power adaptors, it must be original OEM Dell for the laptop to recognize it, any after market no name brand even though it has the right specs and is made for your model will power your laptop but the circuit to charge your battery will automatically be closed

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There could be a problem with the battery. A fast check to determine whether you have a problem with the power adapter, power cord or the laptop's battery is to turn off the laptop, remove the battery, connect the power adapter, turn on the laptop & see if it works.
If the laptop works directly from the power adapter with the battery removed, then the power adapter is good. In this case we can suspect that the battery is defective & needs to be replaced.

If this did not work, try also disassembling the laptop & make sure that all main components are seated properly. Also make sure that all ribbon cables interconnecting the various components of the laptop are tightly connected.

Hello,

By chance have you tried making sure the laptop is not too close to the speakers? Sometime you will get feedback when the source is to close to high powered speakers. Also, check your jack cord and make sure no splits/cuts are visiable and the plugs are fully inserted.

Good Luck and keep making great music. Aloha.

C2Solutions

Try taking out battery and plug in power. If it works, battery is faulty. If not,
Try taking out your hard disk plug in power, if it works, hard disk is faulty. If not,
Try taking out memory card, if there's a sound, memory card faulty. If no sound, it's your motherboard that is causing the error.

Note: If machine is under warranty no need to pay for the repairs.

FIRST REPLACE YOUR BATTERY, THEN ALSO CHECK VIRUS WITH AN UPDATED VIRUS CLEANER.

The blinking orange battery light generally indicates that the battery isn't working properly, usually going out and not charging properly. In this case, since the adapter will not power the machine without the battery, and it should, I'm going to say that the adapter is going out and not getting the proper amount of power to the system. Try replacing the adapter. Be sure to replace it with a Dell replacement, the Targus brand universal adapters do not work well with Dell machines, and in most cases won't work at all.

Make sure you are using a 4.62A Power Supply (90watt) some of the knock-offs are only 65w (3.34 A). And you will never have enough current to charge the battery.

It will only run the laptop, but not charge.

The mobo sounds like it is good, if you had a power issue, you would have orange lights or blinking, and it would not come on at all with any power supply.

Hi,
As a system gets a little age on it, the battery naturally decays. Also, each time you plug the ac adapter into the laptop, the adapter connection on the motherboard becomes a bit looser on the solder points, all of which contributes to the symptoms you describe.
You could try a fresh battery.
The standard rule is a battery is wireds to last between 500-600 cycles, then it's dead. They claim it's a safety feature.
Good luck, hope that helps.
Thanks