Dell laptop show ""AC adapter not recognized"

Many of our customer who buying the dell laptop ac adapters from us because their laptop showing them a message of  "AC adapter not recognized", the symptom are as follow:

(There are other versions of this message, depending on your laptop model. You can disable the warning in the BIOS on some dell model, but it won't fix the problem)

This failure can come out of blue. The laptop battery indeed stop charging, and your computer does run slower after the message showed up. Try to plug the adapter into another same model dell laptop, you get the same message. So you just got a defective charger, right? Wrong! Or at  least it's not that simple. Let's dig into this problem a little bit.

If you continue to use the same adapter, the problem may come and go, but the "not recognize" message will come up more and more often until one day your laptop ac adapter stop charging at all. If you notice, the adapter is just not charging the laptop.  Have the ac adapter plug in and take off the battery, you will see that you can still use the laptop without any problem, which means that the ac adapter is actually supplying power and the power supplied is enough (90W). So what's the REAL problem?

If you goggle this famous warning message, you will see this problem is very common and it mostly happen around one year of the usage, which is about the warranty expiration date. What a coincident. The solution? Replacement of the ac adapter which will cost you around $80 at dell's web site. Does this price tag remind you of something? How about the printers manufactures? You bought the printer for $40 bucks, and the ink cartridge actually cost more than the printer.

Yes, that's right. Dell is using the same tactic. The true cause of this problem is that dell have two chip installed on both of the laptop and the ac adapters. Those two chip communicate with each other to make sure the ac adapter is a Dell made charger, If the chip is missing or damaged despite the charger may be perfectly functional, the laptop will disable the charger and run slower intentionally. To make the whole thing worse, the design of the check-if-it's-a-dell-charger "feature" is very faulty thus people are wasting perfect good ac adapters. Here is the detail information of how those two chips works

Based on the findings with the DELL 90 Watt AC Adapter, web site search engine phrases & statistics and incoming e-mails, the following sticks out:
1. Failure pattern for DELL laptop power problems is wide spread - worldwide
2. When inside warranty, DELL ships new AC Power Adapters, replaces motherboards for free
3. Two DELL Laptop power failures are top ranked: ID chip inside the DELL AC power adapter has died Power jack is loose on the motherboard. (which is repairable)
4. In extreme cases DELL replacement AC power adapters also start failing with the same laptop
5. Motherboard replacements are sometimes unnecessary due to misdiagnoses.
6. Failure pattern indicates a design / manufacturing failure

This problem is seen with the DELL 90 Watt AC power adapter with Model number:

PA-1900-02D2 and revision number REV A04.

The DELL 90 Watt AC Adapter is supplied with the following laptops:

DELL Inspiron 1150, 9200, 9300, 9400, 1501, 300m, 500m, 510m, 600m, 600mcr, 630m, 640m, 6000, 6400, 700m, 710m, 8500, 8600, 8600CR
DELL Latitude 100L,D800, D810, D820, D400, 410, D420, D500, D505, D510, D520,D600,D610, D620, X300 DELL Precision M60, M20

The laptop power adapter is known by the following part numbers: PA-10, NADP-90KB, PA-1900-02D, PA-1900-02D2, U7809, C2894, 9T215

there are workarounds on this issue may or may not work. Worst case scenario, you can find a cheap (of course, price, not quality) replacement Dell ac adapter for the above models here.