Posted on 26/09/2021
The AC power adapter wattage and type cannot be determined
The battery may not charge
The system will adjust the performance to match the power available
Please connect a Dell 65W/90W/120W AC adapter or greater for best system performance
To resolve this issue, try to reseat the power adapter.
Strike the F3 key (before the F1 or F2 key) if you do not want to see
Power warning messages again.
Strike the F1 key to continue. F2 to run the setup utility
Press F5 to run on board diagnostics.
In CMOS setup the BIOS shows AC adapter Unknown or IDLE. It will not charge the battery.
If you connect charger after boot laptop by battery the OS windows show error 'PLUG IN NOT CHARGING'.
In first look every engineer will be quite certain on that the power cable of AC adopter had broken internally due to the constant flexing and this is case to plug . This happens on almost every laptop power adopter.
In my last few years service I found 95% fault in dell A/C power adapters in this is that adapter not recognizing case.
This kind of faulty adapters mostly ID pin of charging cable has found temped or broken Due to this laptop unable to recognize the charger wattage.
This center of dell adopter knows as ID pin of adopter.
Every time this is a very easy to fix this fault for a person who just know decent enough about soldering and basic electronics stuff like continuity testing and voltage measurement.
but if adopter is working fine with any other laptop then how we can fix the problem.
So dear friends, In this post I will tell how to repair any dell Laptop charger not recognizes by BIOS. And not recognizing the working OK A/C adapter.
If you having same problem with any DELL laptop first of all check the basic things.
Get a faulty motherboard out from laptop first with the eyes sweep it and see no didn't burn out marks, there is no damage to the skin and see whether the various plugs, socket-outlets skew, resistance, capacitance PIN is met and the surface is burned, the chip surface cracking, motherboard copper foil is blowing. Would also like to see if there are any foreign objects into the motherboard components. Encounter questionable places.
Check DC jack, connector or cable for proper connecting between DC jacks to main board if present.
Then start the next step by testing the voltage or components one by one
The best thing in DELL is they most likely be using same circuit in their all models so this thing make it easy to repair for all models.
I have a circuit which has answer of our problem. But fist of all need to know something very important things about Dell's adapter.
Time to get know how the adapter data signal goes to I/O, basically there is a ID input comes from DC connector to the N-type Mosfet drain and the souse of type Mosfet connected with the I/O chip using a resistance in series. Gate of the Mosfet controller by a protection circuit commonly there is a NPN transistor you can see circuit diagram.
I draw a small circuit to understand how DELL charging adapter's ID data get in to main board of laptop.
Note:- Components number and value can be change!