Dell Precision M6600 Not Charging Battery and Reduced CPU Speed

[shovenose]

Hi all, got this one quite cheap off eBay. It came with a 240W Dell genuine charger.

Initial issue was the battery wasn't charging.

I thought the battery was the problem, so I bought a generic replacement off Amazon.

No such luck. The battery came 80% charged, well, it discharges fine, the laptop stays on when unplugged from AC power, so now it's at 77% but if I plug it back in, it doesn't charge. Just stays at 77%.

I thought it was a charger issue. I tried two other chargers, a 130W Dell genuine charger and a 65W knockoff charger.

With the smaller chargers I get the error very time the computer is powered on or rebooted that the charger isn't powerful enough, performance will be limited, and charging will be slow.

Then I noticed that the CPU speed was throttled. With the 240W power supply it gets stuck at 0.1GHz. Oddly enough with the 130W power supply it gets stuck at 0.6GHz. If I open the ThrottleStop app from TPU then close it the CPU performance goes back to normal until I reboot the PC.

If I disable SpeedStep and C State Control in the BIOS the CPU performance is OK.

I've Googled and Binged for hours and there are so many solutions for both the battery not charging and the CPU throttling on Dell laptops of various generations/models with various resolutions. In terms of the charging issue most people only had it within Windows and it turned out to be a software issue. But since mine will never charge whether in BIOS, Windows 7, 8, or 10, or various Linux distros... Yes I've tried everything, I figure it's a hardware issue.

But if I have ruled out the charger, battery, and software, that only leaves either the DC jack or the motherboard.

I did manage to update BIOS from A16 to A18 with no difference.

Any ideas on further toubleshooting or a resolution? I don't mind the extra chargers and batteries as I also own a Precision M6700 and they are interchangable. But I'd love to get this working so I can sell one of my other laptops.

Thanks for any help.

[mon2]

Re: Dell Precision M6600 Not Charging Battery and Reduced CPU Speed

Hi.

1) Review the schematic - page # 63/82 - charger circuit.

2) Meter in DC volts mode (20 volt scale is ok or higher) - what are the voltage readings for the following ?

< attach the power adapter & attach the battery >

BQ24747_ACOK

CHARGER_SMBCLK
CHARGER_SMBDAT

BQ24747_LXP

BQ24747_CSIP
BQ24747_CSIN

VCHGR

3) Mosfets may be the fault here but can inspect those with resistance checks after the above.

[shovenose]

Re: Dell Precision M6600 Not Charging Battery and Reduced CPU Speed

Hi.

1) Review the schematic - page # 63/82 - charger circuit.

2) Meter in DC volts mode (20 volt scale is ok or higher) - what are the voltage readings for the following ?

< attach the power adapter & attach the battery >

BQ24747_ACOK

CHARGER_SMBCLK
CHARGER_SMBDAT

BQ24747_LXP

BQ24747_CSIP
BQ24747_CSIN

VCHGR

3) Mosfets may be the fault here but can inspect those with resistance checks after the above.

Thank you, give me a week or so to check this and I will update.

[Stevedb]

Re: Dell Precision M6600 Not Charging Battery and Reduced CPU Speed

Look also in bios if charger and battery is detected

[shovenose]

Re: Dell Precision M6600 Not Charging Battery and Reduced CPU Speed

Look also in bios if charger and battery is detected

Yup battery health shows as normal for both the old battery stuck at 0% and the new one around 77% percent.

And charger wattage is shown correctly. 240w, 130w, 65w…

[Stevedb]

Re: Dell Precision M6600 Not Charging Battery and Reduced CPU Speed

Ok check also the first mosfet for short between S-D , D-G. And G-S. And do the measurement what mon2 said.