Dell XPS M1730 shuts down randomly, code #M1004, false overheat error

Hello,

I try to revive a weird dell XPS M1730 thrown by someone because of the random shutdowns the machine is having.

Because I feel challenged by this problem, I did a lot of troubleshooting since I found it, backing the video card and the mother board, to no avail, in the oven, like some other posters had success.

The story with the pictures you can see-it here : http://www.dslreports.com/forum/r28409593-Dell-XPS-M1730-shuts-down-randomly-code-M1004-the-story

I do not want to reload that much stuff here, so please see there the pictures.
Normally, in the faulty state, the HWMonitor shows 0 RPM for CPU and GPU, even when the machine was warm.

Recently I found that by unplugging the touch pad connector (and keyboard) from the motherboard, it restores the normal fan speed readings to around 2000 RPM in HWMonitor!
The drawback is that without the connector plugged in, the power switches automatically to battery power, another weird stuff.

Now I removed the touch pad and took all apart, the small cables, reconnect all back, it seems to be working.
I will continue the monitoring test, in HWMonitor, when I do Fn+Z it brings down the fan RPM to 0 for 4-5 seconds, then it goes back again to normal 2000 RPM by itself, this has never happen before when it was faulty!

I think this is the normal behavior, and should be checked by those having this machine still alive, do an Fn+Z while having open the HWMonitor and look for that behavior.

No wonder some have changed the videocard and the motherboard and still no cure because it was the tricky touch pad! Ha ha, clever DELL engineering.

Other symptoms, like the overheating because of low fan speed, could also be explained by the bad fan controls, if that is running thru the touchpad chips.

When I did the BIOS update from A6 back to A11 , in DOS mode( because the update file run under windows it was giving a file not found error) I saw the update was in 2 steps, the BIOS and the “keyboard controller”, probably is that chip under the touch pad.

Initially I was very frustrated before I found this behavior that relates the shutdowns to some action, because before, even when the machine was cold, plugged in, it was turning off instantly and after that the BIOS message was coming up, the same stupid #M1004.

Does someone has the schematics so I can check the signals involved in that touch pad /keyboard connector to the motherboard?

It would be much appreciated.

Thanks

 

Hello,

The shutdown is still hapening, meanwhile I found the schematics, for free, on elektrotanya, I love their motto : This site helps you to save the Earth from electronic waste!

Now is a question of time to search the signals like the THERM_STP# signal which turns off the power instantly, exactly like my simptom.
I have to find the datasheet on that EMC4001 chip which controls the fans speeds and all the thermal business in the laptop.
I think this chip is loaded by BIOS with the fan tables, to control the speeds ( see the FAN DAC2 signal to the GPU Fan)
If I came up with the solution to my problem, I will posted here.

Regards

 

Hello again.

I think I got –it this time, it’s so useful to have the schematics!
The chip causing the shutdowns is the SMSC EMC4001, the power, fan and thermal controller.

This is a chip you will not find any datasheet for, even on the SMSC website.

On the web is listed as an 4 port USB chip!, nothing to do with the one on the XPS mother board.

It’s like they never produce-it! Well done Dell for using such crappy components.

It’s location is between the CPU and the chipset (see the pictures in the first post link).
I had to remove all again to get there. In the pictures attached, lifting pin 3 on those transistors is the easiest solution to stop the instant shutdown coming from those signals.

There must be a design fail, now I understand better, when I was plugging the power cord, it made some of those signals to trip and therefore the instant shutdown, also the noise could trigger the signals.

Because I have no tools to access by software those signals and see which one is at fault, I just removed them all.

That’s it folks.