Question Oldie but Goldie... With Strange

[trebor58]

Hello, I have a Dell M6400 that was working fine, then stopped (just died). I switched it back on, and it did not boot; instead, the No. 9 bag (Num Lock) led flashed 23 times and then remained on. According to the Dell Precision™ M6400 Service Manuals, it signifies a processor error.

So here is what I have tried so far.
1) Removed and cleaned the CPU, reseated it, applied new thermal paste and retried and got the same error.
2) Purchased a replacement CPU, applied new thermal paste, and retried and got the same error.

Now, thinking this is not the processor, I purchased a replacement motherboard and tried both CPUs, but I still get the same error message.

So please, any suggestions...

 

[LordVile]

Hello, I have a Dell M6400 that was working fine, then stopped (just died). I switched it back on, and it did not boot; instead, the No. 9 bag (Num Lock) led flashed 23 times and then remained on. According to the Dell Precision™ M6400 Service Manuals, it signifies a processor error.

So here is what I have tried so far.
1) Removed and cleaned the CPU, reseated it, applied new thermal paste and retried and got the same error.
2) Purchased a replacement CPU, applied new thermal paste, and retried and got the same error.

Now, thinking this is not the processor, I purchased a replacement motherboard and tried both CPUs, but I still get the same error message.

So please, any suggestions...

Can I ask why you are trying to keep this going?

 

[trebor58]

Thank you, LordVille. for replying to my thread. I know they are old machines, but I refurbish them and then pass them on to others.

I should/could scrap this and sell it as parts, but it is intriguing me what is causing this strange error, which I why I posted the question here. Ho[ing that someone may have come across this issue in the past

 

[LordVile]

Thank you, LordVille. for replying to my thread. I know they are old machines, but I refurbish them and then pass them on to others.

I should/could scrap this and sell it as parts, but it is intriguing me what is causing this strange error, which I why I posted the question here. Ho[ing that someone may have come across this issue in the past

These really shouldn’t be used regardless unless you really need some niche legacy software and never connect them to the internet. They won’t run W11 and aren’t secure. I don’t think they’d run W10 well considering they’re vista era machines. At this point you’re better off recycling them

 

[trebor58]

Thanks again for your reply; however, I have sold at least four of these, all of which are running Windows 11 23H2 & 24H2. I have one here ready to go, which is also running Windows 11 24H2 and have never had any problems... Okay, they don't officially run Windows 11, but with that said, they do run complete with all drivers and software up to date.

I have also sold the bigger M6500 and the M6700, all with Windows 11 24H2

 

[tgchan]

Thanks again for your reply; however, I have sold at least four of these, all of which are running Windows 11 23H2 & 24H2. I have one here ready to go, which is also running Windows 11 24H2 and have never had any problems... Okay, they don't officially run Windows 11, but with that said, they do run complete with all drivers and software up to date.

I have also sold the bigger M6500 and the M6700, all with Windows 11 24H2

Holy smokes. You have really installed win11 on those machines and no problem whatsoever?

 

[trebor58]

Yes, and they run great, especially when you add 16GB of RAM. When I sold the M6700, I added 32GB... Win 11 Pro MS Office 2021. Just need to work out why this one has a quirk

 

[COLGeek]

Is the BIOS on the affected system the most recent version available for it?

 

[trebor58]

Thanks, GolGeek, yes, it is A13

 

[COLGeek]

Thanks, GolGeek, yes, it is A13

Same memory with all the CPU and motherboard swaps?

 

[trebor58]

I did think of that and swapped the memory sticks over from a working M6400. Same result

 

[COLGeek]

What common component was used with all the swapping?

 

[trebor58]

The only thing I can think of is the graphics card, but that gives a different error code if that is at fault, along with any memory issues

 

[COLGeek]

Remove it and just use the integrated video to see if the behavior changes.

 

[trebor58]

There is no other video option as it's a graphics card

 

[COLGeek]

The CPU has integrated video, removing the GPU from the MXM slot forces the system to use the iGPU.

 

[trebor58]

The CPU does not have integrated graphics... See below


The Dell Precision M6400 is a mobile workstation that requires a dedicated graphics card to display video and function properly. The CPUs compatible with this model do not have integrated graphics processing units (iGPUs).
The M6400 was designed in an era where workstation laptops relied entirely on the more powerful, discrete (dedicated) GPUs, such as the NVIDIA Quadro FX 3700M, for all display functions.

 

[COLGeek]

Ok, what is the source for that quote?

I only ask because I have had other Precisions (owned 4 over the years) where they had both integrated and discrete.

What model are the two CPUs you have used?

 

[trebor58]

Great question, but now I am confused.
Here are the CPUs I have been trying...
Intel Core 2 Duo P8700 2.53GHz PGA578 Laptop CPU Processor
Intel Core 2 Duo P8400 - 2.26GHz Dual Core CPU Processor

The sockets on the two motherboards are 479M; the socket on the working system, according to CPU-Z, is 478 Socket P. Google states that the M6400 was only shipped with a 479M, but I have always installed a 478 socket.
So, I am going to try and locate a socket 479M CPU, all I can find isa 479 CPU, not a 479M

 

[COLGeek]

Those are rather old, and honestly, not worth spending money on for modern day use (beyond a lite Linux distro or vintage Windows OS). You are talking about CPUs from ~2008...17 years ago.

This Dell document doesn't give a lot of info, but it does list compatible families of CPUs.

https://dl.dell.com/manuals/all-pro..._mobile/precision-m6400_setup guide_en-us.pdf

It appears that your previous statement was correct about only using dedicated GPUs.

Do you have another MXM GPU to swap?