Old intel Core i7 dead/shorted ?

[Ferd]

so I’ve had this cpu laying in a box for about a year now because I think I shorted it during a motherboard diagnostic, I have already replaced it with a similar 4800mq and I am posting this to see if anyone knows how to go about diagnosing a cpu , I am not sure if it’s dead or not, and need more information on how to properly check it ...

I have checked the capacitors around the die and they’re all reading a dead short , (0 Homs) , I don’t want to risk putting it in a working device because I am not sure how safe is that (don’t wanna kill another motherboard lol) ....

So isit possible that the cpu is fine and that’s it only one or a few caps that are shorted ? Or isit gone ?

 

[R-T-B]

Aren't caps SUPPOSED to read a dead short? They aren't resistors...

 

[Ferd]

Aren't caps SUPPOSED to read a dead short? They aren't resistors...

No not really, they have an internal resistance that’s very low ...
In a cpu they are not suspended in air or isolated from other components so you’re actually reading an equivalent resistance rather that a per-component resistance.
There are actually pre-determined values that should be seen when measuring on a working cpu , i just can’t find those values for the 4800mq to compare to my readings.

I am using the “continuity mode “/“diode mode” not the “resistance mode “ as that’s the way to go about finding short circuits ....
It’s probably dead , I just wanted to see if there’s something to learn here ,

 

[R-T-B]

No not really, they have an internal resistance that’s very low ...
In a cpu they are not suspended in air or isolated from other components so you’re actually reading an equivalent resistance rather that a per-component resistance.
There are actually pre-determined values that should be seen when measuring on a working cpu , i just can’t find those values for the 4800mq to compare to my readings.

I am using the “continuity mode “/“diode mode” not the “resistance mode “ as that’s the way to go about finding short circuits ....
It’s probably dead , I just wanted to see if there’s something to learn here ,

Thanks. If nothing else I just learned something new.

 

[delshay]

To confirm you have a dead CPU you need to power it up with a external bench power supply with less than 1v & not too much current. ..If the CPU core heats up & gets too hot to quickly core is dead. If it''s a single capacitor you be able to detect this with your finger ie it will be very hot. Capacitors do go faulty but it's somewhat rare on a CPU but most users including repair technician see a short & assume it's faulty without checking on-board capacitors. Let's face it, if I see a short on CPU, I don't bother to check the capacitors, I just assume the core is dead.

 

[Ferd]

To confirm you have a dead CPU you need to power it up with a external bench power supply with less than 1v & not too much current. ..If the CPU core heats up & gets too hot to quickly core is dead. If it''s a single capacitor you be able to detect this with your finger ie it will be very hot. Capacitors do go faulty but it's somewhat rare on a CPU but most users including repair technician see a short & assume it's faulty without checking on-board capacitors. Let's face it, if I see a short on CPU, I don't bother to check the capacitors, I just assume the core is dead.

Yeah , I agree it’s not something worth spending time one , especially if you’re doing this for a living....
It was a question purely out of curiosity I have no intention to “fix “ this cpu .
If it was a bga one I wouldn’t even bother tbh, but since it is socketed that allows more room for play

so is there a specific pin I need to feed the voltage through? I know I can do this on a motherboard where I inject 1v and watch the current, but since this cpu is not installed in a board how would I go about voltage injection in this case ?!

 

[delshay]

Yeah , I agree it’s not something worth spending time one , especially if you’re doing this for a living....
It was a question purely out of curiosity I have no intention to “fix “ this cpu .
If it was a bga one I wouldn’t even bother tbh, but since it is socketed that allows more room for play

so is there a specific pin I need to feed the voltage through? I know I can do this on a motherboard where I inject 1v and watch the current, but since this cpu is not installed in a board how would I go about voltage injection in this case ?!

I would inject 0.6 to 0.8v if I was going to check if CPU is dead. The assumption CPU is dead is wrong. I can bet out of 100 CPU's, I can bet at lease 1% have faulty capacitors but no one is really bothering to check (including myself).

EDIT: You can inject the voltage at the inductor. This is where a dead motherboard comes handy.

 

[Ferd]

I would inject 0.6 to 0.8v if I was going to check if CPU is dead. The assumption CPU is dead is wrong. I can bet out of 100 CPU's, I can bet at lease 1% have faulty capacitors but no one is really bothering to check (including myself).

EDIT: You can inject the voltage at the inductor. This is where a dead motherboard comes handy.

I think I can my hands on a dead mobo that supports this cpu , I’ll update if I find anything , thanks for sharing the infos

 

[eidairaman1]

View attachment 218160
so I’ve had this cpu laying in a box for about a year now because I think I shorted it during a motherboard diagnostic, I have already replaced it with a similar 4800mq and I am posting this to see if anyone knows how to go about diagnosing a cpu , I am not sure if it’s dead or not, and need more information on how to properly check it ...

I have checked the capacitors around the die and they’re all reading a dead short , (0 Homs) , I don’t want to risk putting it in a working device because I am not sure how safe is that (don’t wanna kill another motherboard lol) ....

So isit possible that the cpu is fine and that’s it only one or a few caps that are shorted ? Or isit gone ?

Try in another known working motherboard

 

[delshay]

Try in another known working motherboard

Not a good idea, it may take out MOSFETS. OP already said he checked the capacitors on the CPU & it's measuring dead short, so i'm guessing he already knows what he's doing.