Here's the voltage I got on the FETs at the board...
There's a possibility that my buck controller is faulty and it's a clock generator as well...
CLK865J02FLF....the issue is, I can't find datasheet of it...
Here's the voltage I got on the FETs at the board...
There's a possibility that my buck controller is faulty and it's a clock generator as well...
CLK865J02FLF....the issue is, I can't find datasheet of it...
The voltages look good to me, so I don't think the buck controller is bad. Only the voltage at the Source of Q10 doesn't seem right (should be the same as Q6 and Q8). But I think you just didn't measure it properly, because Q11 does appear to have the correct V_core voltage on its Drain.
Anyways, what I am more worried about is all of the KZG caps I see scattered everywhere on the motherboard. Unless you have pulled out each one from the motherboard and checked it for proper capacitance *and* ESR, there's no telling if that's the problem or not. (And also, sometimes an ESR/capacitance meter can be fooled by an electrically leaky electrolytic capacitor, so keep that in mind if you did test all of those KZG caps. In particular, anything that reads over 20% of the nominal capacitance could be leaky).
which one are the KZG caps ( what color ) ? I haven't tested them with ESR meter, I don't have it yet ....does it mean that I need to desolder them all ?
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"¡Me encanta "Me Encanta o Enlistarlo con Hilary Farr!" -Mà mismo
"There's nothing more unattractive than a chick smoking a cigarette" -Topcat
"Today's lesson in pissivity comes in the form of a ziplock baggie full of GPU extension brackets & hardware that for the last ~3 years have been on my bench, always in my way, getting moved around constantly....and yesterday I found myself in need of them....and the bastards are now nowhere to be found! Motherfracker!!" -Topcat
"did I see a chair fly? I think I did! Time for popcorn!" -ratdude747
I've measured some of KZG caps you're talking about...
Measurement in circuit...they give me value...some of them 33K, some of them ..87K...
are they bad ones ?
Well, I don't have X-ray vision so I can't give you a verdict from the comfy seat of my chair... but all I can tell you is that those Chemicon KZG capacitors do fail quite a bit, and sometimes without visual signs too.
I have a capacitance meter, it can read capacitance and impedance, but no ability for reading ESR...would it be good enough testing them ?
Impedance and ESR become close at relatively high frequeincies (around 100 KHz), so yes you can *probably* use the impedance on your meter. Speaking of which, what meter is it?
Originally posted by bianchi77
does it mean that I need to desolder them all ?
If you want to test them, YES.
In-circuit readings on motherboards are often inaccurate and/or total garbage. So remove the caps and test. Better yet, if you have good quality low-ESR replacements, just replace those KZG caps and at least be done with that part. Then you won't wonder if bad caps were the problem, at least.
Also, the black caps around the CPU appear to be Panasonic FL (4V 680 uF). Panasonic makes very good caps, but even these can go bad simply because of where they are placed - right under the CPU heatsink. If a hot-running CPU was used, they could be dried out. I recommend getting polymer caps for those positions.
Impedance and ESR become close at relatively high frequeincies (around 100 KHz), so yes you can *probably* use the impedance on your meter. Speaking of which, what meter is it?
It's atlas LC-45....it can test on 200KHz frequency...but can it be done in circuit ?
What value should I see on it ?
It's easier when it's in circuit...but I'm not sure if the value is valid, because it's connected to other components...
It's atlas LC-45....it can test on 200KHz frequency...but can it be done in circuit ?
What value should I see on it ?
It's easier when it's in circuit...but I'm not sure if the value is valid, because it's connected to other components...
Of course it is easier to test the caps in the circuit but the result you get will not be right dues to the fact that also have other components connected in parallel with the cap. You can waste lots of time doing short cut.
Why don't you just experiment by measuring spare known spec. caps with your LC-45 to see what reading you get, and then just try removing just one of the paralleled cap off the board and test it and see what you get?
Or get the same set of caps and connect them in parallel just like what are on the board and take the reading and compare to what you get with the reading on the board.
Experiment, Experiment, Experiment to see what your test equipment can really do and understand what you are testing and understand the result.
I got -155.2 mOhm + j4484 mOhm for 2 1800uF brand new in parallel off circuit...
It might be the caps on mobo are ok...but...I'll desolder one of them anyway as you said...
if u change cap and mobo did not work you can check North bridge for disconnecting from board. you can push north bridge hit sink vertically by hand and starting motherboard. better you warm a little under north bridge by hitter before pressing north bridge.
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