Re: HP 450 G3 - No power
Well that sucks. Any way to confirm it for certain?...
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Re: HP 450 G3 - No power
Here is a picture of the board with more details on the resistances....
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Re: HP 450 G3 - No power
Sorry about that.
Yep, 7-8 ohms on the big ones....Last edited by krayz; 08-28-2023, 05:27 PM.
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Re: HP 450 G3 - No power
[B][COLOR="Red"]Boardview --->[/COLOR][/B] [url]https://www.badcaps.net/forum/showthread.php?p=984641#post984641[/url]
[B][COLOR="Red"]Schematic --->[/COLOR][/B] [url]https://www.badcaps.net/forum/showthread.php?p=975096#post975096[/url]Re: HP 450 G3 - No power
[B][COLOR="Red"]Boardview --->[/COLOR][/B] [url]https://www.badcaps.net/forum/showthread.php?p=984641#post984641[/url]
[B][COLOR="Red"]Schematic --->[/COLOR][/B] [url]https://www.badcaps.net/forum/showthread.php?p=9750Last edited by Vesko356; 08-28-2023, 04:22 PM. Reason: Attached schematic and boardview removed and replaced with link.
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HP 450 G3 - No power
Laptop: HP 450 G3
Motherboard: DAX63CMB6C0 REV: C
History: Stopped working after a power surge (supposedly through the RJ45 port)
Issue: Does not respond to power button (power LED is on though)
What I've done/checked so far:
-Visual inspection: Board looks fine, even under scope
-Charging port and cable ok. Charging port is also ok
-Removed battery and reset CMOS
-Measured 19v rail - passes the first two mosfets only.
-Measured all the coils: only 5V present.
Fixing it is not top priority, learning is (would be nice...
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Re: Asus X550LD - not turning on
Hey. I talked to some experts, and they think so too. You disabled the onboard ram and used sticks ?
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Re: Asus X550LD - not turning on
Reflashed the bios on u2803 - same story. ram still hot. running out of ideas...
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Re: Asus X550LD - not turning on
Num lock doesn't work on usb keyboard when connected and powered on.
I can't seem to find H_DRAM_PWRGOOD on the schematic. Is it called by some other name?
U7002:
The hottest part of the board are the RAM modules...
Thanks so far
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Re: Asus X550LD - not turning on
No extra RAM modules sadly
Here are the measurements in picture form...
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Re: Asus X550LD - not turning on
big coils:
18,5v
1v
1,5v
1,7v
1,3v
i have onboard ram only
pin 30 on ram slot: 0,4v
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Re: Asus X550LD - not turning on
OK... so I bridged the MOSFET (temporarily, I'll order a new one) and plugged in the charger - the laptop would still not power on.
Then I removed the CMOS battery, pressed the power button and the laptop powered on: first and last LED power on and stay on, and the fans start spinning (yay). It works like this with the CMOS battery back in as well. I'm doing all this without the laptop battery plugged in for now.
Voltages look normal (the problem is I don't really know what did it - the charger IC replacement or the MOSFET...
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Re: Asus X550LD - not turning on
Me again, got the components and restarted my work.
I've replaced the PU8800 IC. Checked the continuity, looked good. Also replaced the surrounding resistors with new ones (with correct values).
I plugged in the battery and charger - now it wasn't only smoke ... a MOSFET burned, literally (i instantly unplugged and checked around with the microscope - no other damage visible). The MOSFET was PQ8805.
I reconnected the charger and I checked the voltage on P_CHG_ILIM_10 and it showed ~3V (without the battery),...
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Re: Asus X550LD - not turning on
OK, I've ordered a new charging IC (cheap, but it will take some time to get here i suspect).
In the meantime I'll browse around the forum and try to learn more about charging/power circuits and how they function.
One question: you said ILIM is an input. What would happen if voltage was injected to ILIM pin with a lab. pow. supply?
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Re: Asus X550LD - not turning on
Welp, that didn't go according to plan (there was smoke involved )
I removed the battery immediately, hopefully no (serious) damage.
Checked continuity from each IC pin to immediate connections and everything was OK. So I have no idea what this is all about ^^
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Re: Asus X550LD - not turning on
So I tried to reflow - no difference. Then I took the charger IC off the board.
I remasured the two resistors PR8820 and PR8819 at 100k and 300k and put them back (on the board values change, which is normal as I understand?)
Can the board be plugged in without it, since the IC controls the charging?
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Re: Asus X550LD - not turning on
I'll try reflowing the IC first. what temperature should i use?
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Re: Asus X550LD - not turning on
only had through hole resistors, so i used one of those - 14,7k
new readings on pr8820: pin1 0,2v ; pin2 3,3v
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Re: Asus X550LD - not turning on
2) 100k
3) cca 1k
4) 4,6k
5) 0,01v
pr8820 pin 1 (0,01)
pr8820 pin 2 (3,3v)
side note: the pulsating sound is coming from around this area, if that is even important.
thanks for your help so far
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Re: Asus X550LD - not turning on
Could it be a superio problem? how does one test it?
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Re: Asus X550LD - not turning on
So I've measured the values of the points in the guide and they are on average cca 0,05v lower than in the guide (this should be within spec right?).
There are only two values that have a larger mismatch:
41. U7002 BUF_PLT_RST#: 0,315v (should be 0,486v)
24. Q3002 SUSWARN#: 0.285v (should be 0,405v)
thats about it.
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