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chbalnuweit replied to HP 17-cn0234ng - RAM and VCORE voltage missing

in Troubleshooting Laptops, Tablets, and Mobile Devices

03-13-2025, 05:09 AM
Thank you for the info about the voltages order.

I tried a different BIOS from this site but its still the same behavior. Then I cleaned the ME on the original BIOS and still got the same behavior. So I dont think it is related to the BIOS.

I tried different RAM and no RAM at all. Always the same behavior:

When plugging the power, the board draws about 35mA for about 5 seconds and then drops to about 10mA and stays there. When I trigger the powerbutton, the board jumps to 50mA immediately and stays there. No fluctuation nothing.. very strange.

...

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chbalnuweit replied to HP 17-cn0234ng - RAM and VCORE voltage missing

in Troubleshooting Laptops, Tablets, and Mobile Devices

03-12-2025, 02:17 PM
As I mentioned in my initial post, I checked all the coils and they are fine. But thank you for your input!
I couldn't diagnose further since I was out sick last week.
I might look at the board again tomorrow.
Any more ideas?
What can cause RAM voltage and Vcore to be missing?
Should RAM voltage come up first or Vcore first?

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chbalnuweit started a topic HP 17-cn0234ng - RAM and VCORE voltage missing

in Troubleshooting Laptops, Tablets, and Mobile Devices

03-07-2025, 05:21 AM
HP 17-cn0234ng - RAM and VCORE voltage missing

Hi all,

I got an HP 17-cn0234ng and I am hitting a wall diagnosing it.

When I first got it, it wouldnt turn on at all and no lights were active.

I found a shorted capacitor on the 3.3V powerrail near the lid sensor. Once I removed the shorted capacitor, the power and charging light on the DC connector started working and the Laptop reacted to the powerbutton.

When I press the powerbutton, current consumption goes up to about 50mA and just stays there. Chipset and 3.3V regulator getting a bit warm under thermal camera, but not really noticeable...

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chbalnuweit replied to Motherboard schematic VLAD10-6050A3261101-MB-A01 (A1) For HP Laptop 17-cn

in Schematic Requests ONLY!

03-03-2025, 02:56 PM
Hi all,

I'm am looking for schematics for HP 17-cn0234ng (Motherboard 6050A3261101)

So I got a Laptop with no sign of life. No light, no reaction to power button but 4mA of current draw.
Main power rail was present but all other voltages where missing. Coils measured ok.
I located 3.3v regulator and injected low voltage and found a heat spot near the lid sensor. I could narrow it down to a resistor that was getting hot. I removed it and it measured around 60ohms. No clue what it is doing or if that's the right value even. So schematics would help.
...

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chbalnuweit replied to Fujitsu U748 (Touch) series serial fault

in Troubleshooting Laptops, Tablets, and Mobile Devices

10-15-2024, 06:09 AM
You just saved my day! :-) I could safe my u758 by reflowing those three CPU mosfets!...

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chbalnuweit replied to Hp elitebook 745 g3 (AMD) bios password

in BIOS Requests ONLY!

02-21-2024, 06:09 AM
The 745 G3 has to chips (16MB and 8MB) 16 MB should be the BIOS, but what does the 8 MB chip do? Is it EC firmware?
Whenever I just flash the 16 MB chip, there is a message that BIOS version missmatch and old BIOS is restored from EC. Any idea how I can fix this?
According to my research the Novoton NPCE586HA0MX is not programmable. So does it have an external eeprom?

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chbalnuweit replied to HP Elitebook 745 G3 BIOS help

in BIOS Requests ONLY!

02-16-2024, 02:28 PM
Never mind guys. I fixed it. After another inspection I found a knocked off resistor. It must have gotten loose while replacing the DC IN Mosfet and then fell off at some point.
Laptop is working again :-)

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chbalnuweit replied to HP Elitebook 745 G3 BIOS help

in BIOS Requests ONLY!

02-16-2024, 09:40 AM
Hi all,

I have a now dead HP Elitebook 745 G3.

It had two bad DC-IN Mosfets which I replaced. After that Laptop was starting again and I got post. Next day I wanted to continue and tried starting laptop without battery. All i got was white blinking light and no screen. I checked 19V ,5V and 3.3V power rail and all are present. So I tried starting laptop on battery and it booted right away but it didnt charge.
So I kinda have a feeling it might be a frozen BIOS.

Unfortunately so far I only have experience with Intel BIOS, cleaning ME region etc. This...

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chbalnuweit replied to HP 840 G5 Shorted Audio IC

in Troubleshooting Laptops, Tablets, and Mobile Devices

11-20-2023, 07:56 AM
Re: HP 840 G5 Shorted Audio IC

Hi, thank you for looking into it :-)

I saw these two pins as well but according to the schematic Pin 26 is HP_OUT_R_R and Pin 27 is PORTM_MONO and not connected to anything.
I tried to remove the bridge with my soldering iron after soldering the chip using my hot air station, but it was not fine enough to get rid of the bridge...

My next investments will definitely be a better soldering iron and microscope.. these chips are getting tinier and tinier ;-)

[B]edit[/B]: I tried again and used my iron,...

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Last edited by chbalnuweit; 11-20-2023, 08:56 AM.
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chbalnuweit replied to HP 840 G5 Shorted Audio IC

in Troubleshooting Laptops, Tablets, and Mobile Devices

11-19-2023, 01:44 PM
Re: HP 840 G5 Shorted Audio IC

Sure, here are a few phone camera photos and a screenshot of my (rather shitty) USB microscope.

Note:

Pin 4/5 are together so the bridge shouldnt matter. I couldnt get them to seperate......

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chbalnuweit started a topic HP 840 G5 Shorted Audio IC

in Troubleshooting Laptops, Tablets, and Mobile Devices

11-19-2023, 12:12 PM
HP 840 G5 Shorted Audio IC

Hi all,

so I made a stupid mistake and dropped a screw onto the motherboard while assembling it.
The screw fell right onto the battery connector area and unforunately managed to short one of the supply voltage lines of the Audio IC (Conexanct CX 7750) without me noticing at first.

After the assembly and booting Windows I noticed that there was no sound and no Audio IC detected in device manager...

I got the motherboard out again and found the Audio IC with a crater in it...
Luckily I got a donor board with the same model motherboard....

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Last edited by chbalnuweit; 11-19-2023, 12:43 PM.
chbalnuweit replied to HP Elitebook G5 (COMPUTRO-6050A2945601) Power Throttling Issue

in Troubleshooting Laptops, Tablets, and Mobile Devices

11-14-2023, 03:16 PM
Re: HP Elitebook G5 (COMPUTRO-6050A2945601) Power Throttling Issue

So I officially gave up on this one... :-(

While trying to take a few more measurements I must have shorted the ISL chip and maybe more since the charger wasn't being detected anymore suddenly after.

I replaced the ISL chip and the charger would be recognized again but charging light would cut in and out about every 500ms with a noticable ticking sound from the motherboard. Sounded like motherboard going into over current protection or so while trying to charge the battery.
...

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chbalnuweit replied to HP Elitebook G5 (COMPUTRO-6050A2945601) Power Throttling Issue

in Troubleshooting Laptops, Tablets, and Mobile Devices

11-10-2023, 04:11 AM
Re: HP Elitebook G5 (COMPUTRO-6050A2945601) Power Throttling Issue

Hi, thank you for your response!

I couldn't measure the resistors since the boardview from Gen6 does not quite match the actual Gen5 board.

However I measured the Signals CSIN and CSIP:

CSIP=19.61V
CSIN=19.13V

CSIP-CSIN = 480mV

Unfortunately I dont have the full datasheet for ISL9538H (which is on my board) but according to similar ISL95338 the delta voltage should be between 10-80mV
If the chips have same spec, it would mean...

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chbalnuweit replied to HP Elitebook G5 (COMPUTRO-6050A2945601) Power Throttling Issue

in Troubleshooting Laptops, Tablets, and Mobile Devices

11-09-2023, 11:19 AM
Re: HP Elitebook G5 (COMPUTRO-6050A2945601) Power Throttling Issue

I found a similar Elitebook 850 Gen 6 from a friend and measured more voltages of a good board:

1. id pin reading of about 0.58V is correct for this board.
2. PROCHOT pin of ISL charging IC reads about 1V on a good system.

I followed the PROCHOT pin (OCP_CHG) from ISL chip and found the schematic (see attachement)

I thought maybe the mosfet is shortet to ground and removed it. But signal was still low.

I ordered a new ISL IC and hope that the IC...

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chbalnuweit started a topic HP Elitebook G5 (COMPUTRO-6050A2945601) Power Throttling Issue

in Troubleshooting Laptops, Tablets, and Mobile Devices

11-08-2023, 01:18 PM
HP Elitebook G5 (COMPUTRO-6050A2945601) Power Throttling Issue

Hi everyone,

i am facing a strange problem with an HP Elitebook 840 G5. Unfortunatley no board schematics are to be found on this one (COMPUTRO-6050A2945601)

The laptop runs at 0.4 GHz and is always in BD PROCHOT protection. Even in the BIOS it shows 400MHz CPU clock... And same issue when booting a Live Linux. So I am pretty sure I can rule out problems with the OS. It must be lower level.
I've been researching this behavior the past 2 days and tried EVERYTHING I could find on that topic.

What I noticed playing around is that when I disable...

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Last edited by SMDFlea; 11-09-2023, 05:14 AM.
chbalnuweit replied to New Members - please post your introductions here

in Announcements & Related News

11-08-2023, 11:03 AM
Re: New Members - please post your introductions here

Hi all,

I started repairing laptops as a hobby over a year ago and gotten better with every repair. But now I am running into an issue and I cn hardly find any information.
I hope to have a helpful discussion :-)

Best regards!

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