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Old 07-15-2021, 08:12 AM   #1
grimacelord
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Default HP 15-dk LA-H462P - 5 long 3 short caps blinks.

Laptop powers on but no display. Caps lock blinks 5 long and 3 short. HP support says that means,

"5.3 (blink)

System board

The embedded controller times out waiting for the BIOS."

I flashed bios with programmer but it made no difference. I cannot find schematic or boardview for this board.

I don't have an oscilloscope, but my multimeter has a frequency reading function. I measured the RTC crystal labeled YH2 near keyboard connector and it reads 59.96Hz.

None of the large gray coils have any voltage on them.

Help? I have attached pics of board.

Last edited by grimacelord; 07-15-2021 at 08:16 AM.. Reason: attached pics
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Old 07-15-2021, 09:17 AM   #2
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Default Re: HP 15-dk LA-H462P - 5 long 3 short caps blinks.

before the Crystal, are there appropriate voltages in your voltage coils? 3.3 v, 5V, 1.05 V 1.5 v 1.2 V . which label is on the Crystal, 37620 H or 24mhz. you're measuring about 60hz this is the US city network frequency.
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Old 07-15-2021, 11:03 AM   #3
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Default Re: HP 15-dk LA-H462P - 5 long 3 short caps blinks.

Quote:
Originally Posted by Sametbey View Post
before the Crystal, are there appropriate voltages in your voltage coils? 3.3 v, 5V, 1.05 V 1.5 v 1.2 V . which label is on the Crystal, 37620 H or 24mhz. you're measuring about 60hz this is the US city network frequency.
None of the large coils have any voltage except for one near the DCIN and it has 0.3V. All other coils have no voltage.

The label on the crystal reads "A952L"

The power adapter is HP genuine and is producing 19.5DCV as intended and I can read 19.5DCV at the DCIN jack.

attaching pic of crystal and pic of the only large coil I can read any type of voltage on (marked PLB02 at top of pic #2)
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Old 07-15-2021, 11:20 AM   #4
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Default Re: HP 15-dk LA-H462P - 5 long 3 short caps blinks.

i think u have right voltage on PR303.

after start measure voltage on pin 8 on bios ic
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Old 07-15-2021, 11:31 AM   #5
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Default Re: HP 15-dk LA-H462P - 5 long 3 short caps blinks.

Does the white light come on at the power jack when the charger is plugged in
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Old 07-15-2021, 12:42 PM   #6
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Default Re: HP 15-dk LA-H462P - 5 long 3 short caps blinks.

Ok, what the hell? Now, I suddenly have some voltages I didn't have previously. See pic in below post for voltages


Quote:
Originally Posted by ktmmotocross View Post
i think u have right voltage on PR303.

after start measure voltage on pin 8 on bios ic
Pin 8 = 3.36V



Quote:
Originally Posted by SMDFlea View Post
Does the white light come on at the power jack when the charger is plugged in
Yes.

Last edited by grimacelord; 07-15-2021 at 12:56 PM..
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Old 07-15-2021, 12:56 PM   #7
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Default Re: HP 15-dk LA-H462P - 5 long 3 short caps blinks.

Here. I marked the locations on this picture where I am receiving voltages. These are are measurements taken at coils except for the one cap which is 19.7v and the pin 8 of the BIOS. Hopefully this helps better explain.

Also, question about measuring the crystal. Do I need to measure it while the laptop is plugged into power AND powered ON?
Attached Images
File Type: jpg IMG_MJL_☣️-Night-Owl-🦉_20210715_141352165.jpg (412.4 KB, 10 views)

Last edited by grimacelord; 07-15-2021 at 01:00 PM..
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Old 07-15-2021, 11:15 PM   #8
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Default Re: HP 15-dk LA-H462P - 5 long 3 short caps blinks.

You have missing VCore. Check why no voltage is generated on PCH power coil(located near PLZ1-the smaller coil). Without pch power, vcore will not come up. However, i'm assuming that coil near PLZ1 is indeed pch power coil based on experience and i may be wrong. There must be a controller near to that coil which will generate this voltage and you need to check its requirement.

Meanwhile do check resistance(in Ohms mode and not in diode mode) on Vcore & PCH power coil and post here.
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Old 07-16-2021, 07:07 AM   #9
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Default Re: HP 15-dk LA-H462P - 5 long 3 short caps blinks.

Quote:
Originally Posted by mcplslg123 View Post
You have missing VCore. Check why no voltage is generated on PCH power coil(located near PLZ1-the smaller coil). Without pch power, vcore will not come up. However, i'm assuming that coil near PLZ1 is indeed pch power coil based on experience and i may be wrong. There must be a controller near to that coil which will generate this voltage and you need to check its requirement.

Meanwhile do check resistance(in Ohms mode and not in diode mode) on Vcore & PCH power coil and post here.
The smaller coil labeled "PLA1" that we think could be PCH power has an Ohm reading of 0.5 ohms

The three larger coils that we're assuming are VCore have an Ohm reading of 0.5 ohms also.

Attaching a pic of PCH/VCORE area if it helps
Attached Images
File Type: jpg IMG_MJL_☣️-Night-Owl-🦉_20210716_125409193.jpg (897.1 KB, 8 views)
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Old 07-16-2021, 10:55 AM   #10
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Default Re: HP 15-dk LA-H462P - 5 long 3 short caps blinks.

Quote:
Originally Posted by mcplslg123 View Post
You have missing VCore. Check why no voltage is generated on PCH power coil(located near PLZ1-the smaller coil). Without pch power, vcore will not come up. However, i'm assuming that coil near PLZ1 is indeed pch power coil based on experience and i may be wrong. There must be a controller near to that coil which will generate this voltage and you need to check its requirement.

Meanwhile do check resistance(in Ohms mode and not in diode mode) on Vcore & PCH power coil and post here.
It just occurred to me that perhaps you want to know the resistance to ground on VCore and PCH. I measured across each coil. Oops.

New measurement resistance to ground in ohms mode:

The small coil that we think may be PCH power: 14 ohms
The three coils we think are Vcore are all 2.6 ohms
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Old 07-16-2021, 11:14 AM   #11
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Default Re: HP 15-dk LA-H462P - 5 long 3 short caps blinks.

The power controller nearby to the coils seems to be an OnSemi NCP81215. I'm assuming this should be providing PCH power judging by the datasheet: https://www.onsemi.com/pdf/datasheet/ncp81276-d.pdf
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File Type: jpg pchpower.jpg (2.17 MB, 7 views)
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Old 07-16-2021, 11:58 AM   #12
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Default Re: HP 15-dk LA-H462P - 5 long 3 short caps blinks.

I took some measurements of the NCP81215 controller. I'll be honest, I'm not 100% sure which of these pins are important, but I checked what seem to be important by their names.

Pin 39 PWM_VID - 0V
Pin 38 PGOOD - 1.27V
Pin 36 EN (enable?) - 0V
Pin 33VCC - 1.05 V

Pin 11 PWM/PHTH4 - 1V
Pin 10 PWM/PHTH3 - 0
Pin 9 PWM/PHTH2 - 0
Pin 8 PWM/PHTH1 - 0

I am not very familiar with what all of these pins are. I know the schematic gives a description of each one. A few of them I recognize like pins 34/35 SCL/SDA are data lines. Pin 29 is FB or "Feedback", but some of these others I am not sure what exactly they do, even after reading the description

The fact that the enable pin seems to not be outputting could that be my issue? I checked for shorts on the data lines and there are none.

Not sure what to check here...
Attached Images
File Type: png pwm.png (75.0 KB, 6 views)

Last edited by grimacelord; 07-16-2021 at 12:02 PM..
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Old 07-16-2021, 12:05 PM   #13
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Default Re: HP 15-dk LA-H462P - 5 long 3 short caps blinks.

PLA1 is VCCSA not PCH VCore.
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Old 07-16-2021, 12:07 PM   #14
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Default Re: HP 15-dk LA-H462P - 5 long 3 short caps blinks.

Quote:
Originally Posted by piernov View Post
PLA1 is VCCSA not PCH VCore.
Thank you. Do you have any suggestions what I can do from here given all of the information I've provided so far?

I can provide any additional info/measurements if you like just let me know
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Old 07-16-2021, 12:20 PM   #15
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Default Re: HP 15-dk LA-H462P - 5 long 3 short caps blinks.

Quote:
Originally Posted by piernov View Post
PLA1 is VCCSA not PCH VCore.
Also, I thought this was interesting as another thread on here had a the same problem and the ultimate issue was the guy was missing VCCSA voltage at coil.

He replaced PQ4012 and it solved his issue. This laptop isn't like his however, so I don't have the same component markings.

Last edited by grimacelord; 07-16-2021 at 12:24 PM..
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Old 07-16-2021, 12:28 PM   #16
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Default Re: HP 15-dk LA-H462P - 5 long 3 short caps blinks.

So if PLA1 really is VCCSA coil then I am also missing voltage on that coil just like the guy in the other thread I linked to. It seems to be fed by the component below it labeled PQA1. The markings say: "B09 A03 FMA0193". Having trouble finding it's datasheet.

EDIT: This might be the datasheet: https://datasheet4u.com/datasheet-pd...php?id=1111716

Last edited by grimacelord; 07-16-2021 at 12:32 PM..
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Old 07-16-2021, 12:44 PM   #17
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Default Re: HP 15-dk LA-H462P - 5 long 3 short caps blinks.

Do these readings appear normal? This is on PQA1 and PLA1 which apparently is VCCSA.

PQA1 appears to be a EMB09A03HP MOSFET. (Datasheet= https://datasheet4u.com/datasheet-pd...php?id=1111716 )

Here are the measurements I am seeing in pic attached
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File Type: jpg IMG_20210716_143609.jpg (368.5 KB, 12 views)

Last edited by grimacelord; 07-16-2021 at 01:00 PM..
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Old 07-16-2021, 10:33 PM   #18
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Default Re: HP 15-dk LA-H462P - 5 long 3 short caps blinks.

The reading is not correct due to missing gate voltage. This is just a dual channel mosfet. I think there should be an IC driving the gate of this mosfet. Yes PLA1 seems like VCCSA.
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Old 07-17-2021, 09:34 AM   #19
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Default Re: HP 15-dk LA-H462P - 5 long 3 short caps blinks.

Quote:
Originally Posted by mcplslg123 View Post
The reading is not correct due to missing gate voltage. This is just a dual channel mosfet. I think there should be an IC driving the gate of this mosfet. Yes PLA1 seems like VCCSA.
OK. There is an IC nearby with board marking PUA1. The IC marking is CGT.

I tested continuity and found that two of it's pins have continuity with gate1 and gate2 of the mosfet, so it seems you were right. This appears to be the IC that drives the mosfet. I checked for voltage on the two pins of this IC that has continuity with the mosfet, but there was 0 voltage.

I have no idea what this IC is that is labeled "CGT" and has a board identifier marking of PUA1???

Here is a pic to illustrate:
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File Type: jpg neww.jpg (398.0 KB, 4 views)
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Old 07-17-2021, 09:46 AM   #20
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Default Re: HP 15-dk LA-H462P - 5 long 3 short caps blinks.

Quote:
Originally Posted by grimacelord View Post
OK. There is an IC nearby with board marking PUA1. The IC marking is CGT.

I tested continuity and found that two of it's pins have continuity with gate1 and gate2 of the mosfet, so it seems you were right. This appears to be the IC that drives the mosfet. I checked for voltage on the two pins of this IC that has continuity with the mosfet, but there was 0 voltage.

I have no idea what this IC is that is labeled "CGT" and has a board identifier marking of PUA1???

Here is a pic to illustrate:
The part marked CGT is an ON Semi NCP81253MNTBG https://www.onsemi.com/pdf/datasheet/ncp81253-d.pdf

See page 91 in the LA-H501P schematic https://www.badcaps.net/forum/showth...light=LA-H501P
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