Laptop HP Omen 15-ek0023dx DA0G3EMBCD0 REV:D no signs of life

[kamiewtype]

I got this laptop in today, will not power on. No lights whatsoever, including charge light. I'm still pretty new to component level repair so bear with me. I measured 19.5V between +VA and ground, but no voltage on +VAD, BATDIS_G, or AD_ID.

I also measured the resistance from AD_ID to ground. I got 5.2kohm with red probe on ground, and 6kohm with black probe on ground (unsure which is correct). Is this what you would expect for a 200W charger? I wasn't able to find much information but what I did find suggested that 200W charger id pull-up resistor should be closer to 100kohm.

Boardview is here, unfortunately I've been unable to find a schematic.
https://www.badcaps.net/forum/troubl...26#post3155226

Edit: Finally found another 200W charger, of course right after I made the post. With this adapter, I am getting about 1V as well as the 100kohm expected on AD_ID. I was able to measure .85V on AD_TYPE but other than that, nothing has changed as far as I can tell.

[mon2]

but no voltage on +VAD, BATDIS_G, or AD_ID.

Stop. This is of concern. This pin must emit a voltage from the adapter side and is the needle like pin inside the barrel connector. If absent, the adapter is defective. If there is voltage here but not on the board, then inspect the DCin power connector. This analog voltage (which cannot be 0v for operation) must be present and is sampled by the EC which is often a 8051 or similar microcontroller using an analog to digital converter. Based on this analog voltage, the power adapter specs are recognized by the host logic board.

On your motherboard - do you see other silk screen markings? Maybe similar to 'LA-****'? This logic board may be similar to others and can be used for guidance.

Which charger IC is onboard? Hunt for 'ISL' or 'BQ' topside markings and share full details.

Update - found the same boardview in my database. The charger IC is the BQ series @ PU8200.



Remove all power. Meter in lowest resistance mode (if manual type meter) -> measure the resistance to ground on pin # 1 on this BQ charger IC. See the top view as posted for pin # 1 location.

What is the resistance? If the resistance is low, then the main power rail is shorted and is of concern. On the internet are articles on the expected safe voltages for the AD_ID for HP. If the voltage is too low, the adapter is deemed to be under powered.

[mon2]

In following the thread with the posted BV file -> do you have a burnt component onboard as they have posted?

[kamiewtype]

Thank you for the response. I realize the issue with AD_ID having no voltage. However, I was able to find a second adapter and test it, and while it did produce a voltage on AD_ID (as included in edit), the protection mosfets still would not open.

I measured the resistance as you said and I got 10kohm/15kohm depending on direction. Don't think main power rail is shorted. As for burnt components, I don't see any, but I don't have my microscope today so I was just using a loupe. I did see a few large spots of a dark, opaque sticky residue, including some that completely covered a couple capacitors. It may be flux but I'm not sure. I'm including some pictures, although they aren't of the highest quality. I'll try and bring in my microscope so I can get some better ones.

[mcplslg123]

AD_ID at close to 1V is correct. Seems like the mb is worked upon by someone earlier. Does 19V reaches CLR? What is the voltage on pin4 of dc-in mosfets?

[piernov]

I also measured the resistance from AD_ID to ground. I got 5.2kohm with red probe on ground, and 6kohm with black probe on ground (unsure which is correct). Is this what you would expect for a 200W charger? I wasn't able to find much information but what I did find suggested that 200W charger id pull-up resistor should be closer to 100kohm.

Irrelevant now since AD_ID looks ok, but pull-up means the resistor is connected to 19V, not to ground.

[kamiewtype]

AD_ID at close to 1V is correct. Seems like the mb is worked upon by someone earlier. Does 19V reaches CLR? What is the voltage on pin4 of dc-in mosfets?

That's a good enough explanation for me. By CLR I assume you mean current limiting resistor, unfortunately I don't actually have the schematic for this board so I'm unsure which resistor that is. As for the mosfets, both are showing 0V on the gate.

Irrelevant now since AD_ID looks ok, but pull-up means the resistor is connected to 19V, not to ground.

Thank you for the clarification, that was my misunderstanding. I thought it was "pulling up" the voltage on AD_ID from ground to 1V. What would you call this resistor, other than just the adapter ID resistor?

[kamiewtype]

Hope it's alright if I bump this thread. I'm still in need of help with this machine. If there's any additional information I can provide please let me know.

[mcplslg123]

CLR is usually located just after the 2 dc-in mosfets. The gate voltage at zero on both dc0in fets means 19V is certainly not reaching CLR.
Check whether any of the dc-in fets are shorted or not?
Check resistance to GND on pin5-6-7-8 of 2nd dc-in mosfet(if clr cant be located). This will confirm whether 19V rail is shorted to GND or not.