HP Pavilion 15-CX DPk54 LA-841p No power

[McNoobington]

Hi All,

first post on the forum, i hope i've managed to include all relevant information here.

Technical level: 20+ years experience fixing/building PC's but am a complete beginner when it comes down to board repair.

Make/Model: HP Pavilion Gaming 15-cx0511na 8300H/1050 DPk54 LA-F841P Rev 1.0

History: Client brought it in for repair, broke more than a year ago and HP/Currys gave him the runaround but was unable to fix the issue. I was unable to fix it and he didn't want to spend money on a replacement motherboard. When he said he's going to bin it, i offered some money for it's 135W charger and got the laptop with it.
Edit: I did put the board into a 99.9% isopropyl alcohol bath as i was suspecting the board might have got water. This was before i found the burnt component.

Symptom: Doesn't power on. When the charger is plugged in, the charge light comes on and it does sense if the battery is connected or not.
Upon pressing the Power-on button, the LED light under the Power-On button comes on, then goes off in 2-3 seconds. No fan spin, no coil whine, no HDD spin up. -> No joy

I fully disassembled the laptop and after spending half an hour plus visually inspecting it, I've found a burnt component.
Unfortunately, i was not able to determine what exactly it is and cannot find a board schematic anywhere.

Tools at my disposal: multimeter, hot air station, flux, (some) common sense and a little patience.

I appreciate anyone who's taken the time to read and/or comment on this.


Best picture i was able to snap with mobile:

[rediii]

Re: HP Pavilion 15-CX DPk54 LA-841p No power

https://www.badcaps.net/forum/showth...hlight=silergy

AWS*** SY8288RAC - N/D (LA-C371P)

remove chip and check, if short is gone. also check BOTH sides (high/low).

[McNoobington]

Re: HP Pavilion 15-CX DPk54 LA-841p No power

https://www.badcaps.net/forum/showth...hlight=silergy

AWS*** SY8288RAC - N/D (LA-C371P)

remove chip and check, if short is gone. also check BOTH sides (high/low).

Thank you rediii
I've literally found it 20 seconds ago. Does it mean anything that mine says AWSAAA and the results say AWS5MA?
I will do that and report back tomorrow!


nevermind, its a year code. Why the hell i didnt register earlier? damn...

[rediii]

Re: HP Pavilion 15-CX DPk54 LA-841p No power

Thank you rediii
I've literally found it 20 seconds ago. Does it mean anything that mine says AWSAAA and the results say AWS5MA?
I will do that and report back tomorrow!


nevermind, its a year code. Why the hell i didnt register earlier? damn...

good luck! maybe you have to reconstruct the copper plate underneath. i hate these chips btw. they are exploding frequently, but maybe due to automated soldering techniques

[McNoobington]

Re: HP Pavilion 15-CX DPk54 LA-841p No power

good luck! maybe you have to reconstruct the copper plate underneath. i hate these chips btw. they are exploding frequently, but maybe due to automated soldering techniques

I'm just about to read up on its functionality, but i watched enough Louis Rossman videos to believe i can actually re-solder a new chip.
As my brother would say: don't overthink, just do it with the confidence of a true idiot!

Fingers crossed, i will definitely report back on how it went!

[McNoobington]

Re: HP Pavilion 15-CX DPk54 LA-841p No power

good luck! maybe you have to reconstruct the copper plate underneath. i hate these chips btw. they are exploding frequently, but maybe due to automated soldering techniques

Oh Boy! My confidence *might* took a hit when it arrived and i've actually seen the chip IRL

Rediii or other experienced forum members, I'd like to ask for your input please:

In my mind i'd go on like this:
Set the board to the work surface and:
1. put captain tape around the chip i'm about to desolder
2. Apply the appropriate amount of flux on board
3. Set the hot air station to ??? degrees Celsius and wait 5 minutes to actually heat up properly
4. Heat up the chip and resist the urge to yank it off with a tweezer. Only once it moved i'd use the tweezer to pick up the chip.
5. Use wick to clean the surface of soldering iron. What do i do if pad looks unhealthy?
6. -optional- Pray to -insert_god- for success
7. Apply leaded? or lead_free? solder to the pad.
8. Place chip on place and heat again, hoping the flux will keep it in place and won't go flying.
9. Measure somewhere that there is no short or something? (i'm really unsure where and how, especially as i dont have an adjustable powersupply)


I will rather not rush into this as i'd really like to get it working.
Any input will be hihgly appreciated

[rediii]

Re: HP Pavilion 15-CX DPk54 LA-841p No power

Oh Boy! My confidence *might* took a hit when it arrived and i've actually seen the chip IRL

Rediii or other experienced forum members, I'd like to ask for your input please:

In my mind i'd go on like this:
Set the board to the work surface and:
1. put captain tape around the chip i'm about to desolder
2. Apply the appropriate amount of flux on board
3. Set the hot air station to ??? degrees Celsius and wait 5 minutes to actually heat up properly
4. Heat up the chip and resist the urge to yank it off with a tweezer. Only once it moved i'd use the tweezer to pick up the chip.
5. Use wick to clean the surface of soldering iron. What do i do if pad looks unhealthy?
6. -optional- Pray to -insert_god- for success
7. Apply leaded? or lead_free? solder to the pad.
8. Place chip on place and heat again, hoping the flux will keep it in place and won't go flying.
9. Measure somewhere that there is no short or something? (i'm really unsure where and how, especially as i dont have an adjustable powersupply)


I will rather not rush into this as i'd really like to get it working.
Any input will be hihgly appreciated

1. no need for kapton tape, but for plastic connectors etc.
2. the more flux, the better
3. rework station: 425 °C, half air or more (depends on rework station. membrane pump rws do not need that much air), preheat board from far away for a short perios of time (maybe 15 sec)
4. go down on the chip, look for solder get melted (going to be shiny in some way), test with tweezers (side tapping, is chip moving?)
5./6./7. clean pads with wick (clean with isoprop.), resolder with LEADED solder and flux
=> check pads on mobo (reconstruct copper plate if necessary, maybe with thin solder wire), check components for short (diode mode or resistance mode, multimeter. just google how to measure with those settings please)
8. put leaded solder on chip with the help of flux (don't put too much heat on ic!). resolder chip with less air first. if you are doin it right the chip will reposition itself by adhesion
9. visual inspection
10. resolder all pads on the sides, check for bridges etc.
11. measure again for short
12. clean area
13. test board

=> REMEMBER CHIP POSITION and even new chips could be bad!