Hp 15-ca2003ca DAG7BDMB8F0 turns on & shuts off

[mferna14]

Hi all, I am working on Hp 15-ca2003ca (MB DAG7BDMB8F0 REV:F). The problem was totally dead. Upon diagnostics, there was a burnt SY8286BRAC. I replaced it with another one. Now the WHITE LED on the DC-in jack glows & when the main battery is installed, the status of the LED changes to Orange. But when I press ON/OFF button, I see the power LED glows for a sec & then shuts off. Same happens when I press the ON/OFF button over again. I just put the Meter leads on the 3.3/5V coils & the meter shows that these both volts are generated & then in a sec. goes away. I re-programmed the BIOS too, no luck. There does not seem to be any short on the motherboard. Any repair tips will be greatly appreciated. Thanks in advance

[mcplslg123]

Re: Hp 15-ca2003ca DAG7BDMB8F0 turns on & shuts off

Ad_id??

[mferna14]

Re: Hp 15-ca2003ca DAG7BDMB8F0 turns on & shuts off

As usual thanks for the reply "mcplslg123". The AD_ID is "zero" volts. Out here I think it should be 3.3v. But the battery charges well & the DC-in jack LED glows both in WHITE & ORANGE. Once thing more I removed the 1.8V coil going to the CPU, & now it stays one for almost a minutes or so & then shuts down & then starts again by itself. & because of this status, the 3.3v chip gets very hot. Near the Audio Chip ALC3258-CG, the meter show 4 tiny ceramic caps shorts, the rail is of +5V_AVDD & +1.8V_AVDD, can't even tell where the component are location as there is NO marking on the board at all. I removed all 4 ceramic caps physically & tested them, all are ok but the lines is shorted. Boardview would surely help. What are these power rail for???

[mcplslg123]

Re: Hp 15-ca2003ca DAG7BDMB8F0 turns on & shuts off

When 1.8V coil is removed, vcore and gfx will not rise so mb will be in a boot loop trying to recover those rails. It seems something is wrong in cpu requirement and/or bad soc. Try mildly heating on the back side of SOC and put the 1.8V coil back. This will rule out dry solder joints under SOC. be careful not to overheat. I prefer heating around the soc and not directly on it.

[mferna14]

Re: Hp 15-ca2003ca DAG7BDMB8F0 turns on & shuts off

Nice Tips & troubleshooting techniques... You know very well how hard it is to re-flow the SOC, EVEN heat is required to balance the chip on all side or it will raise from one end. I will just try to do the sides of the chip. Maybe might help. Thanks will try it & inform you...

[DanielDacko]

Re: Hp 15-ca2003ca DAG7BDMB8F0 turns on & shuts off

Please don't randomly reflow SoC. Do you have proper output (3.3V) on pin 17 of the changed SY8286BRAC? Also post resistance to ground on that rail (+3VPCU). Since you mentioned that this IC is overheating, that not necessarily means that the IC is damaged, but something is overloading it, which could be a short or low resistance on the +3VPCU line.

Perhaps this leads to nowhere, but it's worth checking before reflowing or doing something that extreme.

Here is picture of the IC pinout to avoid losing time searching for pin 17.

[mcplslg123]

Re: Hp 15-ca2003ca DAG7BDMB8F0 turns on & shuts off

I prefer reflowing the soc in my bga station. that never damages the chip and rules out dry ball joints. Dry ball joints under soc is frequent and common problems in most of the 4th gen onwards soc. It can be done with a heat gun purely for testing purpose but heating around the soc and not directly on it. This never damages a SOC.

It is worth paying attention to @danieldecko's suggestion

[mferna14]

Re: Hp 15-ca2003ca DAG7BDMB8F0 turns on & shuts off

Thanks for the help "DanielDacko" & "mcplslg123"., The voltage on Pin 17 of chip SY8286BRAC is 3.3v which seems to be right. Yes I was not going to do the re-flow UNLESS & UNTIL very nesessary, because when I removed the 1.8V coil, still the chip SY8286BRAC was turning hot when the motherboard was turned ON for a while, assuming that before the SoC some other component might be shorted. The resistence from GND to both the coils 3.3v is 4.2Kohms & the 5V coils is 11.52Kohms respectively. It's looks like the resistence is not right on the 3.3V rail. Beside this nothing is getting hot. If I inject continous 3.3V, where should I attach hot wire to? As before I mentioned that near the audio chip ALC3258, 4 tiny ceramic caps (assuming 10u 6.3V) are showing shorted. Removed all 4 of them but that rail still shows shorted. I think the rail is of +5V_AVDD & +1.8V_AVDD. Since no boardview & no marking of any component on the motherboard, cannot confirm this.

[DanielDacko]

Re: Hp 15-ca2003ca DAG7BDMB8F0 turns on & shuts off

Don't inject voltage yet. What is the voltage and resistance on 1.8V coil? If you suspect that +5V_AVDD and +1.8V_AVDD are shorted, try removing ALC3258 (can't believe that no boardview exists with this chip or any kind of datasheet with pinout) and see if the short is gone. This is logical step because they both go to the ALC3258 on pins 20 and 40. I know it is PITA to do this, but without boardview, there isn't much to do. Do you have lab psu?

[mferna14]

Re: Hp 15-ca2003ca DAG7BDMB8F0 turns on & shuts off

Thanks DanielDacko, there is voltage like any normal motherboard 1.8v & goes away within 3 ~5 seconds. Same happens with the 3.3V & 5V., meaning all voltage are generating normal till it reach the shorted component & then reset again. I did removed the ALC3258, the short was still present. Wish I had the boardview, even NO component markings on the motherboard???? How rude hp can be (:- Just figuring out by hit & try method. The resistence between the GND & 1.8V coil is 35ohms which might be ok for this type of SoC. Yes I do have a bench PS.

[DanielDacko]

Re: Hp 15-ca2003ca DAG7BDMB8F0 turns on & shuts off

If you can confirm short on pins 20 and 40, inject 1V on those rails to see what heats up.

[mferna14]

Re: Hp 15-ca2003ca DAG7BDMB8F0 turns on & shuts off

I will do so.. I think 1V is enough. Thanks