HP Pavilion 15-p294nf no power MB DAY11AMB6E0 REV E

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Hello
I need help to repair my PC.
My PC HP does not start, no light on DC Jack LED, no power consomption (only 1,3 mA).

I don't have 3.3V.
On PU11 :
#1 EN1 0,5V
#2 PGOOD - 0V
#3 FB -0V
#4 VOUT - 0V
#5 VCC -0.5V
#6 BST -0.0V
#7 LDO - 5.36V
#8 VIN - 19V
#9 GND - 0V
#10 SW -0V

EN2 is too low to active the chip !!!
#EN2 is connected to SIO S5_ON so S5_ON is bad.

On U11 (SIO) :
#AD_AIR = 0,93V
#AD_TYPE = 0,74V
#S5_ON = 0,5V
#P11(+3V) = 0,3V
#P121(+3VPCU) = 0,5V

Signal AD_ID = 0,66V when connected to motherboard or 18,2V when disconnected. Is it normal ?



I check R294, R298 ans R304 and values are good. No shortcut for C383 and C386.

Other value on the motherboard :
+VA = 19,5V
+VAD= 19,5V
+VA_AIR = 19V




I have checked PR144, PR143 and PC66 and they are good. I don't understand why AD_AIR is too low.
It should not be 19 * PR143 / (PR143+PR144) = 2,7V ?


Motherbord schematic

[mcplslg123]

Re: HP Pavilion 15-p294nf no power MB DAY11AMB6E0 REV E

PU11-Pin7 is not LDO, its LDO Enable pin. LDO is pin5. Check resistance on pin5 of PU11 and if the resistance is high, replace PU11. It should output LDO voltage as long as VIN is there ireespective whether En1/En2 is present or not. Those will play a role when you dont get voltage on COIL after poweron.

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Re: HP Pavilion 15-p294nf no power MB DAY11AMB6E0 REV E

Hi.
Thank you very much mcplslg123 for your answer.
First you are right, pin5 is LDO on PU11.
I removed PU11 and PC198 capacitor and I mesured 2 ohms between pin5 and ground, I don’t now if the value is correct.
I have replaced PU11 and now PU11 is hot and a see 170mA consumption on my alimentation.
Now I measured 0,27V on pin1 (EN1) and pin5 (LDO).

Before replacing PU11 another times I would like to know if 2 ohms resistance on pin5 LDO is a correct value.

[mcplslg123]

Re: HP Pavilion 15-p294nf no power MB DAY11AMB6E0 REV E

2 Ohms on pin5 of PU11(LDO) is short to ground. Remove PU11 and inject voltage on pin5 and see what is getting hot. Start with 1V/1A and gradually increase the amp. If still cant feel any heating component, then increase the voltage upto 2V/5A but dont exceed then this. Do take out cpu from socket and ram from ram slot before injecting voltage.

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Re: HP Pavilion 15-p294nf no power MB DAY11AMB6E0 REV E

Thank you mcplslg123, I will try as soon as possible.
Last time PU11 was the only hot component but I will check again.
I can remove the ram but not the cpu.

[mcplslg123]

Re: HP Pavilion 15-p294nf no power MB DAY11AMB6E0 REV E

Oh yeh, its SOC-so cant be removed.

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Re: HP Pavilion 15-p294nf no power MB DAY11AMB6E0 REV E

I make test with 1V/1A and U11(SIO) is getting hot.
I will replace it but I don't know if a programation is needed.
Ref U11 : IT8987E / 1446 BXS / SC2LUA

[mcplslg123]

Re: HP Pavilion 15-p294nf no power MB DAY11AMB6E0 REV E

IT8997E is Programmable but if you use a new SIO, then probably it gets programmed from main bios on 1st boot. many people have confirmed this on forum.

[totof]

Re: HP Pavilion 15-p294nf no power MB DAY11AMB6E0 REV E

Perfect.
The component is ordered, the rest of the story in 2 or 3 weeks if all goes well...

[mcplslg123]

Re: HP Pavilion 15-p294nf no power MB DAY11AMB6E0 REV E

In the meantime,remove SIO and clean the pads on motherboard. Measure resistance again on pin5 of PU11. If resistance goes up significantly, then SIO is most likely the only problem. Else you need to inject voltage again there to findout if anything else is damaged. The mb can safely be powered without SIO and you can check whether you are getting LDO voltage stable or not.

[totof]

Re: HP Pavilion 15-p294nf no power MB DAY11AMB6E0 REV E

Hello.
I received the new SIO but unfortunately I damaged some tracks when desoldering the SIO. Now I have to find the time to repair the tracks.

[mcplslg123]

Re: HP Pavilion 15-p294nf no power MB DAY11AMB6E0 REV E

Always use good quality flux and atleast a resonable hot air gun(not hair dryer) to desolder any smd component. We all faced that kind of scenario in beginning of our carrier. I perfected the skills of desoldering and soldering a SIO by practicing on scrap boards and thats the right approach to finally jump into repairs. Now it takes me not more then 5 minutes to desolder and resolder a SIO.

[totof]

Re: HP Pavilion 15-p294nf no power MB DAY11AMB6E0 REV E

I am not a professional.
I used an 858D hot air station and AMTECH RMA-223 flux but I think the nozzle is too small, I ordered a bigger one.

[usyusy]

Re: HP Pavilion 15-p294nf no power MB DAY11AMB6E0 REV E

Always use good quality flux and atleast a resonable hot air gun(not hair dryer) to desolder any smd component. We all faced that kind of scenario in beginning of our carrier. I perfected the skills of desoldering and soldering a SIO by practicing on scrap boards and thats the right approach to finally jump into repairs. Now it takes me not more then 5 minutes to desolder and resolder a SIO.

sir when using a hot air (air 3 and heat about 400) its seems to be difficult to remove polar tantalum capacitor, how much time it usually take to be removed.

[Stevedb]

Re: HP Pavilion 15-p294nf no power MB DAY11AMB6E0 REV E

You can first lower the temperature by adding leaded solder or even low melt solder. How big is the nozzle , nozzle abouth 9 a 8 mm is perfect for this.

[mcplslg123]

Re: HP Pavilion 15-p294nf no power MB DAY11AMB6E0 REV E

With 858D, heat should be 430-435 and air presuure at 4 atleast. To remove caps i usually use my soldering iron.

[usyusy]

Re: HP Pavilion 15-p294nf no power MB DAY11AMB6E0 REV E

You can first lower the temperature by adding leaded solder or even low melt solder. How big is the nozzle , nozzle abouth 9 a 8 mm is perfect for this.

sir surely it was less than 8 mm nozzle, ok thank you

With 858D, heat should be 430-435 and air presuure at 4 atleast. To remove caps i usually use my soldering iron.

point, got it sir, thank you