HP 15 LA-G078P No video

[ruletero]

Hi friends

Please help me with this laptop, it turns on without video...

Model: HP 15-db0004la
MB: LA-G078P
Processor: AMD A4

I have this laptop that powers up without video, has all of its voltages on its coils, and draws 460 mA.

No schematic, no boardview, I have been using LA-C701P schematic with kb9022 EC.

I have these measurements:

LID_SW# 3.07v (EC pin 115)
PCH_RSMRST# 1.8 v ??? (EC pin 100)
PCH_PWROK 3.3v (EC pin 32)
PLT_RST# 3.3v (EC pin 13)

Ram Measurements (in red)

DDR4 ram section voltage check list at ram slot

DDR4 operating voltage VDD (at coil )= 1.2V 1.2v
and 142 pin 1.2v

VTT/Termination voltage= 0.6V PIN 258 0.6v

VRef_CA. = 0.6V PIN 164 0.6v
VDD SPD = 3.3V PIN 255 3.3v
SDA data = 3.3V PIN 254 3.3v
SCL clock = 3.3V PIN 253 3.3v
DRAM_RST# = 1.2V PIN 108 0v ????

Other measurements

APW8868C (Ram IC) pin 10 (PG) 1.2v ( I guess is correct)
SY8286BRAC (3alw IC ) pin 9 (PG) 1.3v (LA-F486 schematic)
SY8288CRAC (5alw IC) ping 9 (PG) 1.2v (LA-F486 schematic)

I know my problem is RSMRST# (1.8v) but without boardview or schematics is very dificult to find where component is connected, also, having PLT_RST# I thought that all of the above was fine.

Could you tell me how to continue please?

I attach all the files

[mcplslg123]

Re: HP 15 LA-G078P No video

RSMRST# 1.8V is very likely correct as bios chip may be 1.8V on this mb. Your problem is DRAM_RST 0V. Check consumption on dc supply
01 With RAM
02.Without Ram.

[Techtiger]

Re: HP 15 LA-G078P No video

try a locate RC308 & find out the voltage top both sie of the RC308 feedback

[ruletero]

Re: HP 15 LA-G078P No video

RSMRST# 1.8V is very likely correct as bios chip may be 1.8V on this mb. Your problem is DRAM_RST 0V. Check consumption on dc supply
01 With RAM
02.Without Ram.

Thank you mcplslg123

sorry for the mistake... It consumes 436 mA with Ram and 425 mA without RAM

[mcplslg123]

Re: HP 15 LA-G078P No video

System is not reading Ram. check ram ic requirement as well as voltage on ram slot. Thoroughly clean the ram slots(assuming its not onboard memory). Last but not the least, try with known good ram stick. Btw, Did you flash bios??

[ruletero]

Re: HP 15 LA-G078P No video

Sorry, I forgot to tell it, yes, I have programmed bios with the oficial from HP ( I downloaded and extracted it).

Too I have checked all the ram requirements,they are higher friend, all the voltages seem fine except DRAM_RST.

And I have three DDR4 memory modules, I have checked each with without success.

[mcplslg123]

Re: HP 15 LA-G078P No video

IF you have taken all the steps, it could be bad memory controller in SOC.

[ruletero]

Re: HP 15 LA-G078P No video

try a locate RC308 & find out the voltage top both sie of the RC308 feedback

Thank you friend but I didn't find any component o resistence connected to Dram_rst, only a test point...

[ruletero]

Re: HP 15 LA-G078P No video

IF you have taken all the steps, it could be bad memory controller in SOC.

Ok, I'm going to give the bad news to the client: /

thanks for everything mcplslg123

[mcplslg123]

Re: HP 15 LA-G078P No video

@ruletero, faced this on many occassions specially more on SOC platform where we dont have the liberty to replace the cpu and/or pch. So have to give up.

[mcplslg123]

Re: HP 15 LA-G078P No video

However, as a last ditch attempt, you can try to replace the pch power ic and its surrounding caps. The cmos cell must be inserted and ram stick also put in place and then power on-it may read ram properly but once you change the ram slot and/or remove cmos cell, it will start behaving same. This trick works on dell 3521 LA-9104P mb where system not reading ram is common fault(replacing the pch is the ultimate solution)-solved many cases utilising this. May help others struggling with this fault.

PS: Not sure whether it'll work or not on AMD Platform. Honestly never tried it on AMD Platform.

[ruletero]

Re: HP 15 LA-G078P No video

However, as a last ditch attempt, you can try to replace the pch power ic and its surrounding caps. The cmos cell must be inserted and ram stick also put in place and then power on-it may read ram properly but once you change the ram slot and/or remove cmos cell, it will start behaving same. This trick works on dell 3521 LA-9104P mb where system not reading ram is common fault(replacing the pch is the ultimate solution)-solved many cases utilising this. May help others struggling with this fault.

PS: Not sure whether it'll work or not on AMD Platform. Honestly never tried it on AMD Platform.

Sorry for my ignorance, in this platform what is the pch power ic? 1.05v?

[mcplslg123]

Re: HP 15 LA-G078P No video

very likely yes but need schematic to be sure.