(347) 552-2258 [email protected]

820-3023 not turning on

F

Fizzl92

Member
Hello,
this 820-3032 is dead. I noticet that the cpu is getting slightly warm after some time (i guess thats because PPVCCSA_S0_CPU, PP1V05_S0 and PP1V8_S0_CPU_VCCPLL_R are there but VCORE_S0_CPU, VCORE_S0_AXG and PP1V5_S3RS0 are missing). I checked powerrails and came to a point where i got stuck. PP1V5_S3 is the first rail thats missing. So i followed it and as far as i understand it that is how it works:
PP1V5_S3 (missing) is created by U7300. It needs DDRVTT_EN as enable (that is missing too). DDRVTT_EN = MEMVTT_EN and MEMVTT_EN needs PLT_RESET_L to be present at Q2810. PLT_RESET_L is also missing.
Here it confuses me. As far as i know VCORE comes up first and PLT_RESET_L after that as the CPU creates it. VCORE is missing on this board and ALL_SYS_PGOOD enables VCORE. But ALL_SYS_PGOOD needs PP1V5_S3 (the missing rail from the beginning) and i am back where i startet.
So there is some point where i didn?t understand the power on sequence correctly...
 
2informaticos

2informaticos

Administrator
Staff member
You made a wrong assumption.
PP1V5_S3_P1V5S3RS0 and PP1V5_S3 is not the same thing!
The second one comes from the first one, through Q7801 (controlled by U7801).
And its enable signal is P1V5CPU_EN.
DDRVTT voltage appears last, when CPU really need to read/write DDR.

Check if R7402 is OK.
 
F

Fizzl92

Member
Thank you.
R7402 iscorrect 91.1 kOhm (should be 90.9 kOhm)
U7801 has no voltage at pin 1 (VIN) and pin 5.
C7205 pin 1 is not connected to C7801 pin 1 as it should be (not beeping). So i think that that could be one problem here as these two should be directly connectet according to BV and schematic.
So i guess i need to run a wire there.
PP1V5_S3_P1V5S3RS0_FET is missing completely and shorted to GND (C7345 pin 1 beeping and just 4 Ohms to GND. And the resistance of my probes is already 3 Ohms...). Should i inject 1 V (max.1.3 V if nothing happens) there and pray that something heats up?
 
2informaticos

2informaticos

Administrator
Staff member
So you have corroded 5V_S5 trace; fix that.

PP1V5_S3_P1V5S3RS0_FET comes from L7330
You didn't mention it as missing before; also broken trace?
Short on DDR voltage now???
Lift L7330 and see where the short remains.
 
F

Fizzl92

Member
I ran a wire and not the 5V make it to U7801.
I am still a bit confused. Sorry for that dumb question but according to page 7 PP1V5_S3_P1V5S3RS0_FET = PPDDR_S3_REG = PP1V5_S3. And PP1V5_S3 is the missing rail. So i still didn?t got that right...
I lifted L7330 and the short is on pin 2. Pin 1 is ~ 160 Ohms so no short there...
 
2informaticos

2informaticos

Administrator
Staff member
Looks like shorted CPU; less possible to be RAM, or a capacitor.
You can try injecting voltage (NO more than 2V).
Remove heatsink, to detect if CPU heats.
You may need to give it time; as the injecting current will be low probably...
 
Last edited:
F

Fizzl92

Member
I injected voltage but i cant find anything heating up except my power supply cables after some time. I set it to 1.5 V and 5.3 A (max) and if i turn it on voltage drops to 0.7 V and current stays at 5.3 A cause its current limited. CPU and PCH stay cool as metal. Nothing really gets warm... Resistance is still as low as resistance of my multimeter probes. should i raise the voltage while power supply is on as is drops down to 0.7 V?
 
2informaticos

2informaticos

Administrator
Staff member
You must log in or register to reply here.
Top