820-2519 3v3_s3, s0, cpu_vcore

[Ryanlen2]

No liquid damage. Very clean board. Wont turn on.

G3h - 12.56V
S5_HS_COM - 12.56V
S5_HS_OTH - 12.56V
PPDCIN_G3H - 16.37V
PP3V42_G3H - 3.42V
PPVRTC_G3H - 3.3V
PP5V_S5 - 5V
PP5V_SUS -5V
PP5V_S3 - 5V
PP5V_S0 - 5V
PP3V3_S4 - 3.3V
PP3V3_SUS - 3.3V
PP3V3_S5 3.3V
PP3V3_S3 - problems
PP3V3_S0 - 0
pp3v3_T29 - .836V (line is not shorted; does this matter in this situation?)
PPVCORE_S0_CPU - 0.1V

When this came in this had no VCORE and I was troubleshooting pp3v3_s0 for Q7950 for All_SYS_PWRGD for EN on U7400. Now, I notice I keep losing pp3v3_s3. I have replaced Q7810 and regained pp3v3_s3 for about 60 seconds, fans were spinning but still no CPU_VCORE. Then soon lost pp3v3_s3 again. Im assuming if I replace Q7810 it will come back. But I am assuming I will most likely lose it again. R7975 was ripped off, and has been replaced. If I'm way off please let me know. Thanks, have a good one bro, appreciate it.

 

[dukefawks]

Why are you not checking P3V3S3_EN and P3V3S3_SS. Blindly replacing Q7810 is not using brains.
Also if R7975 was ripped off, someone already fucked with this board and anything can be wrong with it. GPU still original edge bonding? Serial number sticker on RAM slot?

 

[Ryanlen2]

Hey Duke. Not blind. I assumed because I had 3v3 on pins 2,.3 and 4 of Q7810 and nothing on pin 1 (pp3v3_s3) that Q7810 was my issue. Isnt this where it (3v3_s3) is created? Maybe Im confused. Please help me understand. GPU edge bonding is still original. No burn marks in the area. RAM sticker in tact. Resistor was ripped off as if someone had removed the board carelessly and maybe slipped with a screw driver putting it back in. Thank you Duke.

 

[dukefawks]

Oh so you have 3V on pin 3 so yeah then Q7810 would never open. P3V3S3_EN present?

 

[Ryanlen2]

Hi. Yes. I had 3v on pin 3 and PP3V3S3_EN was not present. When I remove Q7810 for a like 10 seconds and put it back on, pin 3 becomes 0 and PP3V3S3_EN is present giving me PP3V3_S3 & S0. This does not stay. After I unplug the power and plug it back in I'm back to 3v on pin 3 and PP3V3S3_EN not present. Now, even with my 3v rails being present , I still did not get CPUVCORE. Checked Q7950 and found I was only getting .361V on VMON_Q4_BASE. Though I was getting 3.3V on pin 6, 1.074V on pin 5, 1.497V on pin 7 of Q7950. All this doesnt matter because once i unplug I lose my 3V S3 rail. What changes when I remove this chip? Thanks Duke.


Update -

Q7812 (non working state)

pin1 - 0
pin2 - 0
pin3 - 3.3V
pin4 - 0
pin5 - 0
pin6 - 3.2- 3.0V. It fluctuates up and down. Mostly down.

pm_slp_s3_l and pm_slp_s4_l are missing in this state.

Thanks

 

[dukefawks]

If pin 6 is fluctuating then I bet P3V3S3_EN is doing that too, there is no other way it could happen. Is PPBUS and PP3V3_S5 stable?

 

[Ryanlen2]

I came in and pin 6 is steady now. Im not sure why it was fluctuation yesterday but it was slightly, not now. PPBUS is steady at 12.54V and 3v3_S5 is holding at 3.351V.
I removed Q7812 to check PP3V3S3_EN without it and plugged in power, fans go high and I have 3.3V on PP3V3S3_EN. This only lasted for about ten seconds, then board shut off and PP3V3S3_EN and was gone. I disconnected power and plugged back in, and the same thing occured but this time only for a couple seconds. Thanks alot. Have a good day.

PM_slp_S4_l is also gone, which is where schematic says PP3V3S3_EN comes from.

 

[dukefawks]

I honestly have no idea. Seeing as this thing was already pre-fucked it could be absolutely anything. If the RAM slot has no serial number sticker then it is a refurb board and can go in the trash for sure.

 

[Ryanlen2]

Got it working and VCORE as well, but VCORE is low. I measured at 7530 and got .765V with 4 OHM resistance to ground. I get very nervous around this area because I have fucked up before messing with the transistors. Any thoughts or suspects before I proceed? Thanks.

*L7530. Sry.

 

[dukefawks]

0.75V on Vcore is fine. USB mouse lighting up? Why is it working now all of a sudden?

 

[Ryanlen2]

Kind of discouraging. Noticed it working after replacing C7912 and R7912. Also, I got thrown off because it wasnt doing the 2 fan spin thing to let me know it was working. It would do 1 short fan spin then shut down. Then i would have to unplug and plug back in to get steady fan spin and 3v3_s3. Because I also was missing VCORE? Anyway all is good. Thanks.