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820-476-A no fan spin

F

Fanfwe

Member
Looks like there's a bit of change now.

PP5V_S5 steady
PP5V_S4 pulses
PP5V_S0 pulses
PP4V5_AUDIO_ANALOG pulses
PP3V42_G3H steady
PP3V3_S5 steady
PP3V3_S4 pulses
PP3V3_S3 pulses
PP3V3_S0 steady (That one used to have 2V between pulses, and pulses to 3.3V now this one works at 3.3V permanently)
PP1V5_S0 pulses
PP1V05_S0 pulses


Also I now get a pulse on L7310 and L7320
 
F

Fanfwe

Member
Allright. Thanks for all the help so far. I'll need to source U8005 and it will probably take me some time. Will update you once I have a new chip soldered. Hopefully it's not the PCH, fingers crossed (although I don't have much hope anymore)
 
F

Fanfwe

Member
Allright, coming back to this board. Sorry for the long delay.
I did replace U8005, and no luck. I still don't get the PM_PCH_PWROK and PM_PCH_SYS_PWROK signals from those two logic gates.
I saw a video where Louis "sodomized" a board of the same type, and where he removed U8005 and put jumper wires directly between PP3V42_G3H and those two signals. I tried that too. The board doesn't boot.
As a last attempt, I removed the ROM flash in order to reprogram it with a clean ME dump. It appears that the fan spins while the ROM is off the board, but well, without a firmware, it doesn't mean it actually boots.
After I solder the ROM back on the board, after reflash, the board still doesn't start. It draws 20mA from the power supply, and every 5 seconds or so, spikes to around 160mA for a very short time and goes back down. So it tries to boot, but fails.
Is this time for me to call this a donor board ?
 
F

Fanfwe

Member
Oh sorry, I must be tired.
I actually meant U1950.
I did replace U8005 as you suggested, and that didn't help.
Then, since I saw no PM_PCH_PWROK and no PM_PCH_SYS_PWROK on U1950, I removed it and bypassed it with a juper wire to "force" PRWOK signals (since all my power rails actually look good when they pulse. I was kinda thinking that maybe the circuit that checks the power rails is bad, and so the system turns the rails on, sees that PWROK signals don't come up, so system turns all rails off right away, and then tries again 5 seconds later. Is that what would happen if the voltage sensing stuff around Q8150 doesn't work properly ?).
 
F

Fanfwe

Member
Pin 2 - CPUVR_PGOOD_R: 1.9V
Pin 8 - PP3V42_G3H: 3.42V
All other pins read 0V

With that chip back on the board, instead of the bypass wires, the board doesn't try to start anymore. I have a steady 0.025A current reading on my power supply, no more spikes to 160mA every 5 seconds like I had when I forced the PWROK signals high.
 
2informaticos

2informaticos

Administrator
Staff member
"With that chip back on the board"
Do you mean U8005, or U1950?

No pulse at all at pin 7 of U1950, when you get pulse at PM_SLP_Sx_L signals?
 
F

Fanfwe

Member
I mean with U1950 back on the board. (And it's a good one for sure, I have tried it on another board right before)
No, I don't have a pulse on PM_SLP_Sx_L signals anymore. I don't see the board trying to start anymore. It draws 25mA and that's all.
All I have is the G3H and the S5 rails. Other stuff doesn't even pulse.
 
2informaticos

2informaticos

Administrator
Staff member
No pulse for sure when you trigger SMC_ONOFF_L to ground?
If you get pulses w/o U1950, you must get them w/ it too.
Use an o-scope, helps to catch fast pulse.
 
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