Atomrepair
Member
I flashed it with a clean ME bin I got off of badcaps, put it back on the board and am seeing no difference. All pins are properly connected, all except GND sitting at ~3.3V like before.
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820-00165-A - PM_SLP_S4_L missing
- Thread starter Atomrepair
- Start date
Atomrepair
Member
Now I've tried the following:
original bios chip with two different clean ME bin's.
A different bios chip off of a donor board with whatever bios was on there.
All result in the same symptoms. Machine wont turn on and no pulse on CPU Vcore. Anything else I can do?
original bios chip with two different clean ME bin's.
A different bios chip off of a donor board with whatever bios was on there.
All result in the same symptoms. Machine wont turn on and no pulse on CPU Vcore. Anything else I can do?
You should get atleast pulsing ALL_SYS_PWRGD and other power rails, except VCORE.
If not, something else happened on the board...
If not, something else happened on the board...
Atomrepair
Member
After each swap I have done a few quick measurements to see if the situation looked the same as before. ALL_SYS_PWRG is still pulsing like before. I can go back and measure other rails, if thats important.
From now BIOS is involved to get VCORE too.
Check voltages at pins 2, 5, 6 of SPI chip.
You must get 3V atleast for short time when power up the board.
When SPI chip is accessed, by PCH or SMC, these voltages drop.
If any do not get voltage at all (0V steady) means there is a broken trace, or open resistor between SPI and PCH.
The pull-up resistors for SPI chip are inside PCH...
Check voltages at pins 2, 5, 6 of SPI chip.
You must get 3V atleast for short time when power up the board.
When SPI chip is accessed, by PCH or SMC, these voltages drop.
If any do not get voltage at all (0V steady) means there is a broken trace, or open resistor between SPI and PCH.
The pull-up resistors for SPI chip are inside PCH...
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Atomrepair
Member
All pins but GND are sitting at a steady 3.3V
Atomrepair
Member
Atomrepair
Member
Found a working 820-2936B I had lying around. It had some issues (had moisture damage and runs very slowly), but it will boot up. The pins look different on this one:
SPI_MLB_MISO
I take it that in my 00165 board there is some type of handshake thing going on that isn't being replied to?
SPI_MLB_MISO
I take it that in my 00165 board there is some type of handshake thing going on that isn't being replied to?
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Atomrepair
Member
but.. a few posts ago you said:
Did my scope pics show something to make this board go from flashing a different BIOS to troubleshooting Vcore?
Feeling bad that I dont know where to go from here again... I looked at where Vcore comes from.. U7310 and U7320.
U7320 VCC and CPU_VR_FCCM both pulse once.
CPUVR_PWM2 and CPUVR_PWM1 do not pulse, but sit at 0V and have 466kOhm to GND. same resistance on a donor board.
CPUVR_PWM2/1 are generated by U7200, which in turn requires PP5V_S0 on its VCC pin to power up. PP5V_S0 pulses, but wont stay on.
I would expect CPUVR_PWM2 to pulse just like PP5V_S0 does. I've taken a close look at U7200, but it and its surroundings look fine.
Is U7200 a suspect here or do I need a solid PP5V_S0 for this circuitry to work at all?
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Atomrepair
Member
Thanks for the assistance in this thread guys.
All in all I've tried three different bios files; two I found online and one from a donor board. Unless someone has one thats definitely worth a try I guess this is the end of the line. Learned something new, but not the most profitable of repairs
.
All in all I've tried three different bios files; two I found online and one from a donor board. Unless someone has one thats definitely worth a try I guess this is the end of the line. Learned something new, but not the most profitable of repairs
.
Atomrepair
Member
Feel free to close this one. Cause found (CPU), no fix.
Atomrepair
Member
Cancel that.. I just ran it through the UC, after that it got fan spin. Left it on for a while, switched it off and on again.. Now its just repeating short fan spins. Should I try heating it a little (to pre-reflow temp) first or UC it again?
Atomrepair
Member
I've UC'd it again and put the original BIOS chip with original BIOS on it back on the board. Getting consistent full fan spin now. I'm guessing there must've been some corrosion under the CPU after all.
CPU Vcore is now 1.7V, all other rails I was missing before (ALL_SYS_PWRGD) are back up. No gong or image on screen (internal or external). NVRAM reset doesnt seem to do anything, but it will shut off when holding the power button.
USB mouse light is flashing when connected. Still a borked CPU?
CPU Vcore is now 1.7V, all other rails I was missing before (ALL_SYS_PWRGD) are back up. No gong or image on screen (internal or external). NVRAM reset doesnt seem to do anything, but it will shut off when holding the power button.
USB mouse light is flashing when connected. Still a borked CPU?
Likely, or corroded solder ball under there. I've had a few like that on the 3330 cured with a mild PCH reflow with some flux, but wouldn't try that on the wimpy CPUs here.
Atomrepair
Member
I tried a steamy hot ~85 degrees UC bath for 30 sec like you suggested in another post here somewhere, now it won't spin the fan anymore. I'm giving up on this one, looks like its a problem under the CPU and I cant fix that.