Recent content by Naevius

With "but no image, chime, backlight and CPU activity " I mean no image, no chime, no backlight, and no CPU activity (so USB stick doesn't flash). If it would be the GPU, it would at least have backlight, right? Checked external video, not nothing.

I have a 820-2915-B board that gets in S0 state, but no image, chime, backlight and CPU activity (checked with USB stick with LED). Fans do spin (first 3 seconds on, then 3 seconds off, then stays on). Heat sink gets warm (not hot). No visible damage on the board. S0 rails like PP5V_S0 and...

This 820-3662-A board has a pulsing PM_SLP_S4_L. S5 rails are stable. Checked around the U6100, but no visible damage. Termination resistors are good. Currently I don't have a donor board for this, so can't replace U6100 to test. Any other things I could measure or try before buying a donor board?

Checked again, and short on PPBUS was still present. I guess I was too focused on the low resistance on the CPU side. I injected voltage on PPBUS again (with CPU coils still removed), now with 1.2V, which takes 2A. The GPU was getting hot. Verified by removing the heat sink, and the GPU its self...

Both coils measured double the value of the short, so seemed like short on CPU side. Removed L7401 and L7400, and short is on CPU side. Removed several caps like C7420, C7423, C1242, C1243 to be sure it wasn't that, but short remains. The resistance value also get really low (< 2 ohm) when just...

I have trouble finding the short on a 820-2879-B board. Resistance to ground on PPBUS_G3H is 11 ohm. I removed F7040, short is on the side of pin 2. A bit of (sugar-ish) liquid damage on U7500, C6960 and around R7400. Cleaned with IPA, but 11 ohm short remains. Have put 0.8V directly on...

Pin 17/18 was 600 ohms, traced down to faulty R7051, which should be 2.2 ohms, was ~600. After replacing this resistor the machine is working again. I would not have expected for a current sens issue to have this effect... so I've learned something. Thanks again for your help :)

The donor board came in. Reballed and replaced the SMC. Now the system runs on battery, but won't charge. Now also the system doesn't want to run on just the charger. With just the battery connected the system sees the battery, but when connecting the charger the light goes green, but the...

Replaced the battery, and problem solved! So somehow the battery got blocked due to liquid on the connector i guess. Anyway, thank for your help :)

I have ordered a new battery, should be here in a couple days. I checked out be2works, but the software seems outdated (Win7 32bit only). I tested the demo on a virtual machine, but even after I installed the driver it can't find the driver when starting the application. It's also pretty...

This 820-3332-A board runs fine with the charger connected, but won't run on battery. When it's booted the OS sees the battery (says 17% charged), but won't charge the battery. There was liquid damage around the battery connector. When the system boots there is 12.5V on J6950 (PPVBAT_G3H_CONN...

Yes, 3.3V on pin 1/R7805, but 0V on pin 2. So U7800 is very likely pulling it down. On page 74 of the schematic it seems all the required voltages are present to enable ALL_SYS_PWRGD, even though I find this type of diagram kind of confusing, since it's not always clear what is an input or...

Ok, I'll stop with this board then. Always feels bad when something can't really be fixed. Thanks for the info.

There is USB activity while booting. So might be worth to look at least a little further maybe? Is there a way to determine if the GPU is bad or there is no "activation signal" for the image?

Checked R7805, is 10k as it should. So is it certain that it's a PCH issue? This pretty much makes the board unrepairable, right?