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You were correct sir. U5110 (W/TPAD) 1: 3.42V 2: 0V 3: 3.42V 4: 2.8V 5: 3.38V 6: .567V 7: 3.41V 8: 3.3Vv U5110 (No TPAD) 1: 3.42V 2: 0V 3: 3.42V 4: 2.8V 5: 3.38V 6: 3.4V!!! 7: 3.41V 8: 3.3V So it must be either the TPAD or the cable. Time to play a little "process of...

I have on the bench an 820-3437 with a power on issue. The customer told me that it would charge but not turn on so they replaced the battery. They said the owner used it for a bit but it started acting up so they replaced the battery again. I measured the G3H rails with only battery plugged in...

No still no image or chime.

Oh I did UC this board. I think it originally had no MS light so I reballed the SMC.

So I have an 820-3115 that has no image or chime. Iv'e checked all of the rails on the power aliases page in the schematic and found the only one that seems to be missing is PPVCORE_S0_AXG. it measures 0v. Shouldn't it be 1.05V?

Yeah I tested the board and can confirm it was only a backlight issue before I changed U7701. I'll have to to see if I can get someone to clean the ME for me. I'll try with my MEDUSA first. the last time I tried it didn't work.

So I have an 820-00165 that I pulled out of my "rabbit hole" box. I'm pretty sure it just needed a new U7701 and some solder mask repair. So I put a new U7701 but not it draws a steady 450mA but no chime amd no image. The only corrosion found was in the area of U7701. Now I am stuck with an LB...

Thanks I will try to reflash back up first.

I don't think I overheated it, and the BIOS wrote back to the chip without errors. I used a soldering IRON to put it back on the LB. I have one of those clips that clamps over the legs so I do not have to take it off the board again but I need to build a header or something for the other end to...

So Microchip brand?

It is a SST I beleive.

By discarding BIOS mod, are you saying I should flash the original back to chip and then retry?

On the bench I have an 820-2796 that had an EFI lock on it. I desoldered the EFI IC, soldered it to a little breakout board and backed up the BIOS then removed the EFI lock. Before I did this the laptop did not kernel panic and now it does randomly, and after every time I shut down after it...

Is that before triggering SMC_ONOFF_L? If so, I measured .33V

Thank you piernov. I replaced C7771 and it seems to be working well. I let it cool for an hour and it still turns on. Just out of curiosity, are there any measurements that can be done to confirm this is a fix either way? I understand that the proof is the computer is now running, I was thinking...

I believe this board is one of the ones prone to the classic C7771 failures. I'm getting 330ohms to GND but do not have another board for reference.

So on the bench I have an 820-2532 with a strange issue. It is usually drawing 40mA and not powering on, so I checked power rails and am missing PP5V_S3. I removed L7220 and injected 5v to mimmic the 5v rail coming from U7201 and then triggered SMC_ONOFF_L and the board started. I removed the...

On this machine the only options are AFPS. I can format it on my Pro as OS Extended (Journaled) if needed. I'll format one of my drives.

I actually see the drive, it says it is "Uninitialized" I wonder if that means it is new. I tried one of my SSDs with High Sierra but it still gave a ? folder.

So. I have an 820-2850 on the bench that does not see the internal hard drive. I checked signals around J4501 and am getting 5v at L4500. I have tried 3 known good cables, and 3 different known good hard drives. Just get a flashing ? folder. Should I be looking for data signals now?