Search results

Probably corrosion under the CPU.

Hey Duke, Fans stay quiet in EFI Boot menu. They only ramp up once OSX gets to login screen. Also with a clean OSX it does the same. When battery fully charged, PPBUS only gets to 11.5V. Once unplugged its back to 12.6V. Waiting for ebay battery to test with.....other than that i've no idea.

Have you tried heating GPU as per aprendiz suggestion ?

Still not fixed this. Which means its something dead obvious, which i'm failing to see. I'm thinking this is a bad battery When its plugged in, PPBUS drops to 10.8 - 11.5V. Unplugged we are back to 12.6V. I dont keep batteries for retinas in stock, so have ordered a top case in for testing...

I should add i have PRAM & SMC reset the shit out of this laptop...

You have checked the data lines back to he GMUX right ?

Hi, I got a odd one here, i cant solve. So hoping someone has seen this before. This Laptop came in with no image. This was fixed by soldering around U8900 (i think thats the chip). However, once the laptop gets to the login screen the fans start to ramp up to full speed. I have tried a known...

You do have a schematic for this board, right ? If so you'll see U7750 produces S5 power for the MCP. Resistance to GND on the 3.42v rail is low, you could have a malfunctioning MCP.

So, what was it ?

Resistance to GND on PP3V42_G3H ? Do you have PP1V05_S5 ?

Normal reading is about 30 - 40KOhm. Have you tried to heat the MCP ?

What does U5750 area look like ? Also check R5704.

You don't measure resistance on a live circuit. Remove all power from board, set your multimetre to Ohms. Red probe on 3.42v Rail, black probe on ground. It may be 30 secs before your multimeter will give an accurate resistance reading. Depending on this reading, we can determine if your...

You could be unlucky and the short is INSIDE the board. How much power did you put through the shorted rail ?

Does SMC reset work via keyboard ? Have you power on Pin 30 & Pin 4 on J5713 ?

No splash-screen, fast fans, SMC issues (i think), kernel panics..............there is too much shit to fix. We gave up......

Doesnt work.....

If anyone wants to share their trusted source, i will be eternally grateful ;):o.

Thats the clock. If that goes out, then all signals go out of sync, causing all kinds of anomalies. Its more odd you had a intermittently working clock.

No, This is a £400 board. Send it to someone who can replace the PCH. Try get a trade rate.