Search results

This is a -3476 board. Thanks !

Hi, I have an A1502 here which came in with a backlight issue. Lots of corrosion all over the board edge near the hinges, which affected the display connector as well as the EFI ROM area. I got backlight issue sorted out and the laptop now works just fine, except for one thing. It reports...

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...

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...

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...

And... yes, that was it :) Finally got some replacement U1950. And guess what, it boots :) Thanks for the help !

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...

I haven't touched the BIOS yet (need to find a SPI ROM programmer, or build one out of a Raspberry Pi and flashrom), but I inspected the board under the microscope thoroughly once more. I found an area near U1950 where there were still traces of coffee spill. Although there was no sign of...

All PP5V_S3s read 5.12V PP5V_S0 reads 5.12V PP3V3_S3 reads 3.33V PP3V3_S0 reads 3.3V PP1V8_S3 reads 1.79V PP1V5_S0 reads 1.50V PP1V2_S3 reads 1.20V PP1V2_S0_SD_AVDD12 reads 0.95V PP1V2_S0_SD_VUHS1 reads 3.33V PP1V05_S0 reads 1.05V Checked all big coils. I have power everywhere except for LCD...

OK, I used a pendrive with OSX installed. Boots fine on other apple laptops, just to be sure. On this board, I get no activity when I turn power on. Sounds bad I guess. Anything else to test before trying to reflow CPU ?

I put the board back into the topcase, with all ribbon cables attached, and now the fan spins at normal speed. Board draws 156mA. I assume the SMC wasn't happy while outside of the topcase due to missing sensors of some kind and commanded the fan to spin at full speed. So now it looks like I...

Hi, I was given a not working MBA in which coffee has been spilled. First inspection revealed a bit of corrosion next to U7200. I cleaned that, and replaced the caps and resistors involved. The rest of the board has traces of coffee, but nothing too bad and no other trace of corrosion. I cleaned...

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)

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)...

I desoldered U8005. Still no fan spin when connecting charger. Anything specific I should look at now that the chip is off the board ?

Yeah, I'm already doing those measurements with a scope, not a multimeter. So I'm 100% sure that the pulse out of U8005 is only 0.5V, not 1.05V. Unfortunately I do not have another working board I can compare this to, but on all other power rails, I'm at least in the range of kilo-ohms, if not...

So U8050 doesn't give me a pulse on the output. But the enable signal from the SMC also doesn't pulse. More interesting, I think, is on U8005. I do see a pulse out of it, but only about half a volt, instead of 1.05. I measure 175 Ohms to ground on PP1V05_S0SW_PCH_HSIO so it looks like this is...

I get a pulse on pin 7, but not on pin 3. So, I checked the other input of the AND gate on pin 6 (SMC_DELAYED_PWRGD) and no pulse there. SMC_DELAYED_PWRGD is not shorted to ground.

So I checked PP1V05_S0, PP1V5_S0, PP3V3_S0 and PP5V_S0 and I get a pulse on all of them whenever I connect charger, or pulse SMC_ONOFF_L. Special thing on PP3V3_S0 though, it actually never gives 0V. Averages at 1.94V and pulses to 3V3 when I pulse SMC_ONOFF_L

No signs of corrosion around U1950. Nothing on ALL_SYS_PWRGD. Remains at 0V even when I pulse SMC_ONOFF_L Looking at the schematic and ISL88042 datasheet, ALL_SYS_PWRGD will be pulled to ground until all 4 S0 rails are good. But my S0 rails (actually all rails from S4 and down) don't turn on...