MacBook Air 1466 820-3437-B Dead no fan spin

[mferna14]

Hi all, working on a MacBook Air 1466 820-3437-B. It had liquid spill on the BIOS chip U6100, U1950 & corrosion on 2-3 passive components. I cleaned the board. After replacing I got all voltages 3.3 & 5V, 1.5V but the fan does not spin & no display/image. I re-programed the BIOS but still no luck. I checked further, ALL_SYS_PWRGD signal is missing & according to the Schematics, this chip U8160 generates the PWRDG but this chip is NOT present on the board. From where is this signal coming from?? Thank you

[piernov]

Re: MacBook Air 1466 820-3437-B Dead no fan spin

https://logi.wiki/index.php/ALL_SYS_PWRGD

[mferna14]

Re: MacBook Air 1466 820-3437-B Dead no fan spin

Thank you so much "Piernov" for the tip, will surely try tomorrow & let you know.

[mferna14]

Re: MacBook Air 1466 820-3437-B Dead no fan spin

There was a corrosion on U1970 & this is why I was not getting the MEMVTT_PWR_EN 3.1 volts. Now all works. But why does this logic board turns on after a while. I put in the Magsafe 2 Jack & at first no Green light & then after about 30~50 sec the light automatically turns to green & the logic board turns on without any problem, battery charges well & there is 100% display. When there is no light even on the fuse F7140 & Coil L7130 no voltages at all, I re-flowed the SMC & try with another DC-in Board, but did not make any difference. This happens continously when the power jack to removed & put back on. Why is this delay & why is this happening??? any tips please!!!

[Askic]

Re: MacBook Air 1466 820-3437-B Dead no fan spin

I don‘t have MBA 1466 with that particular motherboard, but I have seen many times (on youtube) that normal boot for 3437 board is (when connected to the magsafe2 charger) fan spin/stop/spin/stop and then finally spin and normal boot process. It takes some time, but not sure about 30 to 50 seconds. It looks like too much.

[piernov]

Re: MacBook Air 1466 820-3437-B Dead no fan spin

Check with fake Magsafe or power supply if it turns on right away.

[mferna14]

Re: MacBook Air 1466 820-3437-B Dead no fan spin

I am certainly using a 100% Original Apple Magsafe 2 Power adapter. This same Power adapter turns on other board perfectly well without any problems. I even tried it with another Power Adapter. Still the same... No idea what is happening. Now while checking I just noticed the Flex cable (821-1722-A) which connects the MagSafe power board to the Logic board when not connected, the logic board turns on without any delay. So this mean that something is going wrong somewhere with the pin signals of J9500. Any other tips will be greatly appreciated.

[mon2]

Re: MacBook Air 1466 820-3437-B Dead no fan spin

How confident are you that the magsafe 2 adapter is 100% original from Apple ? We know that we were told the same story by a high volume reseller on Ebay and they are fakes. Just saying.

When you apply this magsafe 2 adapter onto a good logic board - how long before the LEDs turn on ? Is there a delay ? If not, and the lights turn on immediately, the adapter is a fake. There is a single-wire handshake with a maxim device that should occur and then the power rails will soft start. The fake ones, just blast the logic board with hot power. We saw sparks with ours.

Would like to taser the 'designers' of these fakes using a boost circuit and use their adapter as the power source.

[Askic]

Re: MacBook Air 1466 820-3437-B Dead no fan spin

Regarding the fake Apple Magsafe2 chargers, I have made myself two "original" chargers. I have bought two faulty original chargers and took only the cable with magsafe2 connector and then I used two original Toshiba laptop charges 15V/5A to connect this cable. The electronics that is important is in the Magsafe2 connector the rest is just two wire cable. That is how I made two chargers for MBA 1466 (since they use 14.65V).

Regarding your original problem, did you try with another IO board flex cable (821-1722-A)?

[mon2]

Re: MacBook Air 1466 820-3437-B Dead no fan spin

@Askic, measure the magsafe connector pins on your homebrew charger and plug in the AC.

What voltages do you read on each contact?

If you see a high voltage on any contact, then the custom charger you have built is still not following the Apple spec and is dangerous as the fakes from Asia.

The adapter must do a soft start to the max power rail only when it is safe to do so.

[piernov]

Re: MacBook Air 1466 820-3437-B Dead no fan spin

The point of trying with fake Magsafe or lab power supply is that they don't have a sleep mode.
https://logi.wiki/index.php/Magsafe_Sleep_Mode

[Askic]

Re: MacBook Air 1466 820-3437-B Dead no fan spin

@Askic, measure the magsafe connector pins on your homebrew charger and plug in the AC.

What voltages do you read on each contact?

If you see a high voltage on any contact, then the custom charger you have built is still not following the Apple spec and is dangerous as the fakes from Asia.

The adapter must do a soft start to the max power rail only when it is safe to do so.

I disagree. If you cut the cable with the Magsafe2 connector from the original charger you‘ll see there are only two wires. These wires are soldered to the PCB inside the charger main casing. So the most important part is the Magsafe2 connector itself, and I used this original one. The toshiba charger provides 15 V and that‘s it, just like the original Apple charger provides 14.65V on the output (on the pcb inside the case). As long as you use original low voltage cable with MAgsafe2 connector you‘re safe, because there is electronics inside the connector, which is used from original one.
Most Apple chargers fail because of the faulty component inside the main charger casing and not because of the components inside the connector.

The main difference is this ability to have sleep mode. But the described practice above cannot be considered unsafe.
I did the same as Louis did here : https://youtu.be/B3w8nwyrdYw
except I used toshiba 15V charger instead of PSU. And this toshiba charger has all sorts of protections since it is original.

[mon2]

Re: MacBook Air 1466 820-3437-B Dead no fan spin

I disagree. If you cut the cable with the Magsafe2 connector from the original charger you‘ll see there are only two wires. These wires are soldered to the PCB inside the charger main casing. So the most important part is the Magsafe2 connector itself, and I used this original one. The toshiba charger provides 15 V and that‘s it, just like the original Apple charger provides 14.65V on the output (on the pcb inside the case). As long as you use original low voltage cable with MAgsafe2 connector you‘re safe, because there is electronics inside the connector, which is used from original one.

I disagree. Applying the head from an Apple charger onto any power supply is not creating an Apple equivalent power supply. The Apple power supply has special soft start power sequencing that enables only when it is considered to be a safe docking of the connector. Current limit your power supply and apply a screwdriver across your magsafe connector - you will see sparks. That is not safe for the real world. Apple original power supplies do not do this.

Your home brew power supply is immediately 'hot' - whether the docking to the mating connector is proper or not. Same as the fakes we unfortunately purchased off Ebay. All graphics on these adapters were cloned.

http://www.righto.com/2013/06/teardo...f-magsafe.html

[Askic]

Re: MacBook Air 1466 820-3437-B Dead no fan spin

Hello mon2,

I don't claim I have made the same charger as original one. I also understand the difference. I'd like to know how this is unsafe, since it is connected to original PC laptop charger. PC laptop chargers have short circuit protection. If I apply screwdriver there will be a spark and the charger needs reset to work again.
Pc laptops also must satisfy safety and security standards, so I cannot understand why this would be unsafe. It is not original, true, but unsafe? How?

[piernov]

Re: MacBook Air 1466 820-3437-B Dead no fan spin

The point of the Magsafe sleep mode is to:
1/ prevent sparks when plugging the Magsafe into the machine, which can accelerate the degradation of the Magsafe port,
2/ prevent creating short circuit if a metal piece shorts the pins, remember that it is magnetic so something can get stuck inside it and not necessarily trigger OCP but still cause overheating,
3/ prevent sending 14.5V-20V to the 1-wire circuit if the connector gets misaligned, and even though there is a protection on the board sometimes the 1-wire circuit still gets damaged.

Note that this has nothing to do with the original topic. I was only asking to try with a fake Magsafe because an original one will not go out of sleep mode properly if it does not measure the correct standby current.

[mferna14]

Re: MacBook Air 1466 820-3437-B Dead no fan spin

Hi all, I did the same as "Askic" did... I took a Original Hp power adaptor (19V) instead.. Cut the Magsafe 2 connector from the original Apple adapter & soldered this Magsafe connector to the Hp adapter & it all works fine. The only thing what I see it that after removing the Magsafe 2 connector, they LED stays on for a while, for about a minute or so & the turns off by iitself. Other than this, the modification works fine...I am using this on this logic board & now I am not getting the delay. Allow me to attached everything together & will report once all starts to work normal.

[mferna14]

Re: MacBook Air 1466 820-3437-B Dead no fan spin

I assembled all the parts in the notebook.. I do not get any delay with this modified Power adapter. I see the display clearly & then the folder appears. But as soon as I add in the SSD, the display goes blank. no display at all. Now this had become a challenge... I tried with another known good SSD., still the same. Now what's going on???

[Askic]

Re: MacBook Air 1466 820-3437-B Dead no fan spin

mferna, thank you for the feedback.
If I understood correctly, you used HP charger with 19 V output, and original charger is 14.65V? I know that Paul Daniels uses 18V for A1466 also, but I didn't use 19 V charger, because I was afraid that some of the input caps can go short. I know that on PC laptops, input filter capacitors are 25V, but I'm not sure about Macbooks and never tried 19V, but I'm glad it works.

Piernov and mon2 have explained what is the difference between original and modified charger. I hope piernov can help use fully understand what could be wrong on the board to cause such delay with original charger.

I know this is not original question, but I'd like to know one more thing.
If I cut low voltage cable with magsafe2 connector at about half length, there will be only two wires.
Now because of the sleep functionality of the original charger, if I measure voltage, there shoud be only about 0.6 or 0.7V and 15V would show up only after negotiation with the board. Is that right?

This is very intereseting and I see this thread as an opportunity to learn more. I hope mferna don't mind it.


mferna14, regarding the new problem with the SSD, you need to make a very detail inspectin of the SSD connector both outside on the boards (pins soldered to the logic board) and inside teh connector. I hope you have a decent microscope. It is possible that you have pins that are shorted via SSD drive.
If possible, try to boot with USB live stick (you can make one with MacOS ISO image and software such as ETCHER), boot from it and check if MBA is working OK.

[moderator]

Re: MacBook Air 1466 820-3437-B Dead no fan spin

I have similar problem.. But without WiFi card... Everything works... When WiFi card is not present... As soon as i add WiFi card.. Then laptop fan will spin but no display..i tried changing WiFi card.. Still the same problem.. Don't know what is happening!?

[mferna14]

Re: MacBook Air 1466 820-3437-B Dead no fan spin

I am trying my best to figure out the problem. Without the SSD installed, it boots up fine., no problems at all. Just hope someone figure the problem similar to ours & post the solution out here.. Eagerly Waiting.. Thanks