macbook A1466 no green light

[sassan]

Hello,

i have a macbook air A1466 820-00165A with no green light,when trying to turn it on the fan spins for short time then stops ,no display.

Any suggestion please.

Thank You.

[mon2]

Re: macbook A1466 no green light

1) Is the adapter an Apple original? Is it a known good working adapter ?

2) Attach the adapter. Post the voltages from the attached locations. Meter in volts mode, black lead on ground. Red lead on each requested location.

3) Volts on L7095, pin 2 = PP3V42_G3H. This rail must be 3v42 or close to this value.

[sassan]

Re: macbook A1466 no green light

1) Is the adapter an Apple original? Is it a known good working adapter ?

2) Attach the adapter. Post the voltages from the attached locations. Meter in volts mode, black lead on ground. Red lead on each requested location.

3) Volts on L7095, pin 2 = PP3V42_G3H. This rail must be 3v42 or close to this value.

Location 1 = 8.57V
Location 2 = 15.09V
Location 3 = 14.83v
Location 4 = 3.427v

Thank you .

[mon2]

Re: macbook A1466 no green light

Is the missing green light on the magsafe power adapter head?

[sassan]

Re: macbook A1466 no green light

Is the missing green light on the magsafe power adapter head?

yes,it's missing.

Thank You.

[mon2]

Re: macbook A1466 no green light

1) Power down. Meter in resistance (ohms) mode. Black lead to ground. Red lead on (usually white in color) fuse F7140, pin # 2. Value in ohms ?

You may have a bad cap on the logic board that is causing a very low resistance (CPU rails are ok to be low in value). A high current draw occurs on the respective rail and the local power supply then shuts down to prevent damage.

Review each coil for each power rail on the logic board and post their resistance to ground. All with the power removed.

If the resistance for each coil to ground is ok - then a bad cap is not the issue so continue with...

2) Post your voltage for PP5V_S4RS3 rail @ L7520, pin # 1.

3) Confirm the voltage reaches the connector J7000, pin # 3.

4) The LEDs onboard the magsafe head are based on the Maxim (aka Dallas) Semiconductor 1-wire interface. Using a single wire / pogo contact pin, communication occurs between the magsafe adapter and the host logic board.

After a handshake occurs between these 2 parties, the magsafe power adapter will power up to the max voltage to power the logic board.

Check that the pogo pin contacts are clean on your paddle (LIO) board that mates with the magsafe adapter. This is very important. Recommend to use a cotton swap or similar with alcohol to clean up each contact.

Also attempt to power up the logic board without a battery. Does this allow for the magsafe light to turn on?

5) Check that the bridge cable between the main logic board and this LIO board is solid and with no corrosion. These cables are relatively low cost to replace (821-1722-A).

6) The LIO board may be defective. Not aware of any schematics for this paddle board.

See here:

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

The power cycling issue to me would indicate a power supply issue on the main logic board. The logic board does not remain powered up long enough for the host to communicate with the magsafe power adapter to enable the higher adapter voltage which also is the same 1-wire interface to change the LED colors.

[sassan]

Re: macbook A1466 no green light

Hello,

i cleaned the bridge cable between the main logic board and LIO board ,now i get the orange light on the megasafe with and without the batttery .trying to switch it on same thing,the fan spins then stops,no display no nothing.

Thank you.

[mon2]

Re: macbook A1466 no green light

Post the values from the earlier requests. Interested in each coil (grey inductors on logic board) resistance to ground with all power removed. A very low resistance will denote a bad or shorted caps which are quite common.

[sassan]

Re: macbook A1466 no green light

Post the values from the earlier requests. Interested in each coil (grey inductors on logic board) resistance to ground with all power removed. A very low resistance will denote a bad or shorted caps which are quite common.

OK,
here is what i did so far:

yesterday when i cleaned the bridge cable between the main logic board and LIO board ,the magsafe light is back on(orange),i plugged the battery left it until the battery is charged then became green.

when i press the power button the fan spins the immediatly stops (same thing on the battery alone).

L7310 L7320 23,4 ohms
L7630 192 ohmS
L7430 329 ohms

L7520, pin1= 0volts,

Thank you for your help.

[mon2]

Re: macbook A1466 no green light

L7520, pin1= 0volts

Resistance to ground on L7520, pin 1 ?

Voltage on R7551 = Enable for this rail via pin # 4, U7501 ?

voltage @ P5V_S4RS3_DRVH ?

voltage @ P5V_S4RS3_DRVL ?

voltage @ PPBUS_S5_HS_OTHER_ISNS ?