MacBook Air A1465 820-3435-B chimes but no video

[carlucci]

Hi.
I have a MacBook Air A1465 820-3435-B that gives chimes but doesn't give an image on the screen, i've already tested the backlight and it's ok, any suggestion will be welcome. Thanks.

regards,

Carlos

[mon2]

Re: MacBook Air A1465 820-3435-B chimes but no video

Check and post the following:

1) voltage readings for I2C_TCON_SDA_R, I2C_TCON_SCL_R.

2) voltage readings for PP3V3_S0SW_LCD, PP3V3_S0SW_LCD_UF.

3) confirm the caps for the lcd interface are present (see attached).

4) is the display a known good LCD ?

[carlucci]

Re: MacBook Air A1465 820-3435-B chimes but no video

Hi,

This are the readings.

I2C_TCON_SDA_R - 0.14v
I2C_TCON_SCL_R - 0.13v
PP3V3_S0SW_LCD - 0.51v
PP3V3_S0SW_LCD_UF - 0.18v

[mon2]

Re: MacBook Air A1465 820-3435-B chimes but no video

These are not good readings.

Is the lcd display connected?

If yes, remove it and check and post the voltage readings again.

[carlucci]

Re: MacBook Air A1465 820-3435-B chimes but no video

No it's not connected. I remove the board from the case.

[mon2]

Re: MacBook Air A1465 820-3435-B chimes but no video

Voltage readings for:

1) EDP_PANEL_PWR ?

2) PP3V3_S5 ?

[carlucci]

Re: MacBook Air A1465 820-3435-B chimes but no video

Voltage readings for:

1) EDP_PANEL_PWR ?

2) PP3V3_S5 ?

EDP_PANEL_PWR ? 0.6v

PP3V3_S5 ? 3.30v

[mon2]

Re: MacBook Air A1465 820-3435-B chimes but no video

EDP_PANEL_PWR is the wrong voltage to enable the power rail for the LCD panel.

Remove all power (no battery / no adapter).

Meter in resistance mode.

Check the resistance to ground for EDP_PANEL_PWR. If the resistance is too low then it is shorting to ground. If the resistance is ok then this pin is not being driven to the proper logic level to turn on the load switch @ U8300.

Post the resistance.

[reformatt]

Re: MacBook Air A1465 820-3435-B chimes but no video

Check for corrosion under U8005 (1.05V PCH HSIO switch). I had the exact same problem today on a 820-3437 board. It's right at the edge so easy for corrosion to get under that. Such a small IC that it's quite easy to miss.

[Lightcap]

Re: MacBook Air A1465 820-3435-B chimes but no video

I cannot seem to start a new thread so i'll add this one please;

MacBook Air A1465

I have to above laptop, the backlight is on but on image, the start up chime is there and the fan spins.

Also when then battery is dead the battery icon appears on the screen so i guess the image in there then.

I have also tried another screen which does the same.

I'd be greatful of any pointers of what to check next?

Thank you

[mon2]

Re: MacBook Air A1465 820-3435-B chimes but no video

try a PRAM reset.

[Lightcap]

Re: MacBook Air A1465 820-3435-B chimes but no video

try a PRAM reset.

Just tried that but it still the same, thanks.

[mon2]

Re: MacBook Air A1465 820-3435-B chimes but no video

What is the history of your unit ?

Liquid damage ? It just stopped working ?

See attached. Review the highlighted parts.

Any sign of corrosion ? Share pics of the LCD connector on the logic board.

Given that you have tested another known good LCD panel, the issue is with the logic board and not the LCD panel (assuming the 2nd tested LCD panel is working).

[Lightcap]

Re: MacBook Air A1465 820-3435-B chimes but no video

What is the history of your unit ?

Liquid damage ? It just stopped working ?

See attached. Review the highlighted parts.

Any sign of corrosion ? Share pics of the LCD connector on the logic board.

Given that you have tested another known good LCD panel, the issue is with the logic board and not the LCD panel (assuming the 2nd tested LCD panel is working).

Thanks.

As i read your previous answers before i posted, i have checked both the caps, none are short and i have 3v3 on that pin.

Is there a resistance map of the lcd connector?

I should add that i mostly do board repairs on iphones, for the past 10 years but very little on macs.

[reformatt]

Re: MacBook Air A1465 820-3435-B chimes but no video

You mention that you see a battery icon when battery is low and you get a chime. So display is ok, it's POST'ing, so seems to be a boot issue. If there is no bootable OS, you will get a flashing folder icon on the screen but you need to wait some time for that to appear.

Hold the OPTION key on boot up, do you get to the bootpicker menu? Also try recovery mode CMD + R to see if it will get into that.

[Lightcap]

Re: MacBook Air A1465 820-3435-B chimes but no video

HI,

Both the option key on start and the CMD + R on start make no change, thanks.

I'll leave it on and see the the folder icon appears.

[mon2]

Re: MacBook Air A1465 820-3435-B chimes but no video

Remove all power. Remove the SSD and power up again.

Do you see the flashing folder icon everytime ?

If yes, the video works and your LCD is fine. Confirm this first.

[Lightcap]

Re: MacBook Air A1465 820-3435-B chimes but no video

Remove all power. Remove the SSD and power up again.

Do you see the flashing folder icon everytime ?

If yes, the video works and your LCD is fine. Confirm this first.

Thank you for your help, removed ssd, flashing folder with ? is on screen now.

SSD knackered?

[mon2]

Re: MacBook Air A1465 820-3435-B chimes but no video

Appears to be. Not with much experience on this but recall our techs using an external clamshell (USB housing from OWC) to host this SSD and then erasing / applying new OS onto the drive.

They are cheap on the open market - not a bad idea to test with a known good SSD for this model.

Do update this thread once you have had a chance to test another SSD. In the meantime, check for any possible contact fluff on the PCB for this SSD socket. Clean with IPA - always a good idea.

[Lightcap]

Re: MacBook Air A1465 820-3435-B chimes but no video

I'll try another SSD and follow up here, many thanks!