Macbook Air 820-00165 Static Chime Sound

[Comp_Pro]

Hello all,

I have a weird issue to solve here. This macbook air came in showing a black screen even though the backlight was lit. The display was not the issue as I tried another known good display. Upon trying to restart it, sometimes it boots up but freezes at the login page. More commonly however, the macbook will give the chime sound but then get stuck repeating the sound. The first chime sound is normal but the subsequent chimes sounds are crackly. Voltages seem normal, no liquid damage. I did find a blotch of something near one of the crystals on the other side of the CPU but nothing really serious, cleaned it up with no difference.

Seems like a somewhat common issue but can't seem to find any actual solutions. Here are some forum posts mentioning this exact issue.

https://discussions.apple.com/thread/251456995

https://discussions.apple.com/thread/252699237

One of the posts suggests that the hard drive is full and that this is the issue but I don't think so as mine does it even with the hard drive removed.

[reformatt]

Re: Macbook Air 820-00165 Static Chime Sound

Can't say I've come across this fault before. Does this happen on magsafe or battery only? Make sure you do tests with a genuine Magsafe 2 charger too as some 165 boards are very picky about them. BATLOW prevents them going to PM_SLP_S4 usually in that case.

I'd be casting an eye at the keyboard facing side at base of the board (U1900, U6100, U1930 etc). This tends to be where most of the dust/corrosion occurs and can be very subtle. Look for passive components which have corroded end caps, as they usually have damaged pads underneath.