820-3476 keyboard/trackpad cuts in and out

[arghhh]

I have got two 820-3476 where the keyboard and trackpad randomly starts and stops working. Pretty sure they are not recognized as USB devices when this happens. Keyboard controller?

 

[dukefawks]

Nah, Inspect for corrosion on flatcable/connector to trackpad first.

 

[arghhh]

Looks good, testing with known good cable.

 

[dukefawks]

Connect a known good trackpad+cable to the board. This boards will freak out if there is no trackpad connected and the KB and TP will go on/off. Pretty sure this will be a bad TP or cable/corrosion.

 

[arghhh]

Yea, I have definitely tested this in two good whole top cases. What if they aren't being detected as USB devices in system info? Because that may be a possibility for one of them.

 

[dukefawks]

That is what they do if the trackpad is not working properly. USB cuts in and out. Inspect for liquid damage and corrosion again.

 

[arghhh]

I left this alone until now, and it seems to have gotten worse while sitting. It works fine when the IO board flex cable is unplugged. Once I plugged the IO board in, it does the following:

• I can hold the option key to get to the boot menu, however once I get to the boot menu the internal keyboard/trackpad stop responding (caps lock key does not even light up). A USB keyboard works fine.
• It will hang at the Apple logo when it tries to boot. No loading bar or anything.

PCH??

 

[dukefawks]

Have you tried a good IO board and cable?

 

[arghhh]

Yes 10 char

 

[dukefawks]

Also another or without the airport card?

 

[arghhh]

Without the airport card it works fine.

 

[dukefawks]

Bad card? ..

 

[arghhh]

No it works in another system and a second card causes the same thing.

 

[dukefawks]

Does airport and BT work when in OSX?

 

[arghhh]

Not sure how to test that. Should I boot it up and then just pop the airport card in while it's on? I thought airport is PCIe.

 

[dukefawks]

Uhm, what is preventing boot up with the APX installed?

 

[arghhh]

This:

I left this alone until now, and it seems to have gotten worse while sitting. It works fine when the IO board flex cable is unplugged. Once I plugged the IO board in, it does the following:

• I can hold the option key to get to the boot menu, however once I get to the boot menu the internal keyboard/trackpad stop responding (caps lock key does not even light up). A USB keyboard works fine.
• It will hang at the Apple logo when it tries to boot. No loading bar or anything.

PCH??

10 char

 

[dukefawks]

Oh yeah. Hmm, you can disable BT by removing U3510 and disable APX by removing L9501. See if it is BT or APX causing the issue.

You saud you have 2 boards, both the exact same issue?

 

[arghhh]

No, I sent one of them back no fix but I can't remember which one unfortunately, sorry.