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820-3435 faults

J

jpadie

New member
Hi

The 820-3435 I've been repairing is mainly done now. Powers on ok, screen connector and cable replaced as well as bunch of passives and the clock chip .

Two things are still awry .

1. The camera is not present .
2. The right arrow key of the keyboard is not recognised .


Any thoughts on these? How repairable are individual parts of the kB matrix? I've not pulled one apart but I find it odd that one key is bust as opposed to a section.

And the camera? Connector is ok. Any thoughts on where to look for errors? I guess this need to be debugged whilst turned on with photo booth loaded, or equivalent.

Thanks Justin
 
D

dukefawks

Administrator
If it is only 1 key then it is just a bad keyboard.
Camera is a problem :( I assume you already inspected the connector and tried a known good camera in another LCD?
 
J

jpadie

New member
That's disappointing about the camera . I have not tried a known good camera - I have no spare sensors but will buy some. There was no trauma to the screen however . Just liquid spill on the keyboard.

Although it did heat up the hinge cover sufficiently to burn a hole in it. The camera cable looks ok nonetheless .

No point in a new kb when the camera isn't working though. The client uses the machine for Skype coaching and doesn't want to go down the usb usb camera route .
 
D

dukefawks

Administrator
Try a cracked LCD assembly, 11 an 13" are same connector. But usually this will end up with a U3900 replacement and trust me that sucks. Do a diode mode measurement on the camera connector too.
 
J

jpadie

New member
I've ordered a new kB, camera cable and camera. 40€ so not too terrible and useful even if not used on this board .

Gave thet laptop back to client whilst the parts get here . She tried an SMC reset in case that was behind the camera issues (no good reason, just a ''cant hurt to try"). Logic board won't power up now.

Any known reason for that?
 
S

SMMRepair

Member
Keep in mind as well: If you clean the ME region on a 3435/3437, it will kill the iSight. I'm not sure what all you replaced on the unit, but if it had liquid to the clock, I might assume you had to replace or resolve the BIOS. If you did, then camera is fucked because it needs original ME info.
 
J

jpadie

New member
Not replaced the bios. Just the clock chip and the smc_reset_l chip

What do you mean by the ME area?
 
J

jpadie

New member
Also if there is an association between the camera and the bios does that mean the camera cannot be swapped?
 
J

jpadie

New member
For posterity I ought to add that in addition to the right arrow key the power button also failed on the kB .

​​​​​​But interestingly the device still managed to get through an SMC reset. Wonder how it did that without the power button.
 
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dukefawks

Administrator
Camera can be swapped. Cleaning the ME would also not kill the camera if you did it right. If you do it the "ghostly hacks" way then yes there will be all sorts of random problems!

How would you be able to power it on without the power button working?
 
J

jpadie

New member
Wouldn't plugging it in power it on?

​​​​​​I'm getting the machine back in a couple of days to swap out the keyboard. Customer reports that the charger led no longer turns orange too. But I don't see how an SMC reset can cause that when it was working fine before. So I'm not factoring that it yet.
 
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dukefawks

Administrator
If you have a working battery connected it will not power on when plugged in anymore. No green light is probably bad IO board and/or flat cable.
 
P

phuketmymac

New member
Hi guys,

Can you explain why cleaning the ME region would "kill" the camera please? Which guide can we follow to avoid disabling the camera when replacing the ME region?
I have a 820-3437 board also with a not detected camera. Diode mode measures fine on the connector and on U2030 so I was assuming it would be U3900 but since you are talking about the ME region too...

Thanks
 
S

SMMRepair

Member
I know duke mentioned cleaning the ME properly would not kill the camera/isight, and he is MUCH more knowledgeable than I am, but I have cleaned the ME on dozens of 3435/3437 boards and a large percentage of the time, iSight appears to no longer work ("no camera detected") after the cleaning. However, if you then update the BIOS via HS update or bless/mount, it does often restore iSight functionality (~75% of the time). When I say "clean the ME", I mean copy/paste a "clean" (default) ME region from the downloaded Intel ME region file (for the appropriate BIOS version) and pasting it over the corrupted/bad/old ME region. The only time I do this is when I am loading a totally fresh BIOS to a board for whatever reason--i.e. PCH replaced, damaged chip, missing chips altogether, etc. Any situation where a clean ME is needed. For reference--I do not use ANY ghostlyhaks files, ever. I use all my own files, pulled from my own fully-working boards and cleaned by me. To test this, I have pulled the BIOS from a fully-working board (with no problems, fully-working iSight, etc)--tested both a 3435 and 3437--and ONLY "cleaned" the ME region using the above method. Once I loaded the cleaned file, iSight no longer worked. I replaced the original file and iSight worked fine again. I also tested updating the BIOS, and it seemed to help sometimes, but not always. Again, this is with previously fully-working boards (including iSight). This DOES NOT seem to affect boards other than the 3435/3437 for whatever reason. I haven't messed with it enough to speak beyond this.

I have noticed that manually updating the BIOS via bless/mount, or performing it with El Cap/HS update, has around a 75% chance of fixing iSight, but I have seen it NOT restore iSight as well. I don't know enough about ME regions to know *exactly* what breaks, but as duke has referenced before, the ME region pulled from the intel file is simply a DEFAULT SETTINGS ME region. I imagine whatever settings pertaining to iSight are incorrect/different and thus result in a non-functioning camera. I haven't had to clean the ME on a 3435/3437 board in months (market is softening for them), but last time I did, I had iSight issues as well. The way I do it is: Pull BIOS dump from working board (I have a library of ~15-20 good, working dumps per board model at this point that I have saved--all from fully-working boards that were not updated to El Cap); clean ME by pasting intel file default ME over KRID block with proper length; edit serial to match destination board; write to chip; PRAM reset on first boot; proceed to force-update (bless mount) to newest EFI version to have ME region corrected to perfectly match board/PCH. Works perfectly for most boards, but the 3435/3437 boards still seem to have iSight issues sometimes regardless.

Duke, would you mind briefly noting what the proper way of cleaning an ME region is? I could definitely be doing it incorrectly, and don't want to spread misinformation. Since ME regions are board-specific, it would seem the only way to clean them is to reset to default settings (via the intel file) and then PRAM reset on first boot, right?
 
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phuketmymac

New member
Thanks SMMRepair! Glad you did answer that precisely.
Looking forward to hearing from Duke too.

Regarding your manual method, if I want to make sure to flash a bios version which is going to need an update...
Can I simply get the Bios file from the MacBook Air EFI Firmware Update 2.7 and apply my SN, flash it to the chip, then use Mavericks or El_Capitan to apply the MacBook Air EFI Firmware Update 2.8? (in case of a 2013 MBA 13")

MacBook Air EFI Firmware Update 2.7: https://support.apple.com/kb/DL1689?viewlocale=en_US&locale=en_US
MacBook Air EFI Firmware Update 2.8: https://support.apple.com/kb/DL1749?viewlocale=en_US&locale=en_US
 
D

dukefawks

Administrator
You can just ask on the forum for your BIOS to be fixed, then it will always have a known good ME. Just sticking in a clean ME without at least transferring over all the settings from the original will cause issues like this.
 
D

dukefawks

Administrator
Yes it is possible, just ask with board number and original serial number. But it is always best if you have the original BIOS to work with.
 
P

phuketmymac

New member
Then please, 820-3437 board 1.3GHz 4GB. Seriously corroded board on the top edge (I can provide picture) where I had to replace a few chips like the clock chip, the Bios chip and some alongside the edge.
For Serial number, can I provide it by PM? (don't want to leave it on the forum board)
 
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