820-3330 Killing SATA Cables?

[SMMRepair]

I can't edit the title, but I got this board mixed up with another one (very similar). This is also an 820-3330 board.

Symptoms:

1. Board won't detect hard drive; doesn't show in EFI, and flashing folder appears.
2. Drive gets power; I can hear the whine of the drive being powered, but no "ticking" (data). When I disconnect power, I can hear the typical click-off of drive.
3. Pin 7 of U4510 is 3.3v
4. C4510 and C4511 both look like they've seen significant heat/draw (not shorted, but darker-yellow on the end caps than others)
5. Board boots to USB drive fine; WiFi, BT, Audio, etc., all work.
6. Drive not detected in disk utility or System Info, of course.
7. All resistors measure out fine around U4800/U4510, etc.

So I suspect some issue with the data connection. I replaced U4510, C4510 and C4511, but no dice. There are lots of data lines related to J4501, so unsure which others I should be looking at.

 

[dukefawks]

3115 I assume. Did you try a known good HDD cable? Don't fold them too sharply as they will be dead again.

 

[SMMRepair]

Hey Duke. This is still an 820-3330, apologies for confusion. Tried tons of known-good cables, no dice. Also tried 3 other boards in the same casing and all work well/fine.

Could it be a PCH issue? No liquid, but maybe a drop? I've seen a few dropped boards that had very particular/singular issues like this...most commonly, missing data/clock signals to LCD.

 

[dukefawks]

Checked C4510,11,15,16? Checked continuity from HDD connector SATA lines to those caps? Only 4 data lines involved in this.

 

[SMMRepair]

Hey Duke, thanks. I just re-checked all those things; continuity between all caps & J4501; continuity from U4510 to C4517/18. All checks out.

I checked at C4517/18 pins 1 with an oscilloscope, and on a good board, it's a nice healthy signal. On this bad board, nothing (drive connected, etc). I might give up on this one, thinking maybe a PCH issue. If you have anything else I should check I will. Thanks so much for the help! This one kicked my ass.

 

[Inwerp]

bit this is A1286, the only one laptop in entire history which kills SATA cables.

the exact reason is that when you install HDD it pushes flex cable hard enough to get a short to ground. since fuses never really blow in MacBooks, cable dies.
simply put some insulator tape under the cable in HDD cage and install a new cable. However, maybe it was one of the rare moments some fuse was actually blown by a short circuit.

 

[SMMRepair]

Thanks for the reply, but that's not the case here. This is certainly a board issue, thanks. We've replaced hundreds of cables due to the known-issue with them. This is definitely not a cable issue.

 

[dukefawks]

If it is a PCH issue chances are good that the DVD is also not recognized, did you check that? If DVD works just put a HDD caddy there and boot from there.

 

[SMMRepair]

Damn, good idea. Thanks, Duke. I'll check that today--interesting.