A1286 820 2850 no hdd detected

[marce002]

Hi

I have this macbook pro from 2010... board 820 2850 . powers on ok .. boot from usb , but no way to detect HDD ... flex is ok and connector has required voltages... are present...
also no water or liquid damage... can this be a pch damage? or maybe can you please suggest me to look for any other area?

[mcplslg123]

Re: A1286 820 2850 no hdd detected

Replace the HDD cable as it fails often on this board. The cable never looks damaged but replacing the cable solves the HDD detection issue. I've faced this 3-4 times in last 2 years and every time it was hdd cable faulty.

[marce002]

Re: A1286 820 2850 no hdd detected

No thanks but not that issue., have already done.. the cable is fine as stated in my first post... it would be a shame for me to post without that having tested that, and resulting the culprit... it seems to be a rare case of bad pch since the ODD also not working and traces dual coils caps are fine and no water damage, any other hint?

[mon2]

Re: A1286 820 2850 no hdd detected

Further to the comments raised by @mcplslg123, do confirm that the cable is working in another box. The reason being that we ordered a batch of these cables from a reliable supplier on Aliexpress. Upon arrival, serviced the unit and off it went to the customer. A few weeks later, customer returned with the same fault. Once again, we replaced the cable and she left the building. The cycle repeated and the next time she came here (not a social visit), we watched the tech like a hawk. While shooting the breeze, he kept creasing the cable like a madman. After screaming with 'what are you doing?' - he replied, it is for a better fit. Nasty child, you are killing the cable in the process! Needless to say, this final time for the repair, the cable was gently seated into place with no extra cable massaging - fixed for good this time.

The flex cables are like rigid PCBs - be 1000% sure the cable is solid (no pun) by testing in another box. Otherwise, it is still a suspect. Just sayin..

[marce002]

Re: A1286 820 2850 no hdd detected

yes the cable works fine in another box... tried also a working original cable from another a1286 2010 and does not work here and reinstalled in source donor mac and it works just fine.

[mon2]

Re: A1286 820 2850 no hdd detected

Is U4510 present on your logic board ? If yes, confirm the power rails (VDD) and connections for this component.

It is a SATA signal redriver IC that basically cleans up and amplifies the high speed data signals to / from the SATA drive to the PCH path.

Confirm that none of the caps and coils / inductors between the PCH / SATA HDD are defective / missing / broken.

[marce002]

Re: A1286 820 2850 no hdd detected

yes u4510 is clean and present... al tracks caps and dual coils are ok, and 5V is exact 5.00V !!! , the problem is that in this unit Optical drive does not work either...so pch? ... i have an exact 8250 board as spare just in case, but not able to replace pch, cannot do this chip with my equipment.

[marce002]

Re: A1286 820 2850 no hdd detected

odd connector does not use u4510, it seems to go directly to pch through some caps, so i thing this is going to be hard to solve, or maybe im missing something else... remember does not work even attaching a ssd to the ODD connector via a carry case for sata drives.

[mon2]

Re: A1286 820 2850 no hdd detected

Can you confirm that you have tested the ODD drive using the dedicated ODD connector it also failed ?

U2700 is a critical component to the operation of the SATA function - it offers the clock source for this function.

Check PCH_CLK100M_SATA_N and PCH_CLK100M_SATA_P.

[marce002]

Re: A1286 820 2850 no hdd detected

Mon yes confirm i have tested ODD with original and ok connecctor and flex . i will check what you said regarding U2700 that I did not check before as though it would be unrelated. Area seems to be clean to so hope will find something else... in the meantime remember the macbook works just fine booting linux (FROM USB) and shows a blinking folder when nothing is attached, as expected.... i will keep in contact after testing u2700 zone , thanks

[marce002]

Re: A1286 820 2850 no hdd detected

Update

RES to GND

This board

PCH_CLK100M_SATA_N to gnd: 2.138 Mohm
PCH_CLK100M_SATA_P to gnd: 1.97Mohm

Another 2850 board:

PCH_CLK100M_SATA_N to gnd: 1.553Mohm
PCH_CLK100M_SATA_P to gnd: 1.576Mohm

[mon2]

Re: A1286 820 2850 no hdd detected

Is the drive formatted to be used with the macbook or is it a new drive?

Just an article noting the same:

https://www.ifixit.com/Answers/View/...nal+hard+drive

[marce002]

Re: A1286 820 2850 no hdd detected

Hi, yes the drive is formatted to be used with the macbook, because was tested working in another identical macbook, booting high sierra.

Im worried about RES to GND from this board, because as stated in post #11 is abnormal. should it be bad PCH? even if the mac boots linux from usb?

[dellxps15]

Re: A1286 820 2850 no hdd detected

edit hdd spin ?

voltage on R45901 U4510 and power on macbook then power off (with psu attached) and see if hdd still spinning or stop spinning

check also XW4598

[marce002]

Re: A1286 820 2850 no hdd detected

thanks to all it happened that was using an ssd when i tried an hdd it was recognized finally... seems to be that 2010 does not boot from a ssd with macos preinstalled from another mac, thanks and sorry