No 5v

[RESQ-MYTECH]

Hi all, greetings from the UK... again. Now i am a little lost with this... nothing unusual.
MBP A1297 820-2914-A. Red bull definatly did not give it wiings. Keyboard naffed. Green LED on magsafe. No power. Motherboard surprisingly clean and dry. no corrosion visible across the board even under the scope. The was sticky residue on pins 1-4 of the LVDS connector, cleaned with flux and touched up with new solder. Still no power. Removed the board and started testing the power rails.... this is what I have so far:-
PPBUS_G3H 12.57V
PPVIN_S5_HS_COMPUTER_ISNS 12.57V
PPVIN_S5_H3_OTHER_ISNS 12.57V
PPDCIN_G3H 17.04V
PP3V42_G3H 3.48V
PPVRTC_G3H 3.323V
PP5V_S5 UNABLE TO LOCATE ON THE "NET" COMMAND
PP5V_S3 0.0V
PP5V_S3_ISNS_R 0.0V
PP5V-S0 0.0V
and following down the list of power rails becomes obvious the board is devoid of 5v

Now looking at the board view there is listed components in the location UD300 where going by the schematic I have should be 5v points. there is not a single component there. Not unduly worried as there is o solder there either.

Maybe I have gone letter blind but I can seem to find on the schematic the first instance of where 5v feed should be. I have gone away, had a cup of tea, come back and still unable to located where 5v first emerges. Would anyone be king enough to point me to where or what produces the 5v

 

[2informaticos]

5V_S5 comes out from pin29/U7201 (VREG5).
3V3_S5 comes out from L7260.
Both require SMC_PM_G2_EN presence.
If none present, chek if pulse at least.

 

[JohnB8812]

Expect a dead GPU after fixing this one just as a heads up...

 

[RESQ-MYTECH]

2informaticos got these readings:-
PP5V_S5 = 5.043V
L7260 = 3.323V
SMC_PM_G2_EN = 3.476V (STEADY)

JohnB8812 I had a feeling this may be the case but was not sure. After a bit of searching this would seem to be the consensus as to the most common cause of failure.

In both of your opinions is it worth pursuing this? Prices for these boards are commanding £400+ over here.

 

[2informaticos]

You can check at least basic things.
If turns on, can see if GPU has problems...
Check voltage at L7560, or pulse at least.
Be sure to use original Apple 85W charger; it will not turn on with 60W.

 

[RESQ-MYTECH]

2informaticos see, this is why you get the big bucks for the big jobs.... you hit the nail on the head with the adapter. customer gave me a 60w and swears blind this is what they have been using, used a 85w adapter and powers on. get the chime and an apple logo on the screen but no illumination. with the original screen, I can see lines as though the GPU is failing. Tried a known good screen and although no illumination, shining a torch through the apple logo on the lid there are no green lines. This would indicate either a screen or cable issue.However, I wanted to make sure so I want to get the screen to light up. So again, I have attempted to troubleshoot... and I know I am going to be told I am wrong but here goes.
J9000 pins 2&3 no voltage. Traced back through C9002->L9000->C9001->C9012->C9011 to pins 4&5 on U9000= no voltage. Checked pins 2&3= 3.322v. Pin 1= no voltage. Followed LCD_PWR_EN to R9678= no voltage. Q9607 pins 1&4 GND pin 2= 3.317v pin 3= 2.653v pin 5= no voltage pin 6= no voltage. U9600 is getting warm but can comfortably leave my finger there without getting burnt ( technical scientific testing there, doesn't burn= not hot...LOL). Other end of J9000 pins 38/39/40= no voltage. at C9008 there is no voltage. Tracing PPVOUT_S0_LCDBKLT at D9701 pin 2/ XWD150 pin 1/ R9708 pin 1/ C9717 pin 1/ C9716 pin 1/ C9718 pin 1 all have no voltage. D9701 pin 1= no voltage. C9712/13 also have no voltage at pins 1. there is no voltage at L9710. I have looked on boardview and can not locate R9700 but there is a XW9700 which is local to Q9806. XW9700 is not on the board. Pins 1/2/5/6 of Q9806 have no voltage. Pin 4 which goes via a fuse to PPBUS_G3H is reading 0.800v the same as on pin 2 of F9800 and pin 1 is 12.57v. Replaced the fuse and instantly popped.

So in essence, replacement screen and/ or cable required. Keyboard required. Further I go into the board, the more issues I find. Cost of replacement logic board is £400, replacement lid is £250 and keyboard is £15 without labour costs. Replacement A1297 same spec is £550. Even if I buy the replacement and just swap his HDD and charge £50 labour it's going to work out more benificial, especially as there may be further issues along the line. Plus I have told him he will have a spare HDD, RAM and a battery. I think this is the way he will go.

I hate it when something gets the better of me, and I am sure someone better versed at repairing the logic boards will be able to repair quicker, so far I have spent in excess of 4 hrs and still no further.
2informaticos as I have said to you many times before, thanks for your assistance and it is greatly appreciated.