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Macbook Pro A1707 820-00281-A Dead after water damage

S

sourcensolutionsonline@gm

Member
That macbook came to me after water damage , Pulling 0.006 on DCPS and when connect to the USB AMP Meter only was showing 5.23v so i checked U3100 and U3200, so i have found resistor R3033 which a [UPC_XA_HPD_RX] and R3034,[UPC_XA_HPD_RX] and on both sides they measure 0.00v so I Thought that those were shorted and i removed and replaced them , as well as U3100 nd U3200 now i am getting on R3033 And R3034 0.750ohms , Now i am getting the 20v on my amp meter but macbook is acting very weird , as i plug usb cable with amp meter , fan would promptly start spinning then stop then restarting again , but no image on screen , Can someone explain me what [UPC_XA_HPD_RX] for and is it normal for their reading 0.00ohms.
 
2informaticos

2informaticos

Administrator
Staff member
First of all, welcome to the forum!

R3033/34 appear both as NO STUFF in schematic.
Did you really found them on the board?
If yes, what value did you place in their position.

Their pin 2 goes to ground, normal to get short to ground, don't you think?
Both are 100K, if were placed on the board.
I don't understand how can a resistor get shorted; unless it has low value as normal (not really short then).

Try to understand a schematic, or ask for help BEFORE changing things without reason.
Your power problem was U3100/200 related.

Does the board stay on after second restart?
Did you check for voltage on big coils?
USB activity present?
 
S

sourcensolutionsonline@gm

Member
Thank you very much for your prompt reply , Indeed You do have a point , and i did find that later that those were not supposed to be removed and replaced , but i was very confused since the reading on the amp meter was giving 5.23v was thinking maybe those resistors were probably the one causing the issue , but apparantly Yes U3100/200 was my problem .

The board seems to stay on , cause i made a test with the battery connected and when i plug the usb cable i can hear the sound that the power cable is connected but no image , no backlight on either screen nor keyboard.

when i test the big coils i am getting 0.00V
 
2informaticos

2informaticos

Administrator
Staff member
I talk about REAL USB activity, not power.
Get an USB pendrive with preinstalled macOS and Link LED; if flashes, there is 100% activity.

0V on all big coils???
Then no reason to search for image, nor USB activity.
But if fan spins, 5V is there at least.
And you heard even power sound!
I bet you have voltage on more coils...
 
S

sourcensolutionsonline@gm

Member
I Don't have a pendrive handy , I will Recheck all the coils again , now my how do i get R3033/3034 To their original state since i am getting 0.765 ohms since they were supposed to be 0.00 ohm that was what I was getting initially when i started diagnosing the macbook. Also do you have some specific coils do i have to check or I have to check all of them?
 
2informaticos

2informaticos

Administrator
Staff member
As I mentioned before, R3033/34 have 100K both; check schematic, please!!!
You've get 0 ohms before because of bad U3100/200.

How do you get power sound when connect charger, if no voltage on coils?
Nothing on L7600?
What about 3V3_SUS at least?
 
S

sourcensolutionsonline@gm

Member
Hi , L7600 I was getting also 0V, I did not check 3v3_SUS , I will check that too and get back to you . In Regards of R3033/34 , I did not have a donor board to measure their resistance to compare , but funny thing about it , I changed U3100/200 First then check Resistance of R3033/34 And was still 0V that was how i got confused , but with that, i was getting fan spinning then stopped but like i mentioned if battery is connected when connecting USB cable and connect it back that was when i was getting sound , But no display , no back light on keyboard or screen , that was when i changed R3033/34 and since then i am getting fan spin but very prompt and stop then restart again but this time with battery connected if i connect the cable , i am not getting the sound anymore. do you have any chance have a good working board if you would please give me the resistance value of R/3033/34 I know one side goes to ground but the positive sides.

Please
 
S

sourcensolutionsonline@gm

Member
2informaticos said:
I already said you two times; these are 100 Kohms resistors, exactly as in schematic.
Click to expand...



2informaticos said:
I already said you two times; these are 100 Kohms resistors, exactly as in schematic.
Click to expand...


Hello

You were helping me last week with this macbook pro A1707 , I was able to figure out the issues and it got it fixed , but now there s a funny thing that i am getting and i am not able to figure it out , before i point anything out I decided to first reach out to you for help.

Now all power rails are responding ok , but i am getting this weird backlight issue which is very funny to me , when powering the device ,it turns on normal but then as soon as the keyboard lights up the lcd promptly shows apple logo booting for about 2 seconds then goes black , then promptly flashes back again then backlight goes off again , i cleaned the LCD fpc connector , it turned on normal so as soon as i disconnect the lcd connector and reconnect it i am getting the same , but keyboard backlight is working perfectly fine , now the other thing that i found funnier is if i disconnect the battery and connect the USB charger keyboard backlight does not turn on, but LCD showing normal backlight with battery sign only . So I am assuming that my backlight driver IC is working , so can this issue relate to the battery or the flex that connect the lcd to the motherboard , i do not have another flex cable here to make a test. Please advice

Thank you.
 
2informaticos

2informaticos

Administrator
Staff member
Do you note any change if rotate the screen?
Test that, against classic flexgate issue.

Please, do NOT quote again on this manner...
 
S

sourcensolutionsonline@gm

Member
I apopologyse , I chose Reply that was why it came up that way , When i rotate it remains the same I can see image on the screen when shining with a bright light but no backlight, but as soon as i disconnect the battery and connect the charging cable then I see normal back light and no light on keyboard but simply show the battery charging sign , let me know if i can upload a short video to show you the funny behaviour.
 
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