-
For $29/mo, we provide access to advanced level technicians who will answer your questions on any Macbook board related matter to the best of their knowledge promptly & walk you through how to solve your problem so you can deliver a working board to your customer.Subscribe Now
820-2838 won`t power up
- Thread starter Glenn
- Start date
The reason duke asked you to remove R7252 is because this is what sits between the enable signal and U7201. If U7201 is fucked and shorting to ground, it will pull that enable signal to ground as well. We are pulling off R7252 as a way to isolate where the issue is.
We have one of two issues.
1) P3V3S5_EN is being CREATED, but shorted to ground by defective U7201(replace U7201 as solution)
2) P3V3S5_EN is not being created at all(investigate why P3V3S5_EN is missing as solution)
Measure P3V3S5_EN without R7252 here.
You should follow the advice, but also ask in your head, why is duke asking me to do this? If you do this you will catch up with our reasoning and troubleshooting methods far faster than if you just follow what we say! Nothing will "happen" when R7252 is removed because R7252 being removed removes the path between the 3.3v rail enable signal and the chip responsible for 3.3v creation. This advice is not intended as a fix, but rather, as a troubleshooting tactic.
We have one of two issues.
1) P3V3S5_EN is being CREATED, but shorted to ground by defective U7201(replace U7201 as solution)
2) P3V3S5_EN is not being created at all(investigate why P3V3S5_EN is missing as solution)
Measure P3V3S5_EN without R7252 here.
You should follow the advice, but also ask in your head, why is duke asking me to do this? If you do this you will catch up with our reasoning and troubleshooting methods far faster than if you just follow what we say! Nothing will "happen" when R7252 is removed because R7252 being removed removes the path between the 3.3v rail enable signal and the chip responsible for 3.3v creation. This advice is not intended as a fix, but rather, as a troubleshooting tactic.
Glenn
New member
Sorry was was little too fast to answer. On p3v3s5_en i get 3.4V now. So then i have to replace the u7201?
Could i buy this on ebay?
Thaks for your comment louis im tray to ask what my shelf whay people whant me to too tings and tray to figure it out on the pdf file but all that is new for me have never seen a schematic befor in my life
Glenn
New member
is it this one i need to replace R7252 http://no.farnell.com/kemet/t520b157m006ate045/tantalum-capacitor-150uf6-3v-0/dp/2125175
and can i use this one to replace u7201 http://www.ebay.com/itm/2x-Texas-Ins...YAAOSwT5tWJ2Nz
Thanks
and can i use this one to replace u7201 http://www.ebay.com/itm/2x-Texas-Ins...YAAOSwT5tWJ2Nz
Thanks
Last edited:
Glenn
New member
I think that I have destroyed the entire motherboard .. removed u 7201 again last night and now I have many a points on u7201 giving me O L. nothing get hot and nothing starts up now. possible has a possibility I can not even fathom U7201.. mabye i heat the U7201 to mutch?
Last edited: