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[SOLVED]820-4924 No S4

Tony Tone

Tony Tone

Member
I read some previous posts and tried to help myself before I posted my question and already checked the R1300's. I've gone over some of these things so many times I am getting to have them memorized : ) But here is what I have:
R1300 (3.3) on both
R1301-1 (3.3) R1301-2 (3.0)
R1302-1 (3.3) R1302-2 (3.2)
R1303-1 (3.3) on both

C1020 Red to ground diode mode = 0.008
C1020 Black to ground Ohm = 16.7

So short on ppvcc_s0_cpu?
 
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Tony Tone

Tony Tone

Member
>>> Louis ! - Do you have a video on measurements in resistance to ground in Ohms? If so, which video do you discuss this? I don't recall seeing one.
 
D

dukefawks

Administrator
16.7 is fine on that bus. Some people have reported that these boards do not start without a good battery connected. I have not really run into that, but it could be a possible issue here.
 
Tony Tone

Tony Tone

Member
Duke, thank you !
You can close this bad boy out !
This took so long the customer gave up hope, so I bought it off them so I can fix it. I don't even want it, I hate Apple. I just wanted to fix it : )
I want to know more about the last part of diagnosing (the 16.7 Ohm) whats this called or what were we checking for so I can find out more about it?
 
Tony Tone

Tony Tone

Member
No. The battery was actually good. This board came in a long time ago with minor water damage so I can't recall all that I did, very little though. The U1845 I broke everyone I had off of donor boards. When the U1845 came in the mail I put it on and couldn't figure anything out. (I will make a mental note about the battery being attached for testing!). When I first plugged the battery in I got the battery charging symbol bright and clear. I waited awhile and tried to turn on but kept saying charging. Then I though the fan has to be connected, so I disconnected the battery and put the fan on and it started right up. I only let it stay on for a few seconds into the Apple logo.

Once I put it together and turned it on again it was dim, I was able to see the login part dimmly. So I thought it was backlight. But now I get no image -hahahaha !!!

I'm kinda glad because now I'll get to explore the image circuitry because I could never figure those out on my previous run-ins with no image. Backlight I've solved a few, but they were easy.

I'll do my research off other posts, & Louis's videos and see if I can solve this puzzle on my own : ) You'll probably be hearing back from me, LOL.

I do get the dong and seen it working, so my hopes are high. It's not a rush job or anything.

Question: Do I have to have the fan, battery and screen connected for testing around? Or just the battery and screen?
 
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Tony Tone

Tony Tone

Member
Ok, so no enables on U8330, only the VCC. All of those come from the U0500.
The GPU went out on me?
It was fucking working before... Uggg.
 
Tony Tone

Tony Tone

Member
Checked with flash light. There is no image.

At first there was a fully bright working screen with image, then the backlight went out, then the image went out. Still dongs. I need to test with a good know screen first I imagine and external monitor. I will be trying these things next opportunity.
 
Tony Tone

Tony Tone

Member
I don't understand how a good screen could work and then not work. I don't see any damage to cable or connector. I do work with the battery disconnected of course. I've changed many of bare LCD's without issues and many lids also. Never seen one up and die like this. There was no liquid around this area. But I put in a new screen and now is all good : )
Thanks Duke : )
 
Tony Tone

Tony Tone

Member
I'm guessing I may have had on crooked or something and blew this bad boy out. I'll try a new cable and refurbish it with a new LCD. Otherwise, this bad boy is working now - SOLVED : )
 
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