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poor reception after replacing the charging module

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m4rtin86
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(Last edited by m4rtin86; 4th September 2014 at 12:11 AM.)
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Question poor reception after replacing the charging module

I had charging problems with my Samsung Galaxy S II I9100. I fixed those by replacing the charging module, but after that the phone reception is very poor. For example indoors I tend to have from -97dBm(9 asu) to -111dBm(1 asu). Antenna cable is fine(tested resistance) and connects firmly and tight both to main-board and charging module. However, I guess the ~5 USD charging module I ordered from eBay is faulty and that's what's causing the reception problems. Has anyone experienced such behavior? In addition, could somebody technically explain why is it needed to connect the antenna cable both to main board and charging module?
 
keithross39
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There are 4 different versions of that board.....I doubt that the board is faulty, just that you may have brought the wrong version.....the lack of reception strength is one of the symptoms that can occur in a case like this....
See this thread.....
http://forum.xda-developers.com/show....php?t=2335961
for an explanation of how to find the right version.

Sent from my GT-I9100 using XDA Free mobile app
 
m4rtin86
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Quote:
Originally Posted by keithross39 View Post
There are 4 different versions of that board.....I doubt that the board is faulty, just that you may have brought the wrong version.....the lack of reception strength is one of the symptoms that can occur in a case like this....
See this thread.....
http://forum.xda-developers.com/show....php?t=2335961
for an explanation of how to find the right version.

Sent from my GT-I9100 using XDA Free mobile app
The problematic one which I replaced was the:

Code:
GT-I9100 REV2.3
R.CA2 2.6
..and the new one is:

Code:
R.BC4
GT-I9100 REV2.3
While they do look visually different(previous one had more resistors and SMD capacitors), they are both revision 2.3. I even tried the trick where one cuts the charging-module into half, but this didn't help in my case. Any suggestions? Should I try to find exactly the GT-I9100 REV2.3 R.CA2 2.6 charging module?
 
keithross39
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I can only answer yes, you should try to exactly match the boards......
Can you post closeup images of the two boards.....i'd be interested in seeing the differences myself.......

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m4rtin86
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Quote:
Originally Posted by keithross39 View Post
I can only answer yes, you should try to exactly match the boards......
Can you post closeup images of the two boards.....i'd be interested in seeing the differences myself.......

Sent from my GT-I9100 using XDA Free mobile app
Closeup image of two boards:

Name:  USB-boards.jpg
Views: 18
Size:  123.7 KB

While both are cut in half, you can clearly see the difference.

By the way, where is the antenna-connector side of charging module connected to? Antenna-connector side of charging module:

Name:  antenna-side.jpeg
Views: 16
Size:  158.6 KB

..is connected to some component on phone chassis through some resistors:

Name:  case.jpg
Views: 16
Size:  28.8 KB

What is this component and why is it needed? Why is antenna connected to this component?
 
keithross39
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I think that's either the WiFi or Bluetooth antenna......
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