In the service manual for Galaxy S7 (SM-G930F), step number four in the flow chart for troubleshooting power-on issue is to check the voltage level of a "signal".
I had a very hard time locating this. I didn't understand what it means to check for voltage of something by its signal name, and it's location was not described in the service manual (not that I could see in my four chapter excerpt of the complete manual). Then I learned that this signal name needs to be translated into a test point (TP) ID on the board. This is unlikely to be referenced in a service manual. So unless you have a circuit diagram for the phone, you will have a very hard time knowing what signal name translates to what test point on the board.
In my search for the test point for this signal, I have found where it's located on the Galaxy S2 (GT-I9100). I am sharing it here for sake of comparison but also to enable others to find it too (making "google it" possible), in case someone else is looking for the same thing but for the older phone.
This is where it's at on Galaxy S2:
Then I located the test point for AP_PS_HOLD on the Galaxy S7 Edge (SM-G935F) and also on the Galaxy S7 (SM-G930F) as well. But I'm still not sure if I have the right idea on how to probe it.
This is where it's at on Galaxy S7:
This is where it's at on Galaxy S7 Edge:
My source for Galaxy S2 test point:
Samsung S2 (GT-I9100) Fehlersuche mit Servicemanual
My source for Galaxy S7 Edge test point:
Samsung S7 SM-G935F, AP_PS_HOLD - GSM-Forum
Image source for Galaxy S2:
Samsung Galaxy S 2 (International) Review - The Best, Redefined
Image source for Galaxy S7 and diagrams:
My own photo and snapshots from service manuals.
I could not find a good picture of the Galaxy S7 Edge board for comparison. But the location of the TP7002 is in the same area as for the Galaxy S7 according to the diagram. Also, I only assume that TP7002 serves the same purpose (AP_PS_HOLD) on both the Galaxy S7 and the Galaxy S7 Edge. But it seems that the same test point is used on multiple Galaxy phones, so I suppose it serves the same purpose on all of them. It's just that the location is different and it appears to be protected for some reason on later phone models.
Thanks to this forum, and thanks to SMDFlea, I now have the schematics, and I can confirm that TP7002 is the test point for AP_PS_HOLD on Galaxy S7 (SM-G930F).
Here it is on the schematics:
So now I know for a fact that it can be checked at TP7002. Now here is where I get stuck. As you can see, on the Galaxy S2, the test point looks like a proper test point, in the form of a copper contact pad. But on Galaxy S7 and Galaxy S7 Edge, it looks like it's protected by a layer of paint/coat (I don't know the technical term for it, but you get the idea). So I'm thinking about scratching or scraping that layer off so I can get down to the copper. Is that the right idea here? I have never seen a "test point" looking like this, where it's not conductive, so you can't actually use it for testing. Why would you want to cover it up if it's a test point? This is the first thing I don't understand about this.
If it says to "check the signal", does it mean to use an oscilloscope? Do I need to see what the signal looks like for some reason? Can I not check it with a multimeter? I don't have an oscilloscope.
I am not a repair professional, and I have nearly zero experience with electronics. This is my first time trying to repair something as delicate and fragile as a smartphone, and I am doing my best to avoid making a mistake I can't recover from. So help and advice on this would be appreciated. Thanks!
Check the signal of AP_PS_HOLD = 1.8V
In my search for the test point for this signal, I have found where it's located on the Galaxy S2 (GT-I9100). I am sharing it here for sake of comparison but also to enable others to find it too (making "google it" possible), in case someone else is looking for the same thing but for the older phone.
This is where it's at on Galaxy S2:
Then I located the test point for AP_PS_HOLD on the Galaxy S7 Edge (SM-G935F) and also on the Galaxy S7 (SM-G930F) as well. But I'm still not sure if I have the right idea on how to probe it.
This is where it's at on Galaxy S7:
This is where it's at on Galaxy S7 Edge:
My source for Galaxy S2 test point:
Samsung S2 (GT-I9100) Fehlersuche mit Servicemanual
My source for Galaxy S7 Edge test point:
Samsung S7 SM-G935F, AP_PS_HOLD - GSM-Forum
Image source for Galaxy S2:
Samsung Galaxy S 2 (International) Review - The Best, Redefined
Image source for Galaxy S7 and diagrams:
My own photo and snapshots from service manuals.
I could not find a good picture of the Galaxy S7 Edge board for comparison. But the location of the TP7002 is in the same area as for the Galaxy S7 according to the diagram. Also, I only assume that TP7002 serves the same purpose (AP_PS_HOLD) on both the Galaxy S7 and the Galaxy S7 Edge. But it seems that the same test point is used on multiple Galaxy phones, so I suppose it serves the same purpose on all of them. It's just that the location is different and it appears to be protected for some reason on later phone models.
Thanks to this forum, and thanks to SMDFlea, I now have the schematics, and I can confirm that TP7002 is the test point for AP_PS_HOLD on Galaxy S7 (SM-G930F).
Here it is on the schematics:
So now I know for a fact that it can be checked at TP7002. Now here is where I get stuck. As you can see, on the Galaxy S2, the test point looks like a proper test point, in the form of a copper contact pad. But on Galaxy S7 and Galaxy S7 Edge, it looks like it's protected by a layer of paint/coat (I don't know the technical term for it, but you get the idea). So I'm thinking about scratching or scraping that layer off so I can get down to the copper. Is that the right idea here? I have never seen a "test point" looking like this, where it's not conductive, so you can't actually use it for testing. Why would you want to cover it up if it's a test point? This is the first thing I don't understand about this.
If it says to "check the signal", does it mean to use an oscilloscope? Do I need to see what the signal looks like for some reason? Can I not check it with a multimeter? I don't have an oscilloscope.
I am not a repair professional, and I have nearly zero experience with electronics. This is my first time trying to repair something as delicate and fragile as a smartphone, and I am doing my best to avoid making a mistake I can't recover from. So help and advice on this would be appreciated. Thanks!
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