Re: A2159 - 820-01598 - Stuck at 5V and am a beginner looking to learn
Well, I put it back on, but don't think I did it very well. Sadly, I am at my peak with this machine/project and must move on. Thanks again for everyones help, I have learned ALOT!
I would however still like to get this laptop fixed, if possible. So if anyone can recommend a good shop - preferably in Canada - that I can ship to, it would be appreciated.
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Re: A2159 - 820-01598 - Stuck at 5V and am a beginner looking to learn
Thats good to hear, thanks!
I will follow those instructions and update once the part comes in (usually 2 days). Fingers crossed it works this time.
In the mean time, it appears that I have lost C6910, C6901 and C6909 during the cleaning. They appear to be non-critical based on the schematic, what are your thoughts?
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Re: A2159 - 820-01598 - Stuck at 5V and am a beginner looking to learn
Thanks for the suggestion on wicking - I don't have a hakko, so the hint was welcome.
I have removed the chip and added pictures of each step (i.e. right after removal with flux on it, after I cleaned that, and then again after wicking). I also attached a picture of the chip bottom.
Let me know your thoughts.
Also, re-orderd a couple more U6903...
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Re: A2159 - 820-01598 - Stuck at 5V and am a beginner looking to learn
Ok. Correct me if I am wrong, but the only way I can have 12 V both in and out of this chip is if there is bridging of the balls, no?
Also, if a pad is torn off, wouldn't that mean that the connection would stop the current from moving through and thus no reading on the exit?
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Re: A2159 - 820-01598 - Stuck at 5V and am a beginner looking to learn
Hi all, sorry for the delay, I was away on work last week, but back now
@reformatt, can you please point out the pads that look particularly poor. Do you have any recommendations on how I can clean this up further, or test for the broken pads?
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Re: A2159 - 820-01598 - Stuck at 5V and am a beginner looking to learn
Wow, that was hard! Those resistors are so small - I can't believe I didn't lose any (pic attached).
In any-case, here are the updated readings:
R6910: 360 kOhm
R6911: 115 kOhm
R6912: 10.4 Ohm
R6913: 0 Ohm/OL
The resistors are all to spec, so is it a chip issue still?...
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Re: A2159 - 820-01598 - Stuck at 5V and am a beginner looking to learn
I don't understand it, but voltage to ground of C6912 @ pin 1 is 12.3 V steady. Same as the input voltage to the chip measured @ C6909...
So the chip is acting as a wire now? Furthermore, according to the [URL="https://www.ti.com/lit/ds/symlink/tps62180.pdf?ts=1673302057365&ref_url=https%253A%252F%252Fwww.ti.com%252Fproduct%252FTPS62180"]TPS62180 spec sheet[/URL],the max allowable output is 7V.
So I guess we have two problems now, short after circuit and perhaps this...
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Re: A2159 - 820-01598 - Stuck at 5V and am a beginner looking to learn
Power supply came today, just couldn't justify pulling the trigger on a thermal camera... will update later today, thanks!Last edited by Stiffmesiter; 01-09-2023, 01:27 PM.
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Re: A2159 - 820-01598 - Stuck at 5V and am a beginner looking to learn
Ok, removed R6934 and R6935
R6934/6935 @ pin 1: 1.85 Ohms
R6934/6935 @ pin 2: 390 kOhms
Ahhhh, makes sense. I guess from these readings, it suggests that the short is further downstream?
I have 99.9% isa. I will amazon a power supply now.
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Re: A2159 - 820-01598 - Stuck at 5V and am a beginner looking to learn
Understood.
Here are the attached readings:
U3100:
PP3V3_UPC_XA_LDO: 3.34 V @ Pin 1 on C3108
PP1V5_UPC_XA_LDO_CORE: 1.58 V @ Pin 1 on C3105
U3200:
PP3V3_UPC_XA_LDO: 1.26 V @ Pin 1 on C3208 *
PP1V5_UPC_XA_LDO_CORE: 0 V @ Pin 1 on C3205 **
I assume this mean U3200 needs to be replaced?
If I can ask an explanatory question: Why/how did you jump from U6903 to the USB controllers? From the values...
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Re: A2159 - 820-01598 - Stuck at 5V and am a beginner looking to learn
Ok, so post replacement update. I think it worked, since amp meter is showing different results, which I consider progress.
[B]New state:[/B]
Amp meter: 5.12 V at 0.19A
PPBUS_G3H = 12.3 V @ Pin 2 on F7000 (same)
PP3V3_G3H = 0 V @ Pin 1 on C7612 (same)
PP3V3_G3H_RTC = 0.5 V @ Pin 1 on C3100 (different)
U6903 readings:
- 12.25 V @ Pin 1 & 2 on R6900 (same)
- 12.25 V @ Pin 1 on C6909 (same)
- 0.45 V @ Pin 1 on L6900...
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Re: A2159 - 820-01598 - Stuck at 5V and am a beginner looking to learn
@mon2
Alright, so I bought two chips and they came in today. I practiced on an old laptop I hard around, but not going to lie, the chip placement and size of U6903 really made me punch above my weight on this one. I could use some spot checking on how I did (I am writing this reply while the board is in the ultrasonic cleaner, so I haven't tested the results yet, fyi).
In a recap, I followed this video by Louis as a primer ([url]https://www.youtube.com/watch?v=btEkPI5wJTg&t=429s&ab_channel=LouisRossmannRe-UpFULLQUALITY[/url])....
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Re: A2159 - 820-01598 - Stuck at 5V and am a beginner looking to learn
@xtcfreak - I completely agree and thanks for jumping in. After mon2's first response I made a reminder in my notes to ask the same thing. I have so many questions and there is so much domain knowledge to infer.
@mon2
In diode mode, the resistance of L6900 is 0.69 MOhm (Mega!?! does that unit my multimeter is spitting out make sense? Is it that large?).
I am not entirely sure what you mean by this: "It is possible for the regulator to shutdown if the feedback...
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