Re: Asus X554L No Power
Hi @mon2
Reading is 470
Marking is BQ735. I make a search, it is Texas Instruments bq24735 Li+ Battery SMBus Charge Controller....
StefanNg
Member
Last Activity: 01-31-2025, 04:18 AM
Joined: 10-28-2022
Location: Kuala Lumpur
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Re: Asus X554L No Power
I watch some asus main board repair video. Is PL8801 part of the battery charging circuit? If yes, then 3.19v seems to be too low, it need to be around 12v.
IC PU8101 +3VAO is connected somewhere near to IC PU8800, which may work together with PL8801? Or could it be some problem near to EC U3001? Is there a way to further checking?
I still haven't find the way out yet. Hmm..... any suggestion?Last edited by StefanNg; 11-13-2022, 07:06 PM.Leave a comment:
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Re: Asus X554L No Power
Hi @mon2
I follow your instruction
PL8003 60.4 Ohm
PL8501 6.2 Ohm
PL8502 6.2 Ohm
PL85xx is located close to GPU U7001, PL8003 is located close to processor U0301Leave a comment:
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Re: Asus X554L No Power
I temporary patch up PSL8104, connect adapter and took big coil voltage measurement on the main board
PL8003 0v
PL8101 5v
PL8102 3.32v
PL8201 1.09v
PL8301 1.37v
PL8501 0v
PL8502 0v
PL8801 3.19v
Compare to boardview information, I feel this result looks normal. Hmm..... what else I can check further?🤔Leave a comment:
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Re: Asus X554L No Power
I check on this section previously, I will re-check it again tonight. In previous measurement Pin#4 is +24.3v, Pin#1 is +19.5v. Source voltage is present for both mosfet, +19.5v. Is this measurement sounds OK? Gate voltage is slightly lower but Drain voltage is present.
Just an additional thought. Both mosfet is interconnected for Pin#1 and Pin#4. With power adapter connected, only PQ8801 is check in this measurement?Leave a comment:
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Re: Asus X554L No Power
Please correct me if any point I get it wrong.
I assume dcin mosfet means PQ8801 and PQ8802
The mosfet marking is M0930M, I could not find datasheet, so I don't know which type of mosfet I have. I test it on diode mode, roughly guess where to contact the +ve and -ve probe. I took pin1 as drain, D
______________PQ8801 PQ8802
S(-) and D(+) 16MOhm 16MOhm
S(-) and G(+) 1136kOhm 1030kOhm
G(-) and D(+) 16.5MOhm 16.5MOhm
I have no idea what I am looking at
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Re: Asus X554L No Power
Should I say the rail is powering ON? It receive +3V from PU8101, but the rail voltage dropped to around +2V, there is continuity on it. Because of the voltage drop, power switch is not functioning.
The +3VA is connected to few parts. I need to find a way to narrow down....
Is this main board still worth a try?
Leave a comment:
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Re: Asus X554L No Power
I watched few voltage injection video. Voltage is inject from the point shorted to ground, current injected will flow thru shorted caps, then heat up the bad cap.
In my case, PSL8104 pin2 is not shorted to ground, resistance is 90kOhm. Is it safe to do voltage injection? If not safe, what should I check next?
Thank you.Leave a comment:
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Re: Asus X554L No Power
Hi, mcplslg123
I manage to cut open PSL8104. First time do on a multi layer PCB, so I did it slowly.
+3VAO is now +3.3V, +5VAO 0V (+4.9V if I short the gap I cut on PSL8104), the IC is good. Maybe is a bad news for me because now I need further deal with the whole +3VA rail.
The only safe way to do voltage inject is using a bench top power supply? I don't have it and I will need to learn the correct way to use. While I source for a suitable power supply, I am welcome any suggestions on alternative way to repair the main...Last edited by StefanNg; 11-06-2022, 08:19 PM.Leave a comment:
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Asus X554L No Power
Hi BadCaps
I want to try my first component level repair on this board. It is a Asus X554L with X555LD main board rev. 3.6. I search the forum and online, downloaded any resources available. The boardview I get is not exactly the same, this main board may have many variant, not all component shown in boardview exist on actual board.
The board do not power on, no charging light, nothing. Item already check include
1. MOSFET PQ8801 PQ8802, source +19.5v, drain +19.5v, gate +24.3v
2. Power switch SW5601, +1.96v, below required +3v.
3. IC PU8101 (component... -
Re: New Members - please post your introductions here
Hi BadCaps
I am Stefan from Malaysia. I do simple electronic repairs as a hobby. I noticed that it is very difficult to understand complex circuits even with a schematic. That's why I ended up here, hope to get some guidance to enlighten me.
Best regardsLeave a comment:
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