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DenK replied to Acer Aspire 5 A514-55 - won't power on, no charger LED, battery not flat - usual suspects?

in Troubleshooting Laptops, Tablets, and Mobile Devices

12-18-2024, 03:00 AM
Pin 4 (ACDRV): 25V

Knowing now that ACDRV drives the DC-IN MOSFETS, I then measured the gate voltage of those FETS.

[URL=filedata/fetch?id=3530854&d=1734512216][ATTACH=JSON]{"alt":"Click image for larger version Name:\tDC-in MOSFET, AC sense resistor - annotated2.jpg Views:\t0 Size:\t1.45 MB ID:\t3530854","data-align":"none","data-attachmentid":"3530854","data-size":"medium"}[/ATTACH][/URL]

MOSFET A: 17.4V
MOSFET B: 25V
MOSFET C: 25V

Which suggests...

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DenK replied to Acer Aspire 5 A514-55 - won't power on, no charger LED, battery not flat - usual suspects?

in Troubleshooting Laptops, Tablets, and Mobile Devices

12-18-2024, 02:04 AM
On a whim I measured the resistance of (what I believe to be) the AC current sense resistor (see post #15, [B]PRB3[/B]). To my surprise, it measured 1R (not 0.01R as I was expectng). Taking a closer look at the component it appears that it is indeed supposed to be a 1R resistor. In which case I wonder if it still could be the AC sense resistor?On a whim I measured the resistance of (what I believe to be) the AC current sense resistor (see post #15, [B]PRB3[/B]). To my surprise, it measured 1R (not 0.01R as I was expectng). Taking a closer look at the component it appears that it is indeed

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DenK replied to Acer Aspire 5 A514-55 - won't power on, no charger LED, battery not flat - usual suspects?

in Troubleshooting Laptops, Tablets, and Mobile Devices

12-18-2024, 01:50 AM
No problem at all, happy to provide whatever info I can 😄

1) pin 24 (REGN): 6V
2) pin 25 (BTST): 5.7V

(ok I misread your post, missed out pin 4 - will do that soonest!)...

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DenK replied to Acer Aspire 5 A514-55 - won't power on, no charger LED, battery not flat - usual suspects?

in Troubleshooting Laptops, Tablets, and Mobile Devices

12-18-2024, 12:56 AM
Hi [USER="321697"]alfredposadas09[/USER], I've finally managed to get the measurements you asked me to check. I tested with AC and on battery, and the numbers are "AC / Battery":-

1) pin 28 (Vcc): 19.0V / 16.0V (Battery voltage also 16V)
2) pin 6 (ACDET): 2.63V / 12mV
3) pin 16 (BST_STAT): 0.6V (did you mean 6 or 0.6?) / 380mV
4) pin 5 (ACOK): 3.3V / 0V

As an aside, I measured 19.0V on both sides of the missing PR254... it's a 0805 SMD component, based on the size of the hole in the solder, and I'm wondering if I should try shunting...

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DenK replied to Acer Aspire 5 A514-55 boardview and schematics request

in Schematic Requests ONLY!

12-18-2024, 12:40 AM
Hi, sorry so I'm not sure what you mean, is it that you are only able to access one of the 2, and can't access the other anymore, or you're only willing to share one of the 2? 😅...

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DenK replied to Acer Aspire 5 A514-55 - won't power on, no charger LED, battery not flat - usual suspects?

in Troubleshooting Laptops, Tablets, and Mobile Devices

12-10-2024, 08:02 PM
Of course, certainly~ was just mentioning by the by

Brief updates:

1) Discovered battery had self-discharged to mV level in the last few days! So I'm unable to test on battery power now as well

2) Having said that, I confirmed there is continuity between the battery +ve connector pin on PCB and pin 28 (Vcc) of the charger IC, so if the battery was working, current should flow up until at least the pin.

3) I think I've figured out the actual AC current sense resistor. Pads connect to the charger IC's pins 1 and 2, it matches the value (0.01R)...

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DenK replied to Acer Aspire 5 A514-55 boardview and schematics request

in Schematic Requests ONLY!

12-10-2024, 07:45 PM
Hi! Thank you~ But, if one had to choose, wouldn't the schematic be the generally more useful one? 😅
Can we trade the board view for the schematic then? Since if I could only access 1 of them, then definitely that's the one I do need for troubleshooting 😄🙏🏼

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DenK replied to Acer Aspire 5 A514-55 - won't power on, no charger LED, battery not flat - usual suspects?

in Troubleshooting Laptops, Tablets, and Mobile Devices

12-10-2024, 09:23 AM
Thank you mon2, I will check that tomorrow and report back!

But as I mentioned in my initial post (item 4(e)), there's a positive voltage on the battery connector's +ve pins with no battery attached, only AC adapter...

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DenK replied to Acer Aspire 5 A514-55 - won't power on, no charger LED, battery not flat - usual suspects?

in Troubleshooting Laptops, Tablets, and Mobile Devices

12-10-2024, 09:20 AM
Sooo... I did a quick test for continuity from pins 1 and 2 of the BQ24800 (per attached photo in case I got it wrong) to either pad of the missing component. No continuity

I might be doing something wrong, will try again tomorrow. I'm quite sure there must be [I]something[/I] across those pads.

[ATTACH=JSON]{"data-align":"none","data-size":"medium","data-attachmentid":3525422}[/ATTACH]Sooo... I did a quick test for continuity from pins 1 and 2 of the BQ24800 (per attached photo in case I got it wrong) to either pad...

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DenK replied to Acer Aspire 5 A514-55 - won't power on, no charger LED, battery not flat - usual suspects?

in Troubleshooting Laptops, Tablets, and Mobile Devices

12-10-2024, 08:37 AM
Thank you mon2! It looks like we arrived at the same solution and our messages crossed. 😀...

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DenK replied to Acer Aspire 5 A514-55 boardview and schematics request

in Schematic Requests ONLY!

12-10-2024, 08:35 AM
Thank you so much noname! Would you happen to have the schematics as well? ...

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DenK replied to Acer Aspire 5 A514-55 - won't power on, no charger LED, battery not flat - usual suspects?

in Troubleshooting Laptops, Tablets, and Mobile Devices

12-10-2024, 08:30 AM
On another note though, would a missing current sense resistor explain why the laptop won't power on even on [I]battery [/I]power? (and battery measures around 14V+ so it doesn't seem flat)On another note though, would a missing current sense resistor explain why the laptop won't power on even on [I]battery [/I]power? (and battery measures around 14V+ so it doesn't seem flat)On another note though, would a missing current sense resistor explain why the laptop won't power on even on [I]battery [/I]power? (and battery measures around 14V+ so it doesn't seem flat)

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DenK replied to Acer Aspire 5 A514-55 - won't power on, no charger LED, battery not flat - usual suspects?

in Troubleshooting Laptops, Tablets, and Mobile Devices

12-10-2024, 08:17 AM
Thank you mon2!

I did find the battery charger/controller prviously, as I was preparing to go through the troubleshooting process in piernov's guide before I discovered this.

It's a [B]BQ24800[/B]. Product page is here [URL]https://www.ti.com/product/BQ24800[/URL], but for some reason they only have a brief datasheet without the usual pinout chart - full datasheet upon request. I've attached a copy of the brief sheet for convenient reference, while I continue hunting for the full datasheet.

[B]Edit:[/B] Ha! The datashet for the eval board for this controller...

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DenK replied to Acer Aspire 5 A514-55 - won't power on, no charger LED, battery not flat - usual suspects?

in Troubleshooting Laptops, Tablets, and Mobile Devices

12-10-2024, 07:24 AM
So I removed the board and examined the underside. I found what looks like signs of a missing component. I could be wrong, but looking at the page linked to by piernov, could this component be the AC input current sense resistor? Judging by the "R" designation and large lands on the PCB.

[ATTACH=JSON]{"data-align":"none","data-size":"medium","data-attachmentid":3525295}[/ATTACH]...

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DenK replied to Acer Aspire 5 A514-55 boardview and schematics request

in Schematic Requests ONLY!

12-10-2024, 07:21 AM
I removed the board and found what might be the board model:-...

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DenK started a topic Acer Aspire 5 A514-55 boardview and schematics request

in Schematic Requests ONLY!

12-08-2024, 07:24 AM
Acer Aspire 5 A514-55 boardview and schematics request

Dear all, would anyone happen to have the boardview and schematics for the Acer Aspire 5 A514-55? I see a thread for the A514-52K but the components (and designations) don't seem to match up.

I have attached photos of the board's markings, as I'm not sure which is the board's model number.

Thank you all in advance!

[URL=filedata/fetch?filedataid=365124][ATTACH=JSON]{"data-align":"none","data-size":"medium","data-attachmentid":3523880}[/ATTACH][/URL]
[URL=filedata/fetch?id=3523877&d=1733664491][ATTACH=JSON]{"alt":"Click...

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DenK replied to Acer Aspire 5 A514-55 - won't power on, no charger LED, battery not flat - usual suspects?

in Troubleshooting Laptops, Tablets, and Mobile Devices

12-07-2024, 09:22 AM
Thank you piernov! That is a detailed and educational post, and I'm still digesting it. I'll also head over to the schematics forum to see if anyone has the schematics for this laptop model and try to apply the troubleshooting steps you'd set out in the post!...

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DenK started a topic Acer Aspire 5 A514-55 - won't power on, no charger LED, battery not flat - usual suspects?

in Troubleshooting Laptops, Tablets, and Mobile Devices

12-06-2024, 01:29 AM
Acer Aspire 5 A514-55 - won't power on, no charger LED, battery not flat - usual suspects?

Dear all, I am trying to troubleshoot an Acer Aspire 5 A514-55 that won't power on. I'll describe the symptoms and my findings so far, and I would like to seek guidance and suggestions on possible suspects in terms of cause/component failure. My initial thoughts are battery charger IC and/or ideal diode/MOSFET (that switches between incoming DC and battery power), but I could be totally wrong on this.[INDENT]1) Laptop was working fine on battery, then user realised battery was running low. Plugged in AC adapter but noticed it was not charging (LED on AC adapter plug did not light). Eventually...

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DenK replied to New Members - please post your introductions here

in Announcements & Related News

12-06-2024, 12:29 AM
Hi all! I have had a life-long interest in computer hardware - my first computer was an 8088 back in elementary school and my fascination with circuit boards started soon after! To this day I love to build, repair and/or otherwise work on computers, from laptops to servers. However, I'm still a beginner at circuit/component-level troubleshooting and repair, and I hope to learn from the veterans in this forum!

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