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CidiRome
Member
Last Activity: 09-21-2023, 08:13 AM
Joined: 01-26-2015
Location: Vieira de Leiria
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  • Re: Xiaomi Roidmi EVE Pro battery died!

    Hello.

    I know that it will work if I bypass it, because I get voltage in the cable if I short it with the tweezers.

    I ordered it to replace.

    Cheers.
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  • Re: Xiaomi Roidmi EVE Pro battery died!

    Hello.

    Please check the attached picture.

    Hope it helps someone else.

    Cheers....
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  • Re: Xiaomi Roidmi EVE Pro battery died!

    Hello.

    Thank you for trying to help.
    It seems that the issue is this component that Sorin is referring to in this Video:
    [url]https://www.youtube.com/watch?v=zVGDk0Ju0LM&pp=ygUFZDZzYzQ%3D[/url]

    I will try to dig one from the battery bucket.

    Cheers.Re: Xiaomi Roidmi EVE Pro battery di...ZzYzQ%3D[/url]
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  • Xiaomi Roidmi EVE Pro battery died!

    Hi there.

    I hope one of you may be able to help me.

    My Xiaomi Roidmi EVE Pro battery died.
    I disassembled the battery and tested the cells to find 2 dead and other 2 almost dead.
    I then dug some batteries from my notebook battery bucket and recovered 8 cells to rebuild the battery.
    Yet I can't get the BMS to start working again: the output is 0 Volts and it won't charge either.
    Did not try to put it in the robot yet, but I don't think the robot will reset the BMS...
    The current cell balance is good with a total voltage around 14.5V....
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  • Beeping Gigabyte H87-HD3

    Hi.

    I'm trying to repair a Gigabyte H87-DH3 that beeps (plenty).

    The beep code are strange (I'm attaching a zip containing two files with it)... The second file is the latest and it is was the board is presently doing.

    I've tried anything I can remember (Bios Reset, force backup bios, different CPU, different Memory, different Dimm slots/configurations, with/without external graphics, etc), but I don't have a clue of what the beeping means.

    At the beginning the problem was intermittent and it would work sometimes, but presently I cannot boot...
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    Last edited by CidiRome; 06-22-2020, 11:09 AM.

  • APC Back-UPS Pro BP1000I Issue.

    Hi there.

    I'm trying to troubleshoot an APC Back-UPS Pro 1000VA BP1000I that is not working correctly and I don't know where to start.

    If I turn it on without load it will start ok and switch to battery without issue, but if I put loads on it it will start beeping and the overload led will turn on despite the load being not even close the the maximum load this UPS can support. (I will try to access the maximum load it will withstand without overloading)

    This is a fairly old UPS, but I know it is good quality and it is better that most newer ones, specially...
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  • Re: NP300e5c Killing input FET after some time.

    Hi.

    With the correct schematic I was able to diagnose a bit more.

    The two resistors (marked in the picture I'm attaching) compose a voltage divider to sense then input DC in. What I noticed was the the bigger (in ohms) resistor resistance was floating, normally going down in resistance along with the temperature going down.

    If this resistor resistance goes down causes the voltage to go up and what I believe happens is that the IC detects that the input voltage is climbing and shuts down...
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  • Re: NP300e5c Killing input FET after some time.

    Hi.

    This is the second time I come across a board with this BQ735 and the previous case I couldn't find a dooner board in my stock where I could get this chip from (I found BQ725, but not one 735).

    This time I was not pointing to this chip, but it would be nice to know it is the culprit before ordering a new one.

    I'm not inclined to do the universal repair of shorting the FET SOURCE-DRAIN pads with a wire like I've seen doing in a few youtube videos for this notebook model...

    If there...
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  • Re: NP300e5c Killing input FET after some time.

    Hi.

    The schematic I have is the one that I'm attaching and I downloaded it from this forum. Based on the P/N BA41-#####A written on it, it matches BA41-01978A written on the board itself.

    Anyway, if this FET is controlled by the charger IC, it doesn't match with the schematic that has a simple passive circuit for this FET's gate (considering it could be a bit different for a N-Channel FET present in this board).

    And is there any reason for this notebook to work flawlessly for a few hours...
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  • Re: NP300e5c Killing input FET after some time.

    Hi.

    I had a few seconds to measure the voltage before it went off (with the same FET) and it is about 25V relative to ground, that would be about 6V relative to Drain.

    I remember measuring the voltage Gate to Drain and it was about 5V.

    When it goes off the voltage is absolute zero (to Ground) or -17V to Drain.

    I thought that it shutting down would be because something ordered it to, but the gate circuitry seems to be very passive... The thing is that I don't know where it is on the...
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  • Re: NP300e5c Killing input FET after some time.

    Hi.

    The Board P/N is BA41-01978A (second Picture of my last post).

    I will try to measure the gate voltage and will get back to you.

    Cheers.
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    Leave a comment:


  • Re: NP300e5c Killing input FET after some time.

    Hi.

    I will try to answer all questions, so hopefully you can help me.

    - I've replaced it again and while working it was drawing up to about 1.5A with the battery out and up to about 2.7A with the battery in (charging).
    - Stops working: they do no short, after what I consider failing they sometimes allow the notebook to turn on, but mostly the greed led turn on and off again. It is worse with the battery in (at least discharged like it is now).
    - I've tried a few FETs that I didn't give much...
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  • NP300e5c Killing input FET after some time.

    Hi there.

    I'm wrapping my head around this Samsung that keeps killing Q10 (the first FET in the 19V power line) after a few minutes at least 15 (this last time I was not close to it when it went down).

    I've seen some youtube videos where they just short this FET, but I don't like this kind of approach: if the FET is there it is for some reason that I may or may not even understand.

    As I didn't find the same exact model FET to replace, I've scavenged other boards for FETs with similar values, but they keep failing.

    There must be something...
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  • Re: Replacing 11N120CND with IRG4PH50UD

    Hi.

    I didn't think about that because they are quite easy to find, any way.

    I attach the datasheets now.

    Cheers....
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  • Replacing 11N120CND with IRG4PH50UD

    Hi people.

    I'm trying to diagnose a 3000VA UPS that has 3 11N120CND blown and also a few other minor components.

    Can I use IRG4PH50UD to replace 11N120CND at least for testing proposes or even permanently?

    I've been trying to compare the datasheet and the most obvious specs seem to be close enough, but I would like your opinion about this.

    Also the IRG4PH50UD were salvaged from an older APC UPS that I couldn't repair, so they should be of decent quality and recycling is always good.

    Cheers.
    See more | Go to post

  • Re: Trouble with Daker DK 3000 UPS

    Hi.

    Thanks for the information.

    About this ups fan problem, even with the "two-fan-hack" I made for testing, it will only start-up about half of the times, the other half it will fail the start-up with error 14.

    About the resistor you mentioned, is it possible that it would be located at the controller board? (remember that this controller board would give the same error in the other UPS that was working correctly with it's own controller board)

    For my service, I have two APC Smart UPS...
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  • Re: Trouble with Daker DK 3000 UPS

    Hi.

    I'm not 100% sure this UPS is that kind of crap. This is an 3000VA Online UPS from a brand that presently is part of LeGrand.

    I've seen plenty of that crap UPS (mostly mustek) that I don't even bother to repair when the issue is more than a dead battery.

    Cheers.
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  • Re: Trouble with Daker DK 3000 UPS

    Hi.

    About the failed diode, that situation was was in the previous UPS, I replaced it and is working correctly.

    In the second UPS:

    - I'm still making tests, but, in the present UPS the FAN AMP rating seems to be important. I hooked another fan in parallel and it is now working.

    - I mentioned before that this UPS has a vibration sound, it comes from somewhere in the red circle of the picture I'm attaching. What would be the most probable culprit component?

    Cheers....
    See more | Go to post
    Last edited by CidiRome; 03-17-2017, 11:50 AM.

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  • Re: Trouble with Daker DK 3000 UPS

    Hi.

    If the small transistor have to be close from the fan header pins, then both UPS would have the same problem.

    I was getting the fan error with both UPS but only with one controller board (pictures 20170220_182313.jpg and 20170220_182341.jpg in the zip file, this pictures are of the board that works correctly), the only difference between the boards is the firmware version.

    Presently one of the fans is of a lower AMP rate and this also happened with a different fan of the other UPS. Can it be that the different...
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  • Re: Trouble with Daker DK 3000 UPS

    Hi.

    Sorry.

    The bad component was a diode RHRP8120 (I found it by comparing the two units, but a close up checkup paying more attention would eventually find that bad diode).

    About the fans, I also thought about that, but...

    Cheers.
    See more | Go to post
    Last edited by CidiRome; 03-16-2017, 12:58 PM.

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