Acer Aspire TC-780 Will not turn on after replacing CPU Fan

Techflash
Techflash Member Posts: 23 Troubleshooter
in Aspire and Veriton Desktops

I previously had an issue with the stock CPU fan:

https://community.acer.com/en/discussion/684089/acer-aspire-tc-780-cpu-fan-will-not-spin

So I replaced it. Now after replacing it, the system does not power on correctly. Here's what works and what doesnt:
Power Light: Off
CPU & Case Fan: Spinning
HDDs: Spin up but don't do anything
USB Peripherals: Turn on, but do nothing. (e.g. pressing numlock on keyboard doesn't turn on numlock LED)
Video: Nothing
PC Speaker: Nothing

Does anybody know what these symptoms mean?

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Answers

  • Larryodie
    Larryodie Member Posts: 1,658 Community Aficionado WiFi Icon

    Do you get ANY error BEEPS ?

    I would do a detail visual with the power cord unplugged.

    Look for any loose/unseated cable.

    BTW. Did you unplugged when replacing the fan ??

    Next steps if no beeps.

    Reset the BIOS via the jumper or unplug and hold the Power button for 30 sec or more. Then retry.

    Good Luck.

  • Techflash
    Techflash Member Posts: 23 Troubleshooter
    edited May 2023

    No error beeps.

    Give me a bit to get a good picture of everything.

    Both me and my dad have already tried looking at every cable. Everything seems fine.

    Yes, I unplugged everything, I had to remove the entire board. The fan uses a push pin style mounting system, so I had to fully remove the board from the chassis, and then I had to remove the backplate, so I used hot air (it was set it to 50C, so it couldn't possibly be hot enough to damage the board) to melt the glue, and the I just kinda pried it off with a flathead after I loosened it with the hot air.

    I will try resetting the CMOS using that, however, I already had the CR2032 out all while replacing the fan (at least 15 minutes), so I imagine any data in the CMOS has already been cleared.


    I will report back with more info once I perform each of those steps.

  • Techflash
    Techflash Member Posts: 23 Troubleshooter
    edited May 2023
    PXL_20230514_163757620.jpg
    PXL_20230514_163815427.jpg
    PXL_20230514_163833435.jpg

    Alright, one at a time:
    Here's a pic of the PC with the Side and Front panels removed with a few changes:
    - I have removed the Front I/O Assembly, it has always worked like this for me, I did this as I simply never used any of it's features (audio, extra USB, or SD Reader), and it took up a lot of room in the case. I usually use a USB Fan to blow air on the dual hard disks that you can see in the pic. and the removed front panel gives extra air flow.
    - I have unplugged the SATA power and data cables from both HDDs, as they covered much of the board when in the photo. These were plugged in while testing, and they are not necessary to boot, however if they are the problem, that will be a huge issue, as one of my uses for this PC is as a NAS for storing large files.
    - I have disconnected the WiFi & BT card, as I was simply unable to get those tiny white and black wires back in (I can't tell exactly what they are, antennas? Ground? [One of them goes to the back of the case, the other to the front])
    - Included the USB Fan in the picture, it was not like this during testing, but simply to show what it would be like when finished. While not necessary to function, it is helpful, as those hard drives get very warm.

    I have included 3 photos:
    1. Pulled back view of the entire board.
    2. Close up of the right (MB power, Power button, SATA [disconnected], Front I/O [disconnected])
    3. Close up of the left (CPU power)

    If you would like any additional info, please let me know. I would love to get this thing running again!

  • Techflash
    Techflash Member Posts: 23 Troubleshooter
    edited May 2023

    OK, step #2, CMOS Clear jumper:
    I switched the jumper to cover the bottom 2 pins as suggested by the manual:
    ```
    Use the CMOS1 jumper to clear the CMOS data.
    • 1-2 position: Normal operation (default)
    • 2-3 position: Clear CMOS data
    ```
    I plugged the AC Power in, and the USB keyboard flashed for a second. I then held the power button in for 40 seconds, nothing happened.
    I unplugged the power, waited a second for it to disipate, then switched the CMOS jumper back and tried to power on again.
    Same issue. No power LED. No Video. No Beeps. Just the fans (and USB).

  • billsey
    billsey ACE Posts: 34,101 Trailblazer

    OK, no beeps and no POST means either POST doesn't start with initialization or the memory passes but it doesn't load the rest of the BIOS. Any chance the CPU isn't set back in right?

    Click on "Like" if you find my answer useful or click on "Yes" if it answers your question.
  • Techflash
    Techflash Member Posts: 23 Troubleshooter

    It's unlikely, but I'd be glad to check. Give me a bit to take off the cooler and reseat it.

  • Techflash
    Techflash Member Posts: 23 Troubleshooter

    Oh no. I just checked, here's all I got:
    After a careful examination of the pins on the socket, they're all fine. HOWEVER, I remember clearly from previous usage, this PC makes a sound if you boot it with no RAM installed. It simply gives a long continuous beeeeeeeeeeeeeeeeeeeep. When reassembling this time, I forgot to install the RAM back, and when booting it, it doesn't make a sound.
    This makes me think that it isn't even getting long enough in the boot process to get to the memory test.
    I'm starting to think that this is very high level problem, things that I'm starting to consider might be at fault:
    - Whole motherboard failure
    - CPU failure
    - BIOS ROM failure
    - Any other issue that could crop up between the board, BIOS, and CPU.

    If it does turn out that this machine is simply dead (or if at least the CPU is dead), I would probably simply find another PC to use as a server. Also, if that would be the case, does Acer offer a program to recycle old machines such as this?

  • Larryodie
    Larryodie Member Posts: 1,658 Community Aficionado WiFi Icon

    Maybe a Ram is bad as the continuous beep is BAD RAM but possibly the RAM when installed is stalling the system leaving it unable to boot.

    Have you tried booting with either or.

    Looks like you have 2 ram ? Maybe a factory and a Corsair with heat sink add-on ?

    Try booting with the Corsair removed and/or with the Corsair in the #1 position.

    I see where some heat evidence in the 2nd picture of the area next to the Ram and under the fan ? That could be possible from the hot air ?

  • Larryodie
    Larryodie Member Posts: 1,658 Community Aficionado WiFi Icon

    Also maybe tried to reset your bios to default IF the one RAM boot doesn't help.

    https://www.manualslib.com/manual/1665220/Acer-Aspire-Tc-780.html?page=110

  • Larryodie
    Larryodie Member Posts: 1,658 Community Aficionado WiFi Icon

    I MISREAD your post as you said NO beeping sound. Sorry.

  • Techflash
    Techflash Member Posts: 23 Troubleshooter
    1. I get no beep at all currently. I'm saying that's something I remember should be there with no RAM.
    2. Yes, I have cleared the CMOS, see this comment I made:
    3. https://community.acer.com/en/discussion/comment/1201524#Comment_1201524
    4. Yes, that is correct, there is no beeping sound, no power light, and no display output. Only the CPU and Case Fans spin up, and USB peripherals turn on.

  • Larryodie
    Larryodie Member Posts: 1,658 Community Aficionado WiFi Icon

    Were you able to default the BIOS as

    Connect the AC power cord to the system

    Press the power button

    During POST,

    press Delete to access the Setup Utility.

    . Press F9 to load the system default values.

    . Press F10 to save the changes you made and close the Setup Utility.

  • Larryodie
    Larryodie Member Posts: 1,658 Community Aficionado WiFi Icon

    It may be F2 or even F1 instead of the delete KEY.

  • Techflash
    Techflash Member Posts: 23 Troubleshooter

    It is delete, and I get no POST whatsoever, even taking out the memory, which should give a POST error, does nothing, it has the same issue of no power light, no video, and no beeps.

  • Larryodie
    Larryodie Member Posts: 1,658 Community Aficionado WiFi Icon

    I've looked over your pictures good and don't see any cracks or anything unusual except the smudge board near the memory IC.

    Is that area, too hot to touch ??

    Another thing is to look on the bottom of the board for any cracked pc circuits.

    I don't see any cracks around or near the mounting screws.

    Good Luck.

  • Techflash
    Techflash Member Posts: 23 Troubleshooter

    I can't find any smudges anywhere, if you could mark the area where you're seeing a smudge, I can send a better picture of it.
    I'm not going to try to touch it, as I don't have anything that could dissipate the electricity if I accidentally touch a solder point with power running through it.

  • Larryodie
    Larryodie Member Posts: 1,658 Community Aficionado WiFi Icon

    This picture, to the upper left of the ram.

    smudge.jpg

  • Techflash
    Techflash Member Posts: 23 Troubleshooter

    Ah. I'm currently away from home, but I'll take a look and try to get a clearer picture when I'm back. That's going to take about 4 hours.

  • Techflash
    Techflash Member Posts: 23 Troubleshooter

    I just checked, it was just the angle of the light, there's no smudge there.

  • Larryodie
    Larryodie Member Posts: 1,658 Community Aficionado WiFi Icon

    I'm clueless unless you cracked a pattern on the bottom side when you " Yes, I unplugged everything, I had to remove the entire board. The fan uses a push pin style mounting system, so I had to fully remove the board from the chassis, and then I had to remove the backplate, so I used hot air (it was set it to 50C, so it couldn't possibly be hot enough to damage the board) to melt the glue, and the I just kinda pried it off with a flathead after I loosened it with the hot air."

    https://community.acer.com/en/discussion/668148/does-the-aspire-tc-886-motherboard-have-pwm-for-cpu-fan

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