acer atc-780A-UR12 Power Supply upgrade problem

[davidr001]

Hi Everyone! First post, so please be gentle.

I purchased an Acer ATC-780A-UR12 computer with the understanding that I was going to upgrade the PSU so that I could run a GEFORCE GTX 1060 video card. I went online and purchased a Corsair CX500 power supply. Installation was easy but the computer will not come on. The fan on the motherboard is spinning. I hear the hard drive spin up, but nothing boots. As described in numerous posts on Toms, I separated the (1) 8-pin EPS connector into (2) 4-pin connectors and plugged that into the CPU 4-pin port. First I thought I had a bad PSU but I purchased a second one and have the same problem. I've installed the old PSU and everything works fine/boots up. The button on the front of the computer should light up when you press it, but nothing boots. Any ideas? Just a shot in the dark, but is there something specific about the voltage to the 4-pin CPU connector that I need to consider when purchasing an upgraded PSU? I tried contacting acer's tech support but they say that they cannot give any advice beyond the fact that a LITE-ON PS-7501-5AE 500W would work. I sent Corsair an email but have not heard back. Thanks again for anyone that can help.

 

[clutchc]

If you have everything securely plugged into the headers, it should be fine like that. Check that the CPU power and 24-pin connector are all the way in. They should snap over the latch on the header. Sometimes if they aren't all the way in, the wires won't make good electrical contact.

I doubt you could have 2 defective new Corsair PSUs, so I'll rule that out.

 

[davidr001]

If you have everything securely plugged into the headers, it should be fine like that. Check that the CPU power and 24-pin connector are all the way in. They should snap over the latch on the header. Sometimes if they aren't all the way in, the wires won't make good electrical contact.

I doubt you could have 2 defective new Corsair PSUs, so I'll rule that out.

Yes, everything is securely fastened and still no luck

 

[clutchc]

Does the system boot up when you remove the gfx card and plug into the board's iGPU?

 

[davidr001]

Does the system boot up when you remove the gfx card and plug into the board's iGPU?

No graphics card has been plugged in YET. I haven't even gotten that far

 

[clutchc]

Is this your Acer?

 

[davidr001]

Is this your Acer?

Yes, it is

 

[clutchc]

1) So nothing at all happens when you push the start button?

2) Have you tried both halves of the 4+4 pin connector? Be sure you have them facing the right way; connector clip facing header locking tab.

3) Is there any noticeable difference between the wiring of the Lite-On and the Corsair 24-pin connectors?

4) If (1) is no, does anything happen if you unplug everything from the PSU except for the motherboard... and disconnect all peripherals from the PC? Including mouse, keyboard, monitor, basically everything.

 

[davidr001]

1) So nothing at all happens when you push the start button?

2) Have you tried both halves of the 4+4 pin connector? Be sure you have them facing the right way; connector clip facing header locking tab.

3) Is there any noticeable difference between the wiring of the Lite-On and the Corsair 24-pin connectors?

4) If (1) is no, does anything happen if you unplug everything from the PSU except for the motherboard... and disconnect all peripherals from the PC? Including mouse, keyboard, monitor, basically everything.

1. Correct, nothing happens except the fan on the CPU is on.
2. Yes, tried both halves. Clipped and secure
3. None, both have 2 yellow and 2 black wires and I attached them exactly the same.
4. No, nothing happens

 

[clutchc]

On (3) I was asking about the 24-pin connectors, not the 4+4 pin connectors.

 

[davidr001]

On (3) I was asking about the 24-pin connectors, not the 4+4 pin connectors.

No, the 24 pin connector is exactly the same and fits perfectly into the motherboard

 

[clutchc]

Well, I guess I've run out of ideas for troubleshooting from afar. You may have to go back to the Lite-On PSU and decide if you want to return yet another Corsair PSU for a refund.

If you can get the CPU fan to spin, it seems the 24-pin cable is working. At least the +12V section of it. The problem may indeed be the 4-pin.
Check the pin-out colors on the Corsair 4-pin connectors again. The yellow (+) wires should be on the side that the latching clip is on. Compare that to the Lite-On's 4-pin. Just wondering if there is some kind of polarity reversal between the header and connector. Yes... I'm grasping at straws here.

 

[David_825]

David,
Did you ever get this issue figured out? I was considering buying this desktop also and being able to upgrade the PSU was one of my concerns.
Thanks

 

[arajay]

I have the exact same problem with the exact same PC model. I got the acer atc-780A-UR12 as a budget gaming rig, but after installing the EVGA 600B PSU the machine doesn't post with minimum components hooked up.

Hooking up everything except the HDD means all system fans run continuously, but the machine still doesn't post. When I connect the the HDD, the fans will come on for a second but then stop, and then this repeats indefinitely.

I have already tried:

• 
  obvious checking of all connections
  tried both sides of the 4+4 connector
  ensuring the rocker switch is active
  using a known working power cable on the PSU
  confirmed GPU passed paper clip test
  reset the CMOS by removing battery
  booting with only integrated graphics

Swapping out the new PSU for the stock PSU restores things to working order but the stock PSU can't support even the old GTX750ti I've got in there.

Has anyone heard of this kind of thing?

PC: https://www.newegg.com/Product/Product.aspx?Item=N82E16883101587

PSU: Nhttps://www.newegg.com/Product/Product.aspx?Item=9SIA25V5XZ4468