Problem: Acer ATC-605 desktop (ATC-605-UR13) in forever reboot before POST.
Cause: Malfunction 300W power supply unit (My best guess: Not enough power during bootup)
Solution: Replace the 300W power Supply unit with another 380W power supply unit
It's a love and hate to Acer computer. The love is the price really reasonable. And the hardware quality would make you hate Acer never want to buy from the brand again.
I bought a refurbished "Acer ATC-605-UR13 (i.e. Aspire TC 605) Core i5-4440 10GB 1TB WiFi HD 4600 DVDRW Windows 8.1 Desktop" in 2014. In the very beginning, I found it rebooted by itself once in a while. Later after upgrading it to Windows 10, it worked sometimes and did not boot up most of the time. When it was unable to boot up, the screen is blank, no beep code, no POST (Power on self Test) screen. The CPU FAN spinned one time in 3-5 seconds. Then, the computer turned off itself and rebooted itself and started the reboot cycle again. This is a very frustrated experience.
Since I'm living a busy life and I have other notebook to use, I leave it on the corner of the desk until recently. I was thinking that I'm lacking a reliable desktop to store family photos/videos. I pulled the Acer desktop out and see if the booted problem can be fixed.
The reason I wanted to fix it is: the CPU i5-4440 is amazing fast (6398 passmark score which it is faster than a lot of low-end i7 CPUs, per reference in cpubenchmark.net). It has plenty of ram 10GB !!!!!!!. It can be upgraded and running to Windows 10 with no issue at all when it is booted up.
I'm not a hardware person. What I can do it is to observe the obvious symptoms and trying to narrow down to it. I tried below list of things:
- Upgrade the firmware to the latest one and reboot- Remove all ram and reboot- Replace the power supply and reboot- Unplug all the harddisk and cd-rom and reboot- Unplug ram and reboot- Remove secure boot from BIOS- Disable UEFI from BIOS- Clear the CMOS using battery removal or jumper- Disable most of the thing not needed from bios. - Reinstall the Windows 10 (from Reset command)- Google the sympotms and tried out all the solutions from the Web.
All of the above never can get ride of the reboot loop problem. Last thing I tried is to use the POST Diagnostic card to see the code where the boot up process stopped before the POST. The POST Diagnostic card is in progress of delivery from Ebay. Before it arrived, I found that when I removed the harddisk and DVD-ROM connection and after the CMOS is cleared. Sometimes the system can be rebooted up and can be used until the PC is shutdown. And the reboot problem come back again in next reboot.
When looking from the web solutions, I noticed that the i5-4440 CPU consumed 82W power. And the default power supply got 300W power. 1/3 of power already going to the CPU. And sometimes, when the harddisk and DVD-ROM were disconnected (power and signal cable), the PC can be booted after POST. I was thinking two issues. Could it be a short circult protection from the power supply. Or simply not enough power during the PC boot up process. So, this Sat. morning, I went to Frys to buy a 380Watt power supply ($12.99 after rebated) and give it a shot. Volla, this is the first time in the last months the PC can be booted up with no problem. The 380W PSU resolved the problem YAY.
I don't know the real cause yet. I have a friend who works as architect to design PSU. I'll certainly go to him and consult him why.