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Won't boot unless CMOS is reset. Biostar A85W

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Tackle

Registered
Joined
Apr 12, 2013
Hello fellow overclockers!

I purchased the A10-5800k, Biostar A85W combo (with 8GB Ripjaws 1600 and headset) a few weeks back at newegg.

I'm having a strange issue. When I leave my PC sit over night and try to power it on, it does not post/boot. The fans spin and the lights are on. The digital error code is CS or C5. If I hold the power button down, then try to power it on again, the fans spin but no post and the error code screen is blank.

If I reset the CMOS jumper, the PC will boot, but I get a CMOS failed. It loads the OS fine then and I can reboot and turn it off and back on no problem. Once I let it sit over night, I can't boot it again, and it has the CS error code displayed, requiring me to move the jumper to 2-3 then back to 1-2 before it will boot.

I have updated the bios to the latest: BIOS Date: 12/19/12 11:54:51 Ver: 04.06.05, reset to defaults, no over clock.
Also tried re-seating ram and CPU, running wth all pereph. unplugged, disconncted the HDD.


TLDR: Biostar a85w requires CMOS reset to boot if powered off overnight.
Any suggestions?
 
No, it is turned off at night.

The issue only happens if it's been turned off for a long period of time.
 
First I would reset using the battery as well. If that doesn't clear it up Update/flash the BIOS.
 
First I would reset using the battery as well. If that doesn't clear it up Update/flash the BIOS.

I have pulled the battery for 10 minutes and also tried a different one. I did flash the bios to the latest version to try and resolve the issue. Also reset the bios to defualts. Same issue.
 
What kind of peripherals do you have plugged in ? Maybe one of them is preventing the startup.
 
To be more clear:

I am on the PC right now (RDP'd from work). If I shut it off and leave it sit until I get home from work, it will not boot, no post, no bios screen. The fans will spin and the error code will display CS or C5.

If I hold the power button so it turns off, then move the CMOS jumper to 2-3 then back to 1-2, it will power on and run as normal (besides a CMOS fail error, which I would assume is from the reset).

Then I can turn it off and back on and it will work fine.
It only fails to post/blank screen if left sitting for hours.
 
Strange. Have you tried one stick of ram at a time ? Different slots?
 
Might have something to do with your power on settings. You must have it set to wake on LAN. Maybe try with them all disabled
 
Strange. Have you tried one stick of ram at a time ? Different slots?

Currently only have 1 stick (second on the way). I have tried it in different slots, running with no ram (hoping for post at least), and have tried different ram.
 
WOL is not configured, but I had scheduled an automatic power on in the bios (which did not work, did not attempt to start on its own).

I will turn off the auto wake up in the bios and turn the PC off over lunch and see what happens, thx for the suggestion. I haven't figured out exactly how long it takes before it will fail to boot...it's only happened when I leave it off over night and try to power it on in the morning.
 
Update: I rebooted the PC over lunch and it would not post or get to bios. Hung with C5 error code. Needed to reset the CMOS jumper for it to boot. I then upgraded to a newer bios (released a couple days ago), followed proper procedure for flashing and loading optimized defaults. It worked fine but then I shut the PC down while I ate lunch, tried to start it before I left, same C5 error and would not boot/post/no bios screen.

Thinking I might have to RMA it, I've run out of ideas.
 
Have you looked at your manual for the error code specifics?

I think C5 as to do with the enumerater thus a CPU problem... I would think if that truly is the issue no amount of CMOS resets would fix the problem and it would never POST.
 
I found your manual and there is no listing for a "C5" code...

7.3 AMI BIOS BEEP CODE
Boot Block Beep Codes
Number of Beeps Description
Continuing Memory sizing error or Memory module not found
POST BIOS Beep Codes
Number of Beeps Description
1 Success booting.
8 Display memory error (system video adapter)
7.4 AMI BIOS POST CODE
Code Description
10 PEI Core is started
11 Pre-memory CPU initialization is started
15 Pre-memory North Bridge initialization is started
19 Pre-memory South Bridge initialization is started
2B Memory initialization. Serial Presence Detect (SPD) data reading
2C Memory initialization. Memory presence detection
2D Memory initialization. Programming memory timing information
2E Memory initialization. Configuring memory
2F Memory initialization (other).
31 Memory Installed
32 CPU post-memory initialization is started
33 CPU post-memory initialization. Cache initialization
34 CPU post-memory initialization. Application Processor(s) (AP) initialization
35 CPU post-memory initialization. Boot Strap Processor (BSP) selection
36 CPU post-memory initialization. System Management Mode (SMM) initialization
37 Post-Memory North Bridge initialization is started
3B Post-Memory North Bridge initialization (North Bridge module specific)
4F DXE IPL is started
60 DXE Core is started
F0 Recovery condition triggered by firmware (Auto recovery)
F1 Recovery condition triggered by user (Forced recovery)
F2 Recovery process started
F3 Recovery firmware image is found
F4 Recovery firmware image is loaded
E0 S3 Resume is stared (S3 Resume PPI is called by the DXE IPL)
E1 S3 Boot Script execution
E2 Video repost
E3 OS S3 wake vector call
60 DXE Core is started
61 NVRAM initialization
62 Installation of the South Bridge Runtime Services
63 CPU DXE initialization is started
68 PCI host bridge initialization
69 North Bridge DXE initialization is started
Motherboard Manual
46
Code Description
6A North Bridge DXE SMM initialization is started
70 South Bridge DXE initialization is started
71 South Bridge DXE SMM initialization is started
72 South Bridge devices initialization
78 South Bridge DXE Initialization (South Bridge module specific)
79 ACPI module initialization
90 Boot Device Selection (BDS) phase is started
91 Driver connecting is started
92 PCI Bus initialization is started
93 PCI Bus Hot Plug Controller Initialization
94 PCI Bus Enumeration
95 PCI Bus Request Resources
96 PCI Bus Assign Resources
97 Console Output devices connect
98 Console input devices connect
99 Super IO Initialization
9A USB initialization is started
9B USB Reset
9C USB Detect
9D USB Enable
A0 IDE initialization is started
A1 IDE Reset
A2 IDE Detect
A3 IDE Enable
A4 SCSI initialization is started
A5 SCSI Reset
A6 SCSI Detect
A7 SCSI Enable
A8 Setup Verifying Password
A9 Start of Setup
AB Setup Input Wait
AD Ready To Boot event
AE Legacy Boot event
AF Exit Boot Services event
B0 Runtime Set Virtual Address MAP Begin
B1 Runtime Set Virtual Address MAP End
B2 Legacy Option ROM Initialization
B3 System Reset
B4 USB hot plug
B5 PCI bus hot plug
B6 Clean-up of NVRAM
B7 Configuration Reset (reset of NVRAM settings)
 
Last edited:
Of course I've looked, that was the first thing I did, lol! It's not in there and I can't find anything online.

How come you think an enumerator problem? Never heard of that before.

I reported the issue to Biostar and they sent me the RMA form without any other information. I assume they know of it being a problem?
 
Once the C5 error is up and the fans are spinning but no post, I can hold the power button till it turns off, then press it again and won't get any error on the display but the fans will spin and lights are on. No post then either. Requires the CMOS jumper reset.

When I say display I mean on the Mobo itself...it has a 2 char digital thingy.
 
seems strange that biostar would give you the awesome post code readout then drop the ball and fail to include a post code chart ANYWHERE. its nowhere to be found... thought id found it but the link was dead
 
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