Question No BIOS Access with DEL key

[LOHPLT]

OK8. Short description is no BIOS access on reboot.

Mobo: ASUS Maximus IV GENE Z/GEN 3
CPU: Intel I7 Sandy Bridge
Drive 0: SAMSUNG 1 TB SSD (WINDOW 10)
Drive 1: SAMSUNG 1 TB SSD (User Data)
Display output supplied by the IGPU.
Standard 101 key generic USB keyboard.

I’ve built several computers over the years and had good success. This MOBO has been relatively good...no problems of any note. The current setup scores about the 85th percentile with PASSMARK. I troubleshot many issues over the years, but this one is a little weird. I can not access the BIOS on a bootup. It just takes the following sequence:

ASUS BIOS screen for about 2 secs > black screen for about 1 sec. > back to the BIOS screen waiting for the DEL key input. I have tried 2 different keyboards and all of the USB inputs. The keyboards light up, but pressing the DEL does nothing. It just sits at the BIOS screen.

Ok fine, I’ve had a few self-induced BIOS issues in the past. OK...so I’ll just reset the BIOS. So, I follow the normal procedure of moving the CLRTC_SWC jumper from Enabled (Default pins 1&2) to Disable (pins 2&3) for 10 secs and reboot. Again, no response to DEL key.

Ok. Now repeat above proc again, but remove the CMOS battery as well. I left it jumpered and battery out overnight just to be sure the EPROM clears.

Next morning I moved the jumper back and replaced the battery, and also checked the battery voltage at 3.3 VDC - looks good. Reboot it and it is the same result; no response to any keyboard input. I tried different keyboards and different USB ports and got nothing.

The 2-digit DEBUG LED finishes with “A2” = “IDE Detect”.
The Q-LED “BOOT_DEVICE_LED” is ON (illuminated).
The display (IGPU) is again stuck at the BIOS screen and requests “Please press DEL to enter EFI BIOS setting”.

The only thing left is a suspicion that the BIOS may not respond to the USB keyboard, but might respond to a keyboard plugged into the PS/2 keyboard input. It’s just a weak hunch, but it’s all I can think of right now. I am at a loss for further t’shooting ideas. I am waiting on delivery of a USB-to-Pa
S/2 mouse/keyboard adapter.

There is a collateral question. What’s the purpose of the “CMOS Reset” button on the rear of the mobo? If one can reset the BIOS using a “CMOS Reset” button on the rear edge, why the need to jumper the CLRTC_SWC header?

 

[RARRAF]

as you said the PS/2 keyboard input is the only thing really hope it works.

 

[LOHPLT]

Ok. Update; no joy with PS/2 connection. I really didn't think it would matter, but hey you gotta try. I've never had anything like this occur in my experiences. I've ALWAYS been able to access at least the BIOS. The only other clue is that the rear two USB 2.0 ports appear dead. USB ports #1 and #2 don't light up the USB keyboard; all the other USB 2.0/3.0 ports "appear" active, or at least they are supplying 5.0 VDC to the keyboard lights. Maybe that'll offer someone a clue. It's got me baffled.

I built this computer from scratch 8+ years ago and it's always been solid performer. No serious gripes until now. I've removed the graphics card and disconnected the SATA drives. So it's pretty much just raw now. I can always salvage the most of components, although most of the major items are a little dated. Maybe a used mobo suitable for CPU could yield a reasonable standby computer. I wish could nail down the problem a little finer before I go chasing a mobo replacement. Thanks for the reply; much appreciated.

 

[LOHPLT]

Follow and Closed: I found the problem. One of the integrated USB ports was broken. Broken in the sense that the USB Type A female connector had lost/damaged the thin plastic tab that supports the four very small copper connectors. The plastic tab had become damaged and cracked, and evidently fallen out or the USB receptacle. One of the copper connected had been bent until it touched the receptacle wall. This effectively grounded the one of the connectors. This was enough to prevent even the BIOS from booting. Learning point: check your hardware; especially the external connectors.