KR15 with KRC2 not starting

    Hello,

    At the university I'm responsible for a KR15 robot with a KRC2 controller. Since last friday, the controller won't boot. The cabinet fan turns on, the 24V rail is present, also at the input of the power supply of the PC, yet the PC refuses to start.

    Where and how to start debugging? In the documentation of the KRC2 I found something about some status LED's on the upper right unit in the controller cabinet. yet it's unclear what the current status is trying to tell. LED 1 (Red) is off, LED2 (green) is blinking at 1Hz.

    Also the status leds on the motor drives are blinking (red LED burns continuously, green LED linking at 0.5Hz approx.)

    Thanks

  • Go to Best Answer
    Quote from Jones1403

    Hello,

    At the university I'm responsible for a KR15 robot with a KRC2 controller. Since last friday, the controller won't boot. The cabinet fan turns on, the 24V rail is present, also at the input of the power supply of the PC, yet the PC refuses to start.

    Where and how to start debugging? In the documentation of the KRC2 I found something about some status LED's on the upper right unit in the controller cabinet. yet it's unclear what the current status is trying to tell. LED 1 (Red) is off, LED2 (green) is blinking at 1Hz.

    Also the status leds on the motor drives are blinking (red LED burns continuously, green LED linking at 0.5Hz approx.)

    Thanks

    Hello, does the PC fan turns on also? Is there any picture on the KUKA pendant(KCP)?

    perhaps the PC boots but the KCP backlight is gone...

    i would start by checking it the KPC get 24VDC, does the PC PSU turn on? if so PSU output connectors wil have 5V on red wires and 12V or so on yellow wires (black wires are 0VDC).

    1) read pinned topic: READ FIRST...

    2) if you have an issue with robot, post question in the correct forum section... do NOT contact me directly

    3) read 1 and 2

    • Best Answer

    It should be possible to connect a VGA monitor directly to the KPC. If the issue is in the pendant, the monitor should still show an image. KRC2 pendants have flourescent backlights that can burn out, leaving the LCD so dark that it looks non-functional, but if you look very closely, you can still see the pixels in operation.

    Another test is to simply hit the open/close on the CD-ROM drive and see if the drive cycles. If not, that suggests that the AT (ATX?) power supply in the KPC is not putting out any power. And of course, checking the power on the hard drive cables as Panic suggests is another item. The KPC is basically a regular PC in hardware terms, aside from the MFC card and the very tight specs (like RAM timing).

    When main power is applied, watch the indicator lights on the CD-ROM and floppy drives. They should show brief activity as part of the BIOS checking for boot media.

    If you don't have a full image backup of the HDD, it might be a good idea to yank the HDD and back it up on a PC using Acronis, CloneZilla, or something similar. Before trying to run anything like CHKDSK on it. Although if you're not even seeing BIOS POST at the start of boot, the HDD probably isn't the problem, but on KRC2s, HDD corruption is always lurking these days.

    Possibly the CMOS battery on the motherboard died?

  • Jones1403 March 13, 2025 at 8:33 AM

    Selected a post as the best answer.
    Quote from hermann

    When this happened, the main board doesn't start itself with power on. One must power on by connecting pin PS_ON (green) and GND(black) for a short time.

    Thank you all for the valuable contributions.

    Indeed the CMOS battery on the KPC motherboard died. The KPC was not booting at all. No Fan, no power to the CDROM,...

    I replaced the CMOS battery and jump started the ATX PSU as per directions from Hermann.

    The KPC booted right up after pressing F1 to re-initialise the BIOS settings.

    Thanks again, I'm glad this forum exists!

    Quote from Jones1403

    Thank you all for the valuable contributions.

    Indeed the CMOS battery on the KPC motherboard died. The KPC was not booting at all. No Fan, no power to the CDROM,...

    I replaced the CMOS battery and jump started the ATX PSU as per directions from Hermann.

    The KPC booted right up after pressing F1 to re-initialise the BIOS settings.

    Thanks again, I'm glad this forum exists!

    If you needed to replace CMOS battery, the BIOS setting also got reset and maybe now everytime you shutdown the controller you will need to jumper the PWR_ON pins on the motherboard until you restore KUKA bios setting in BIOS.

    Just ran into a possibly-related case myself. An ed2005 KRC that when rebooted threw a CMOS CheckSum Error during the BIOS post, before starting Windows. Plugging in a keyboard and hitting the Continue option let the robot complete boot (hibernation recovery), with no other apparent issues.

    Which leaves me wondering: is this indicative of the CMOS battery going, or could it be a warning sign that the CMOS memory is starting to fail?

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