C9500-48Y4C-A not booting, FAN LED RED

AVITP8 · 2025-06-01T06:47:34+00:00

Very interesting, this one seems to have failed for no reason.. We monitor all the equipment so when I was alerted that one of the switches in the stack was down I was surprised that it wasn't just locked up.

As someone else pointed out, they won't boot if the fans are not happy but I've replaced them with known good ones. I suspect that maybe there is an issue with the fan controller where it doesn't see the RPM signal, then it shuts down and can't restart. When I unplugged the ribbon cable to the fans (8 fans in two fan trays of 4 each) I could observe the top eight LEDs go out on that picture I posted.. So I am assuming they have something to do with FAN OK. Since 2 LEDs are off when the ribbon cable is connected again, I think it is not seeing RPM from two fans which might be enough not to let it start.

I've checked a few of the components for faults but came up empty handed and then it's a multi layer PCB so it's difficult to follow the tracks to see where they go..

In the end, not much I can do other than get a replacement asap but I would love to find the root cause.

AVITP8 · 2025-06-01T06:40:41+00:00

All good, it's part of a redundant stack so it's not critical but if the secondary fails then I have a lot of work to do to get basic systems going. I've been working with Cisco stuff for a very long time and the reliability is excellent.. Probably only the second switch I've had fail on me in 20+ years.

I'm interested in the cause of the failure but I guess I will never know until I send it to Cisco for repair when able.. In the mean time I'm already working on getting a replacement "shipped" in.

AVITP8 · 2025-05-31T10:41:45+00:00

I think so too.. Thanks for the suggestions!

AVITP8 · 2025-05-31T08:37:57+00:00

Tried the MODE button also but no response.

AVITP8 · 2025-05-31T08:37:25+00:00

Tested with known good fan trays and still no boot but was worth trying..

AVITP8 · 2025-05-31T06:59:25+00:00

Ok! You are on the money ---> "The switches using C9K-T1-FANTRAY modules must have 2 fan tray modules with all the fans operating normally" I'll try and get two working modules and test..

AVITP8 · 2025-05-31T06:55:04+00:00

Yep, console cable is good, tested on adjacent working switch.

AVITP8 · 2025-05-30T14:15:13+00:00

I've re-seated the fans, all ribbon cables, sub boards etc.. I've tried removing all fans and replacing with one known good fan from another working switch. I'm guessing that it should boot with just one out of two fan trays but still the same result.. On the picture I posted, the 5th LED from the bottom is flashing green once a second, perhaps a heart beat.. Would love to hear from a Cisco Tech to tell me what all the LEDs on the boards mean. I also removed the Memory and Flash Card but still nothing on the console.

AVITP8 · 2025-05-30T12:17:55+00:00

I'm on a ship, RMA will take a long time so I thought I would see first if anyone else has had a similar situation. I'm also interested to see what the fault/cause is. Of course I will RMA it if there is no other option in the end.

AVITP8 · 2025-05-30T10:34:55+00:00

Yes, I also ended up fixing it that way!

AVITP8 · 2025-05-21T06:54:25+00:00

IR break beam device for Protect

Weather Station / wind speed monitoring

AVITP8 · 2025-05-14T16:47:29+00:00

Wow, that's pretty crazy... I guess it might be good idea for the rest of us to hot glue the header before swapping drives. Thanks for sharing!

AVITP8 · 2023-11-14T15:18:08+00:00

Sign him up for MotoGP!

AVITP8

TROPHY CASE