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SLC 5/04 Lights are flashing in RUN Mode

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I have a friend of mine that just called me from CA. All the lights on the SLC 5/04 are flashing around like the CPU is in infinite reset. They are out in field and dont have the laptop with them When they put the processor in PROGRAM it stops cycling the lights and appears to act ok, Once he puts it back in RUN mode, ALL the lights are flashing Any ideas? Thanks

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Obviously that's not normal. If they can make some notes about which LEDs, what color they are flashing, and in what sequence, that might help characterize precisely what is going on inside the controller. All indications point to a failed controller, though. I've seen LED patterns I don't recognize when an OS update failed, and I've seen them when a DH+ daughtercard failed. Regardless of the reason, the likely solution is replacement of the controller.

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Thanks Ken, It appears that It's repeating the start up sequence over and over. I suggested cycling power. verifiy the battery Do a upload and go online to verify any possible errors, but usually in my experience you will get a FAULT on the CPU if thats the case. I think they are going to try to wipe the processor (VBB /GRD) and try to re-download. If that doesnt work then it's more than likely the SLC is faulty. The processor is quite old, so maybe its time. I'll post what they find I'm presently in Maryland tryin to help a California bud Thanks again Ken

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Do you think it could be "Fault ..Fault routine... Reset... Fault... Fault routine...Reset..."?

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Could it be a power supply problem? Maybe a shorted input or an output, pulling the supply down to a point that shuts it down?

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The decision was made to replace the SLC 5/04 because of its age. They downloaded the RSLogix file, and everything appears to be ok. Edited by ICTechs.com

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Well the demon came back, and I suggested checking the power supply, and indeed it was the power supply. The power drop was enough to cause the SLC to go into infinite cycling of start-up reset. They replaced the power supply, problem solved mracer called it first Edited by ICTechs.com

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Have the same problem , SLC5/04 CPU , all CPU leds bling in a sequence in a loop , but here is worth , this company I a servicing , cant find the program backups , so if the PLC is not back for an upload then maybe a new program from scratch on a new PLC will have to be done. I am attaching a small video of the leds sequence  

VID_20210701_150227.mp4

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replacing the power supply didn't help

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According to the troubleshooting section of the user manual, the processors DH+ connection is faulted (duplicate note, perhaps) or failed, or the processor itself has failed.  The RS232 light being OFF is the critical difference between blown memory and blown processor.  I recommend your client make a closer search for the backup files. ):

https://literature.rockwellautomation.com/idc/groups/literature/documents/um/1747-um011_-en-p.pdf

One last hope:  try using the serial port with DH+ disconnected.

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