CompactLogix L18 losing program

[rcflyer91]

Have you tested/Replaced the on-board battery?

 

[phuz]

No, I didn't know this was a possibility. I actually thought they were soldered capacitors these days.

 

[VAN]

You try using a memory card yet? Not that it would prevent the fault but on power up should be able to set it to download the program.

 

[kellian]

Check all Earth connections. I have seen similar symptons on a SLC.
we reterminated, cleaned, tightened all Earth connections related to the processor.

 

[Ken Roach]

If *all* of the LEDs are off, then the controller's power supply has gone into a shutdown mode. Like many power supplies, it will do that to protect itself; it's called a "crowbar" function.

And please remember that this controller was purchased off eBay, and has been known to be defective from Day 1. It was probably sold to phuz cheaply by somebody who rescued it from a trash bin.

He could go after this with a freeze-spray can, or a heat gun, or a vibration device to try to shake the culprit component loose. If this was a QC lab or a forensics investigation, that might be worth doing.

But in practice, this is a defective power supply, and there's nothing he can do from the outside, or in software, about it.

 

[phuz]

Test bench it is.