My ISY will boot only in safe mode - if the PLM is connected it won't let me telnet in. The Rx light on the ISY flashes when there's Insteon traffic - no lights are lit other than the power LED.

What should I do next to troubleshoot this?

I have a very recent backup if necessary

I've tried:

a) using a different (known good) network cable

b) resetting the PLM

No success with either :/

Did you plug the plm into port A and power it up prior to powering up the ISY?

16 minutes ago, lilyoyo1 said:

Did you plug the plm into port A and power it up prior to powering up the ISY?

Just tried that - same result. I can ping the ISY, but not connect to it.

Try factory resetting the plm and plugging it into a different outlet. If that doesn't work then it's bad.

Yes, it looks like a dead PLM. I've ordered another one. Thanks @lilyoyo for confirming my bad news!

If only Insteon's hardware were as reliable as UDI's hardware.

I don't post much, because I have few questions, but I am always amazed by Michel's low latency, high accuracy responses on this forum. UDI's customer support is amazing, and the products are just as good.

If it is less than two years old. Call Smarthome Customer Support and get a warranty exchange.

Make sure you follow the proper procedure to replace the PLM.  https://wiki.universal-devices.com/index.php?title=ISY-99i/ISY-26_INSTEON:File_Menu#Restore_Modem_.28PLM.29

There is a long thread here on the PLM failures and how some of us have rebuilt ours with  good capacitors.  https://forum.universal-devices.com/topic/13866-repair-of-2413s-plm-when-the-power-supply-fails/

When you get your replacement. If you would post the Date Code and Hardware Revision number on the back. It would be nice to know. I have seen a few recent reports of V2.5 hardware being received.

Edited July 23, 20196 yr by Brian H

I got a V2.4 from Amazon - dated 1017.

Disturbingly, the ISY doesn't want to talk to it either.

Any thoughts on what to try next?

What was your step by step process

I followed the instructions from the wiki post referenced above by Brian H.

Since I have a recent backup, I decided to factory reset the ISY and restore from the backup. That seemed to do the trick - it's working fine with the 'old' PLM now. Annoying, as it'd be nice to have had the logs to see if it's something that might happen to other people.

Anyway, I'm back in business...living in a non-smart home for 24 hours wasn't much fun