Unresponsive ISY-994 Pro IR ZW

[elvisimprsntr]

I’ve had my ISY99 then ISY994 in service for more than a decade connected to a serial 2412S Insteon PLM. The ISY is powered by the PLM.
 
Except for Insteon in wall and plug in module high failure rates , the ISY and PLM duo have been seemingly rock solid until recently.
 
In the past weeks the ISY randomly stops responding and the activity lights are off even when the power light is on. When I disconnect and reconnect power it starts working again for a few days. I don’t think it’s due to a power glitch on my mains since I get instant notification from my UPS when a glitch occurs.
 
Many moons ago, I bought a second hand ISY-994 with a ZW 500 module, since those were no longer available for purchase, so I could upgrade to the latest firmware.
 
I know UDI no longer provides support for the ISY, but I am not ready to migrate to the eISY. I just don’t have the desire or bandwidth.
 
I was wondering if someone else has experienced similar symptoms and/or what they did to resolve it, or any suggestions. I did make a recent backup of my ISY config JIC.
 
1. Is the SD card going bad? If so how can I replace?
 
2. Is the PLM suspect?
 
3. Is the ISY itself going bad? My recollection is the second hand ISY I purchased does not have all the module licenses activated. I recall at one time UDI would migrate licenses to a different device for a small fee. Not sure if that is an option anymore.

[DennisC]

Have you tried a new power supply? 

Just because the light is on doesn't mean it meets specs and failed power supplies are somewhat common.

[elvisimprsntr]

Have you tried a new power supply? 
Just because the light is on doesn't mean it meets specs and failed power supplies are somewhat common.

It’s powered by the PLM.

[DennisC]

Just now, elvisimprsntr said:

It’s powered by the PLM.

Sorry, I missed that. It's possible the PLM is failing.

[Brian H]

If it is powered by the PLM. You are still using a power line only 2412S PLM? As the Dual Band 2413S PLM does not power the ISY99i or ISY994i.

I would suspect the 2412S PLM has finally started to fail. Or since it is power line only. Something has changed and now you have power line noise or a signal sucker.