I have an iSY994y/2413S combo and I have successfully set up a number of other Insteon switches on this setup (2477S, 2466SW, 2334-2).  However, I have a handful of 2476S and 2476D switches, and none of them will pair.  Here is what I tried:

1. Link Management -> Start Linking in the admin console, then hold the Set button for 3 seconds.  The switch never shows up in the console.  The same procedure worked fine for the 2477S.
2. Factory reset the 2476 by holding Set for 10 seconds while applying power.  It doesn't beep and I can't tell if this has an effect.
3. Tools -> Diagnostics -> Event Viewer -> Device Communication Events.  I don't see anything in here regarding the 2476, even if I press/hold the button on it

The 2476D (dimmer) switches buzz for a few seconds right after applying power.  I don't know if this is normal, but every single one of them does it so it would be odd if they all suffered from an identical hardware failure.

The 2476 switches are all able to control the load by pushing the paddle switch.

All devices are on the same AC phase and local to each other.

I don't think the 2466SW is a dual band device so if I was able to successfully pair it, that means that powerline comms are working correctly.
 

How old is the 2476S?

The original 2476S that does not have the Air Gap switch part of the Set Button assembly. Has a different Factory Reset procedure. I can get it for you if needed. If there is no Air Gap switch. Pulling out the Set Button would not turn it Off. If uninstalled you should be able to look through the case and see if there is a switch.

What type load is on the 2476D modules?

Yes they all are single band power line only modules. Not 100% sure if a 2466sw working and the others not. Is a total test. Can you splice one into a power cord and plug it into the same outlet as the PLM as a test?

Edited July 6, 20223 yr by Brian H
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2 hours ago, Brian H said:

How old is the 2476S?

The label on the 2476S says: V2.5 1511

The label on the 2476D says: v5.0 0948

2 hours ago, Brian H said:

If uninstalled you should be able to look through the case and see if there is a switch.

I see a switch -- two copper contacts that open when I pull out the Set button.

2 hours ago, Brian H said:

What type load is on the 2476D modules?

I have tested with an open circuit on the red lead, and with a small light bulb.  The dimming functionality seems to work fine when I use the paddle.  The only problem is that it won't pair with the iSY/2413.  And the weird buzzing on startup.

2 hours ago, Brian H said:

Can you splice one into a power cord and plug it into the same outlet as the PLM as a test?

Yes, that is how I am currently testing them.  Plugged into the same power strip, no surge suppressors.

I have one taken apart (mostly) and I'm debating whether to drill out the rivet.  I could try replacing the caps if I knew which ones to order.  But it is weird that all of these are exhibiting the same behavior, and it's not a failure mode that anyone else on the forums has reported AFAICT.