So today I decided to pull out my old 2.4 PLM that I haven't used in years and recap it. I removed the first two 50v 100 μF caps and tested them with my ESR tester. They were right on spec and ESR was 199 to 220 mΩ. The replacements are like 350 mΩ which is fine but the point is these aren't failing. I tested the remaining caps while still installed and they are all good. I should have checked before wasting time replacing caps that were actually fine. So the random memory loss resulting in the PLM links table clearing out does not appear to be because of bad caps.

Thank you for the information.

We have seen other posts indicating caps didn't always correct things.

2.4 should have the updated serial port daughter board with the better serial interface chip and a surge protection network on the serial signals to the outside world. Along with the better caps.

The 2413S serial PLM is now discontinued on the Insteon sales site.

Edited Friday at 01:20 PM4 days by Brian H
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14 hours ago, sorka said:

So the random memory loss resulting in the PLM links table clearing out does not appear to be because of bad caps.

Failure of the EEprom to retain link values can be caused many things other than bad caps. Bad caps is just one possible cause. Historically EEproms have been susceptible to corruption from abrupt power supply changes and bad caps can cause that to happen, but are not the only cause.

Yes you should have checked before replacing the caps.

The first step in diagnosing possible cap issues would be to measure the 20V supply voltage, not pulling them out and measuring ESR.

For $1, I simply replaced all the caps in my PLM. Then, drilled a lot of holes in the case for airflow to keep it cool.

That was over a decade ago. I am glad I simply replaced everything for so little $$$, and didn't overthink it.