OK, Got my package today containing 2 more XPPF 5 amp filters. As suggested, I put 2 in series, then the Microwave.
No luck The X-10 in 2 rooms still does not respond.
My next attempt will be a AF-120 15 amp filter unless someone tells me that 3 XPPF 5 amp filters in series is the trick. Then I will disconnect one of my other ones and try 3. They are a pain to put in series however.
I am adding this after the fact. Per the owners manual, the power requirement for the microwave is: "A 120 Volt, 60 Hz, AC only, 15- or 20-amp electrical supply with a fuse or circuit breaker."
Based on that, I think I need a 15 amp filter. Thoughts???