Maybe, maybe not. A malfunctioning adapter could hobble the whole network. That said, you could try each adapter with the other powered-off; each adapter should be able to link with the MoCA-enabled gateway.
A couple other simple tests you could try…
- direct-connect the Actiontec ECB2500C adapters to each other using a short coax cable and verify coax/MoCA status LED lights up. Optionally connect one of the adapters via Ethernet to the router LAN and the other to a computer and test connectivity and throughput.
- similarly, but less direct… insert a 2-way splitter in front of the MoCA-enabled gateway, connecting the splitter input to the room’s coax outlet and the gateway to one of the output ports. Then try each of the ECB2500C adapters on the other output port to test that each can connect.
If the adapters link in both scenarios above but not when installed in their original location, it would point to the tech having done more than simply plugging your distribution amplifier’s power source back in.
Can you provide model # info for the power adapter and its amplifier? Can you post a pic of the amplifier and the connected coax lines?