best place to start is looking at signal levels by going into modem gui. 10.0.0.1, 192.168.100.1. etc
The coax line won't have static build up. it is grounded were it enters your house.
the channels it locks onto should be closest to 0 in the dB scale, if your -/+5 dB on the channels it could lead to disconnects or not connecting at all.
"if your -/+5 dB on the channels it could lead to disconnects or not connecting at all. "
The range is -10 to +10
|Downstream Power Level|
|Gateways and EMTAs||-7dBmV||+7dBmV|
|Downstream Signal to Noise Ratio||35dB||-|
|Upstream Power Level||+35dBmV||+50dBmV|
|Upstream Signal to Noise Ratio||31dB||-|
|Upstream Receive Power||-2dBmV||+2dBmV|