I am having the same exact problem. Have been for a couple of months now. Every single connection, cable, and splitter has been changed, and I've had three different modems. Also have tried this on three different computers. The send and receive lights will go solid, but the cable/online light will not. This happens whenever it feels like it, and I haven't been able to notice a pattern yet. I have had one tech say that the amplifier box down the street is the problem, but I can't seem to get them to fix it, and another guy said it is probably my ground wire. Have you found the answer to YOUR problem yet?
After several years of perfect service, my cable modem started intermittent (up to 12 times a day) recycling (all lights go out and it reconnects) 2 weeks ago. These 2 error msgs ALWAYS appear in the cable modem log when this happens:
2006-04-07 20:12:14 3-Critical R004.0 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received. T4 timeout.
2006-04-07 20:11:42 3-Critical R005.0 Started Unicast Maintenance Ranging - No Response received - T3 time-out
On 4 visits, 5 technicians from the cable company have replaced the modem and power supply, put new connectors on all cables, replaced the splitter, checked the cables leading to the street, and boosted the signal power coming into the house. The upstream/downstream signal and cables are fine. The recycling occurs whether I am on the internet or not and whether my computer is turned on or not. The computer, modem, and cables have been in the same place for a year and a half - no new hardware or changes.
Is the anyone familiar with these error msgs or this problem? Thank you.