The upstream power is too high and may be intermittently fluctuating even higher out of spec.That will cause random disconnects and spontaneous re-booting of the modem. Are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured ?
If there aren't any unneeded splitters that can be eliminated and if your coax wiring setup can't be reconfigured so that there is a single two way splitter connected directly off of the drop from the street/pole with one port feeding the modem and the other port feeding the rest of the house/equipment with additional splits as needed and you've checked all the wiring and fittings for integrity and tightness and refresh them by taking them apart then putting them back together again, then perhaps it's best to book a tech visit to investigate and correct.
The upstream is far better but now the downstream is low but it may work. You need to see if the issue still exists over a period of time. FWIW, excess attenuation affects the up and downstream power levels in the exact opposite way so this is basically a balancing act.
I've been having this problem for about a month and was on the verge of giving up and switching to UVerse until I found out how slow UVerse's upload time is. Where did the "event log" in the first message come from? I tried going to http://192.168.100.1 and clicking on "signal" but got a message saying that this feature was not enabled on my modem. As for the fix given in this thread, I don't even know what a splitter is. Should non-techies not use cable modem. (I used DSL for about fifteen years -- switched to cable less than a year ago because the DSL was too slow. This was before UVerse was available in my neighborhood. It's available now.)
The problem is not with my router. Removing it from the configuration didn't solve the problem. I've also tried repowering everything. The connection is working right now, but at any moment it may go away for a matter of minutes or possibly hours (usually it's less than half an hour, but once it was well over an hour). At that point I will have the choice of using my iPhone (which won't work for everything I need to do online) or hoping that an unlocked signal from around the corner is strong enough to let me do crucial things. I can't live like this much longer.
I can report that my connection hasn't totally crashed in the past two hours. BUT it is taking everything forever to happen. E.g., to come to this page, I had to wait while the "connecting" circle went round and round for about five minutes. Is this some kind of temporary horror, or is it permanent? I am paying for the hightest level offering Comcast has in my area (Jackson, Mississippi). If this is the best, I will be gone by Monday.
My connectivity problems continued to get worse all weekend. Now I'm connected for only a few minutes at a time before being once again disconnected. I put in a UVerse order today but will have to continue living in this Comcast nightmare for a couple of weeks.
I've been trying for the past five hours to upload two pictures. No luck so far. I managed to stay connected to Comcast for fifteen minutes at one point (an unusually long time for the connection not to drop), but the upload of the pictures seemed to be mired in molasses. It timed out -- and timed out -- and timed out -- and timed out. I am paying Comcast for the top level of connectivity for this??
