EG,
Would you mind answering a couple of questions for me? I'm having similar problems to the OP. I have a motorola surfboard 6121 modem in a configuration that was installed by a Comcast Tech. I think it's split 1 extra time but right now I can't help that without tearing into a wall and that isn't a step I really want to take unless absolutely necessary. It was wonderfully stable and worked perfectly for months until recently, which is what I don't understand. Now it drops and resets far more often than I would like.
Configuration:
Line into condo---->splitter (may be older one, not sure, this one is in a wall) -----> amplifier/splitter -----> cable modem.
Basic numbers:
Downstream SNR: 35 on 3 channels, 34 on 1.
Downstream power levels: -7, -4, -8, -5
Upstream Power level: 56dBmv
Screenshot signal page: http://gyazo.com/8df65f241da81756b6216c4a01261786
Screnshot log page: http://gyazo.com/5e7b427abf79ef3ca8178aa6ee870b09
Speedtest: http://www.speedtest.net/result/3363163916.png
I have the Extreme service. The speed tests vary quite a bit... in the last three I did I had one d/l around 50, one around 90, and 1 around 100. The upload is always more stable.
Anyway, are the levels out of spec or close? Again, until recently the modem has been very stable in the same configuration. I could open up the wall where the first splitter is and replace it but I can't remove it without killing the TV in several other rooms. It isn't possible to put the cable modem there.
Any help much appreciated. I'd love to know what the acceptable ranges are for all of the upstream and downstream numbers too.