I have a strange issue, and I am hoping I can get some input. The modem will always keep a connection for several days (I have the SB6183) but then the signal will slowly degrade and accumulate a large amount of uncorrectables. Also, the power levels on the downstream channels goes down by several dBmV (from 2 or 3 down to 0) and the upstream will go up by several dBmV (from 44 or 45 to 47 or 48). I have some screenshots but I don't know how to post them.
The only thing that seems to resolve the issue is to remove the coaxial cable from the back of the modem for several seconds and plug it back in. After that the signal levels are normal and I have no issues for several days, until I have to repeat the procedure.
I live in an apartment building. I've had technicians come out here but no one seems to know what the issue is, and usually when they come out, they disconnect and reconnect something, and natually that resolves the issue while they are here until it crops up again later after they've left.
Have they put new connectors on everything?
Is there a splitter or connector behind the wall plate?
If not, there's a splice somewhere in the building that's bad.
Good luck getting it fixed
I don't know a lot about the connections in the building, but from the line that comes into the apartment there is one splitter (-3.5, -3.5), and the cable modem runs off a direct line from there. It's not a very long run and the cable is relatively new, the connectors seems to be ok, and all the connections are tight. There are no unterminated connectors, no amplifiers or other devices on the line, and I cleaned the copper at every point with rubbing alcohol and let them dry, but it doesn't seem to resolve anything. I still have the same issues.
Check the system grounding. Be sure the ground is continuous from the entrance to the modem - no connector shells broken loose from the sheilds. It's possible to get a static voltage build up on the cable and that affects the modem.
What does the other port of the splitter feed?
Alcohol won't fix a bad connection. Is the center wire shiny copper or dull or corroded?
The other end of the splitter goes to another splitter, and from there to two cable boxes. All the connectors look shiny, so I don't think that's the issue. I was thinking it could be noise ingress or static, but I have no tools to check or verify either one, and about grounding I am not sure what to look for. The cable comes into the apartment, to the splitter and from there to the modem in one single cable run. All the connectors are intact (no breaks or cracks). Is there anything I can do on my own or am I only limited to having a tech come out and tell me that everything is working fine?
I'm sorry. I've been a little busy and I didn't have a lot of time to reply.
The cable TV is working fine. I never see any issues or dropouts in the service. This is a list of items in the log that I can see since the last time I rebooted it (I removed some of the MAC details):
|Mon Mar 16 09:54:21 2015||Notice (6)||DHCP Renew - lease parameters Time Protocol Servers modified;|
|Mon Mar 16 09:54:21 2015||Error (4)||DHCP RENEW WARNING - Field invalid in response v4 option;|
|Sun Mar 15 14:14:54 2015||Critical (3)||Started Unicast Maintenance Ranging - No Response received - T3 time-out;|
|Thu Mar 12 21:54:18 2015||Notice (6)||DHCP Renew - lease parameters Time Protocol Servers modified;|
|Thu Mar 12 21:54:18 2015||Error (4)||DHCP RENEW WARNING - Field invalid in response v4 option;|
|Wed Mar 11 21:03:16 2015||Critical (3)||Started Unicast Maintenance Ranging - No Response received - T3 time-out;|
|Tue Mar 10 18:16:54 2015||Notice (6)||TLV-11 - unrecognized OID;|
|Tue Mar 10 18:16:54 2015||Error (4)||Missing BP Configuration Setting TLV Type: 17.9;|
|Tue Mar 10 18:16:54 2015||Error (4)||Missing BP Configuration Setting TLV Type: 17.8;|
The modem hasn't rebooted yet, but I see the signal degrading again:
|Channel||Lock Status||Modulation||Channel ID||Frequency||Power||SNR||Corrected||Uncorrectables|
|1||Locked||QAM256||16||369000000 Hz||0.8 dBmV||40.4 dB||265||38|
|2||Locked||QAM256||2||285000000 Hz||1.0 dBmV||40.3 dB||453||81|
|3||Locked||QAM256||3||291000000 Hz||1.0 dBmV||40.3 dB||398||83|
|4||Locked||QAM256||4||297000000 Hz||1.0 dBmV||40.5 dB||316||90|
|5||Locked||QAM256||5||303000000 Hz||1.0 dBmV||40.5 dB||337||46|
|6||Locked||QAM256||6||309000000 Hz||0.7 dBmV||40.3 dB||367||84|
|7||Locked||QAM256||7||315000000 Hz||0.8 dBmV||40.4 dB||330||69|
|8||Locked||QAM256||8||321000000 Hz||0.7 dBmV||40.3 dB||358||39|
|9||Locked||QAM256||9||327000000 Hz||0.9 dBmV||40.4 dB||335||69|
|10||Locked||QAM256||10||333000000 Hz||0.9 dBmV||40.5 dB||310||47|
|11||Locked||QAM256||11||339000000 Hz||0.6 dBmV||40.2 dB||312||56|
|12||Locked||QAM256||12||345000000 Hz||0.9 dBmV||40.3 dB||316||54|
|13||Locked||QAM256||13||351000000 Hz||1.1 dBmV||40.5 dB||276||121|
|14||Locked||QAM256||14||357000000 Hz||0.9 dBmV||40.4 dB||283||45|
|15||Locked||QAM256||15||363000000 Hz||0.7 dBmV||40.3 dB||274||43|
|16||Locked||QAM256||1||279000000 Hz||1.4 dBmV||40.6 dB||393||99|
|Channel||Lock Status||US Channel Type||Channel ID||Symbol Rate||Frequency||Power|
|1||Locked||ATDMA||4||2560 Ksym/sec||37000000 Hz||48.0 dBmV|
|2||Locked||ATDMA||2||5120 Ksym/sec||24200000 Hz||46.5 dBmV|
|3||Locked||ATDMA||3||5120 Ksym/sec||30600000 Hz||47.0 dBmV|
|4||Locked||TDMA||1||2560 Ksym/sec||19400000 Hz||46.5 dBmV|