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krasilnik's avatar
krasilnik
New Contributor
6 years ago

Intermittent Service Drops related to Upstream Power Level surges

MODEM Motorola MB7420
Router TPLink AC1900 (although issues occur with or without router in the chain)

I'm looking for some guidance on my intermittent service drops. I have been having this issue since Saturday, May 12th. I contacted support on that day because the Cox website was saying that my account was inactive. I had service at that time and was unaware of any service drops occurring before May 12th.

I was told my account was showing inactive due to a work order that was never closed (from 8 months prior when I upgraded my service speed.) Upon closing the work order, I lost service completely. I was unable to get support to fix the problem, and so they sent a tech to my house the next day.

The tech who showed up determined that my modem entered self registration mode and was stuck there. He had it removed from self registration mode, which reconnected service. He then told me he would need to inspect the wires on the side of my house, and that he would only need to disconnect service if he saw a problem.

Tech goes out, comes back to my door and tells me that he needs to run a test and cut the connection. Did so, came back a few minutes later and said everything was fine. A few minutes later, he left as it appeared service was restored with no issue.

A few hours later, I sat down to do some internetting to find that my service was out. I contacted support again, went through the standard song and dance (check connections, restart modem, etc.) but were unable to locate a specific problem. At that point the agent said he would schedule a supervisor tech to come out.

2 days later (Tuesday, May 15th) another tech comes out. I'm pretty sure she wasn't a supervisor, but I could be wrong. She starts by pulling the coax from my modem, clipping the end and installing a new fitting, then plugs it into her machine. Aside from her seeing "low" upstream power readings (39-41dbmv), she isn't able to find a specific problem. She went outside to look at the wires on my house, doesn't find anything there either. In the end, she put an attenuator on the coax in my house and left.

She left at about 11. My next service outage occurred and 12:40PM, and it's then that I started taking notes. I wasn't sure what I should be noting, so on this drop I didn't get power readings.
Next drop at 6:26PM. Upstream power readings for my four channels were 54.0, 54.0, 43.7, and 54.0. Power cycled the modem and service restored. Power readings dropped into the 43-43 range.

Since then, the pattern has been the same. Drops are intermittent. Each time service drops, power readings spike on 3, if not all 4 upstream channels. Sometimes a power cycle will restore service for the next few hours. Sometimes power cycling does nothing.

Here's a copy and paste of the error logs from the last bit:
Time Priority Description
Time Not Established Critical (3) Unicast Ranging Received Abort Response - Re-initializing MA...
Time Not Established Critical (3) Started Unicast Maintenance Ranging - No Response received -...
Wed May 16 18:43:18 2018 Critical (3) Started Unicast Maintenance Ranging - No Response received -...
Time Not Established Critical (3) No Ranging Response received - T3 time-out;CM-MAC=REMOVED...
Time Not Established Critical (3) Started Unicast Maintenance Ranging - No Response received -...
Time Not Established Notice (6) Honoring MDD; IP provisioning mode = IPv4
Wed May 16 19:23:01 2018 Warning (5) DHCP WARNING - Non-critical field invalid in response ;CM-MA...
Wed May 16 19:23:02 2018 Notice (6) TLV-11 - unrecognized OID;CM-MAC=REMOVED;CMTS-MAC=...
Thu May 17 01:38:03 2018 Critical (3) Started Unicast Maintenance Ranging - No Response received -...
Thu May 17 01:40:13 2018 Critical (3) Received Response to Broadcast Maintenance Request, But no U...
Thu May 17 01:40:34 2018 Critical (3) No Ranging Response received - T3 time-out;CM-MAC=00:40:36:3...
Thu May 17 01:40:44 2018 Notice (6) Honoring MDD; IP provisioning mode = IPv4
Thu May 17 01:40:44 2018 Warning (5) DHCP WARNING - Non-critical field invalid in response ;CM-MA...
Thu May 17 01:40:44 2018 Notice (6) TLV-11 - unrecognized OID;CM-MAC=REMOVED;CMTS-MAC=...
Thu May 17 09:02:43 2018 Critical (3) Started Unicast Maintenance Ranging - No Response received -...
Thu May 17 09:04:53 2018 Critical (3) Received Response to Broadcast Maintenance Request, But no U...
Thu May 17 09:05:05 2018 Notice (6) Honoring MDD; IP provisioning mode = IPv4
Thu May 17 09:05:04 2018 Warning (5) DHCP WARNING - Non-critical field invalid in response ;CM-MA...
Thu May 17 09:05:05 2018 Notice (6) TLV-11 - unrecognized OID;CM-MAC=REMOVED;CMTS-MAC=...
Thu May 17 09:22:54 2018 Critical (3) Started Unicast Maintenance Ranging - No Response received -...
Thu May 17 09:22:54 2018 Critical (3) Unicast Maintenance Ranging attempted - No response - Retrie...
Thu May 17 09:22:54 2018 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream...
Thu May 17 09:23:24 2018 Critical (3) Started Unicast Maintenance Ranging - No Response received -...
Thu May 17 09:23:24 2018 Critical (3) Unicast Maintenance Ranging attempted - No response - Retrie...
Thu May 17 09:23:24 2018 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream...
Thu May 17 09:23:39 2018 Critical (3) Started Unicast Maintenance Ranging - No Response received -...
Thu May 17 09:23:39 2018 Critical (3) Unicast Maintenance Ranging attempted - No response - Retrie...
Thu May 17 09:23:39 2018 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream...
Thu May 17 09:33:37 2018 Critical (3) Started Unicast Maintenance Ranging - No Response received -...
Thu May 17 09:33:37 2018 Critical (3) Unicast Maintenance Ranging attempted - No response - Retrie...
Thu May 17 09:33:37 2018 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream...
Thu May 17 09:58:21 2018 Critical (3) Started Unicast Maintenance Ranging - No Response received -...
Thu May 17 09:58:21 2018 Critical (3) Unicast Maintenance Ranging attempted - No response - Retrie...
Thu May 17 09:58:21 2018 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream...
Thu May 17 10:18:47 2018 Critical (3) Started Unicast Maintenance Ranging - No Response received -...
Thu May 17 10:18:47 2018 Critical (3) Unicast Maintenance Ranging attempted - No response - Retrie...
Thu May 17 10:18:47 2018 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream...
Thu May 17 10:27:00 2018 Critical (3) Started Unicast Maintenance Ranging - No Response received -...
Thu May 17 10:27:00 2018 Critical (3) Unicast Maintenance Ranging attempted - No response - Retrie...
Thu May 17 10:27:00 2018 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream...
Thu May 17 10:27:30 2018 Critical (3) Started Unicast Maintenance Ranging - No Response received -...
Thu May 17 10:27:30 2018 Critical (3) Unicast Maintenance Ranging attempted - No response - Retrie...
Thu May 17 10:27:30 2018 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream...
Thu May 17 10:55:19 2018 Critical (3) Started Unicast Maintenance Ranging - No Response received -...
Thu May 17 10:55:19 2018 Critical (3) Unicast Maintenance Ranging attempted - No response - Retrie...
Thu May 17 10:55:19 2018 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream...
Thu May 17 10:55:49 2018 Critical (3) Started Unicast Maintenance Ranging - No Response received -...
Thu May 17 10:55:49 2018 Critical (3) Unicast Maintenance Ranging attempted - No response - Retrie...
Thu May 17 10:55:49 2018 Critical (3) 16 consecutive T3 timeouts while trying to range on upstream...
Thu May 17 11:00:18 2018 Critical (3) Started Unicast Maintenance Ranging - No Response received -...
Thu May 17 11:02:34 2018 Warning (5) Dynamic Range Window violation

and here's what my upstream bonded channels look like right now, while the connection is active:

   Upstream Bonded Channels  
  
   Channel Lock Status Channel Type Channel ID Symb. Rate (Ksym/sec) Freq. (MHz) Pwr (dBmV)
1 Locked ATDMA 4 2560 18.4 43.0
2 Locked ATDMA 1 5120 36.3 45.0
3 Locked ATDMA 2 5120 29.8 44.5
4 Locked ATDMA 3 5120 23.3 43.5

My modem is 2 years old and I have no reason to believe that it is the cause of the issues.

I'm not really sure what my next course of action should be, and I don't have any faith that another tech will be able to solve the problem without me telling them EXACTLY what needs to be done. Any help here would be greatly appreciated.

krasilnik

1 Reply

  • MarkM1's avatar
    MarkM1
    Former Moderator
    krasilnik,

    I would like to check your equipment as well to see what may be causing the issue with your service. Would you send us an email to cox.help@cox.com with your name & full address so we can check into this for you?

    Mark M.
    Cox Support Forums Moderator