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Frequent Internet dropouts, all about 2 minutes each.

This problem relates to the connectivity of my Arris SB6141 cable modem and has no relevance to the standalone router home network.  For about the past three weeks, we've had frequent and consistent loss of the Internet for periods of about 2 minutes or less.  During these outages, the cable modem shows only the power LED on, the rest go dark, and then sequentially come back on once connectivity is restored.  Here's a log for outages between July 10 and today, except for a couple of days when we were out of town:

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NetUptime Monitor Failure Log
(NetUptimeMonitor.com)
Licensed to -------------

Failure Start / Length
7/10/2019 1:01:44 PM 0:01:55
7/10/2019 1:33:10 PM 0:02:02
7/10/2019 2:09:28 PM 0:01:56
7/10/2019 2:55:32 PM 0:01:59
7/10/2019 3:09:49 PM 0:00:17
7/10/2019 3:31:24 PM 0:01:52
7/10/2019 8:56:02 PM 0:00:14

7/11/2019 1:42:20 PM 0:02:00
7/11/2019 1:45:26 PM 0:01:57
7/11/2019 8:53:37 PM 0:01:59
7/11/2019 9:22:47 PM 0:02:10

7/12/2019 12:57:41 PM 0:01:56

7/13/2019 3:12:57 PM 0:01:52
7/13/2019 3:30:24 PM 0:02:12
7/13/2019 8:20:57 PM 0:01:53

7/14/2019 11:54:12 AM 0:01:59
7/14/2019 12:53:40 PM 0:01:55
7/14/2019 2:42:10 PM 0:01:57
7/14/2019 2:48:33 PM 0:02:11
7/14/2019 3:17:34 PM 0:01:48
7/14/2019 3:35:40 PM 0:02:14
7/14/2019 7:16:04 PM 0:01:59
7/14/2019 7:25:11 PM 0:01:53
7/14/2019 9:57:13 PM 0:02:03

7/15/2019 3:09:51 PM 0:02:05
7/15/2019 3:18:13 PM 0:02:14
7/15/2019 3:37:54 PM 0:00:46
7/15/2019 7:32:00 PM 0:02:06
7/15/2019 7:42:33 PM 0:02:05
7/15/2019 7:50:50 PM 0:01:57
7/15/2019 8:03:28 PM 0:02:09
7/15/2019 8:14:21 PM 0:00:36
7/15/2019 8:22:58 PM 0:01:48
7/15/2019 10:35:17 PM 0:00:13
7/15/2019 10:36:58 PM 0:00:25
7/15/2019 10:37:32 PM 0:00:13

7/16/2019 6:08:10 PM 0:02:19
7/16/2019 6:48:39 PM 0:01:44
7/16/2019 6:55:39 PM 0:01:53
7/16/2019 10:53:13 PM 0:00:10
7/16/2019 10:55:16 PM 0:00:12

7/17/2019 1:36:52 PM 0:02:01
7/17/2019 3:36:02 PM 0:02:18
7/17/2019 3:47:08 PM 0:02:05
7/17/2019 7:27:24 PM 0:01:57
7/17/2019 7:51:46 PM 0:02:09
7/17/2019 8:59:44 PM 0:02:06

7/18/2019 12:24:52 PM 0:01:49
7/18/2019 12:50:00 PM 0:01:52
7/18/2019 1:15:00 PM 0:02:02
7/18/2019 8:24:42 PM 0:02:16
7/18/2019 9:01:30 PM 0:01:51
7/18/2019 9:34:25 PM 0:02:19

7/19/2019 1:12:00 PM 0:01:59
7/19/2019 1:25:59 PM 0:01:51
7/19/2019 2:44:35 PM 0:02:00
7/19/2019 3:00:38 PM 0:02:14
7/19/2019 3:12:32 PM 0:02:08
7/19/2019 3:16:14 PM 0:02:05
7/19/2019 3:34:24 PM 0:00:20
7/19/2019 4:58:47 PM 0:00:16
7/19/2019 6:29:02 PM 0:00:20
7/19/2019 6:39:04 PM 0:04:18
7/19/2019 6:47:04 PM 0:00:16
7/19/2019 6:51:34 PM 0:00:14
7/19/2019 7:20:52 PM 0:00:27
7/19/2019 7:28:22 PM 0:00:11
7/19/2019 7:51:05 PM 0:09:01
7/19/2019 9:00:33 PM 0:00:20
7/19/2019 9:15:45 PM 0:02:12

7/20/2019 7:30:03 AM 0:00:10
7/20/2019 7:38:33 AM 0:00:14
7/20/2019 8:22:13 AM 0:00:47
7/20/2019 8:47:57 AM 0:00:17
7/20/2019 10:16:09 AM 0:00:26
7/20/2019 2:28:15 PM 0:02:01
7/20/2019 2:34:19 PM 0:01:57
7/20/2019 2:44:00 PM 0:01:57
7/20/2019 2:46:32 PM 0:01:58
7/20/2019 2:54:24 PM 0:01:53
7/20/2019 2:59:58 PM 0:02:00
7/20/2019 3:02:58 PM 0:02:01
7/20/2019 3:11:01 PM 0:01:53
7/20/2019 3:19:02 PM 0:02:10
7/20/2019 3:26:02 PM 0:01:49
7/20/2019 7:40:48 PM 0:01:58
7/20/2019 7:51:13 PM 0:01:56
7/20/2019 8:17:56 PM 0:02:05
7/20/2019 9:10:31 PM 0:02:07

7/24/2019 1:14:13 PM 0:02:11
7/24/2019 1:26:31 PM 0:02:13
7/24/2019 3:30:54 PM 0:00:15
(Cable Modem Reset using
Spectrum Web reset utility)

7/25/2019 2:09:09 PM 0:01:54
7/25/2019 2:31:32 PM 0:00:15

7/26/2019 12:29:31 PM 0:00:15
7/26/2019 12:48:12 PM 0:02:03
7/26/2019 2:24:11 PM 0:02:03
7/26/2019 2:30:42 PM 0:02:11
7/26/2019 2:45:56 PM 0:02:08
7/26/2019 2:49:31 PM 0:02:02

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A Web search for others with a similar problem turned up information from other providers' user groups, some of which are populated by users who must really be into this stuff.  I am not, but have put a PDF copy of the info dump and logs from my Arris modem up on Dropbox, hoping that maybe someone monitoring this forum can provide some insight into what may be going on.

https://www.dropbox.com/s/5y3taq8rui26oxg/Arris%20Modem.pdf?dl=0

Any help is appreciated; I'd really like to have a handle on this before having someone from Spectrum come out and take a look.  Many thanks!

8 REPLIES 8
Helper

Re: Frequent Internet dropouts, all about 2 minutes each.

Describe the connections from the modem as far back to the tap as you can access...wall outlets, splitters, filters, amps, length of coax runs, etc.  

 

Signals don't look bad overall but the upstream power levels are a tad bit high and uneven. Prior to a couple of weeks ago I assume this behavior was not present? Could be loose connections or hungry squirrels. Has there been recent heavy rains? 

Browser

Re: Frequent Internet dropouts, all about 2 minutes each.

Thanks for the reply, reds, and for looking at my numbers.   I have no point of reference with regard to those and appreciate your insight.  Yes, operation has been flawless for the past several years, I don't think we had a single outage that didn't conincide with a power loss.  No bad weather lately and the cable is underground.

From what you say, the numbers must be in the range of what's common, so does that mean we're experiencing an intermittent connection or maybe a flakey cable company amplifier?  And wouldn't that probably affect other users in our immedite area?  Would a tech with test gear be able to tell anything when the connection is solid, or would he have to be watching when a failure happened?

The modem connects with a 3-foot F cable to a grounded protection feed-through; the F connector on the other side of that is the underground cable, and I have no idea where that splits or terminates.  Again, thanks for your attention.

Proven Sharer

Re: Frequent Internet dropouts, all about 2 minutes each.

The log file entries with a date Jan 1, 1970 occurred after the modem lost power; either you unplugged the power supply or the  commercial power went out for a few seconds.  I also notice in the logs that your modem shows numerous T3 and T4 time-out messages, as well as high ratios of uncorrectible errors relative to corrected packets on all eight DS channels.  One possibe cause of those errors is that a cellphone carrier may have recently installed a mini-cell site in your area to improve their 4G LTE signal coverage and there may be ingress interference into the cable TV system. This is a royal pain for Spectrum to track down but don't rule it out. 

 

Before you go any further, first visually verify that the grounded feedthrough is securely connected to the electrical service ground wire from your breaker panel.  This is absolutely required by National Electrical Code for electrical safety.

 

Next, if you have a spare, swap out the cable between the grounding block and your modem.  It MUST be RG6 type with multiple layers of foil shielding and new compression style connectors, NOT RG59/U which uses just one copper braid and obsolete hex crimp connectors.  If you don't have a spare the Spectrum tech can make one for you in just a few minutes. 

 

There is probably an intermittent connection somewhere between your modem and the node serving your neighborhood.  You mentioned that the incoming drop cable is buried underground, so if the pedestal is accessible and the cover is not locked, take a look inside.  Verify that the F connector on the cable leading to your home is "tight and bright."  No wiggles, no corrosion, no moisture, and all of the copper center wires are shiny color.

If these steps don't solve the disconnect issue, call Spectrum and schedule a visit by a home service tech.

Browser

Re: Frequent Internet dropouts, all about 2 minutes each.

Good info, Karl!

However, I know for a fact that mains and/or wall-wart secondary power was never lost to the modem.  Could there be a thermal or other problem in the modem that would cause a similar error code?  I wondered about those 1970 entries and am glad to know what causes them.  Looking back at the log sample, it appears that both instances of a 1970 entry came right after the log entry: "Received Response to Broadcast Maintenance Request...".  Does that have any significance?  I just now checked today's log entries and the same message sequence is there.  If there's a chance that the modem is acting up I could get another and pop it in, or maybe try a different wall-wart first.  There are Internet dropouts that are not coincident with the 1970 entries, however, and it seems questionable that there could be both a both a modem issue and a signal drop from the ISP.

Sharer

Re: Frequent Internet dropouts, all about 2 minutes each.

Keep an eye on those upstream power levels. I remember my old Motorola would reboot as soon as signal quality degraded to the point that upstream tried to go over 51.

If it starts going higher than 49, need to take as close a look as you can at anything that may be degrading signal quality. Some examples:

Damaged/crimped shielding, loose/corroded connections/splitters/etc.

excess cabling that is bunched/coiled up (use shorter cables that run a "straight" line to reduce losses and guard against inducted noise)

overheating components (ie: power adaptor could increase noise if it isn't regulating power right)

any nearby electrical/mechanical devices that may generate any interference (motors, fluorescent lighting, microwaves, poorly shielded speakers/electronics, etc.).
Browser

Re: Frequent Internet dropouts, all about 2 minutes each.

On red's urging in the first reply to my original post, I located the underground box where the main cable from Spectrum branches off to 4 homes in my area.   Spiders in there, but in poking around with a stick to expose the tag identifying my coax 'drop,' I must have "fixed" something, because since then I have not had a single dropout in almost 4 days, or a single entry in the modem's log.  I am reluctant to ask for a service call, but obviously something needs to be tightened-up in that box.  

One thing I noticed that seems peculiar is that there's a short length (maybe 2 feet) of coax between Spectrum's block with all the F connectors and the coax to my house.  I don't understand why my drop cable isn't just screwed into the block, the extra 2 feet of cable doesn't seem to serve any useful purpose... lots of slack without it.

Anyhow, thanks to all who responded, it's good to learn as much as I can about this business.

Helper

Re: Frequent Internet dropouts, all about 2 minutes each.

By poking around in the tap and now your connection seems to be fixed, it leads me to believe that the connections are loose or even corroded. Keep a close eye on your connection and call for service if you continue to experience problems.

 

Two feet of coax really isn't enough to make much of a difference, but the added connectors could definitely be a weak point in the chain if they are loose or not done correctly.

Highlighted
Proven Sharer

Re: Frequent Internet dropouts, all about 2 minutes each.

I'm definitely with @reds91185 on this one.  A 7/16" open end wrench (and a pair of pliers to hold the other side) is all you  need to ensure any formerly loose F connectors are sufficiently dry and tight, and the center wires are clean and shiny. 

If you think that the extra two foot length of drop cable overstuffs the pedestal, you could in theory remove it yourself, but it would be better to have the tech stop over and ask why they would connect it in that fashion. There's a good reason for letting them do it: the rule of You Touched it Last.  When you moved the cables and your service suddenly got better, one of your neighbors might have gone the other direction.  It wouldn't hurt to ask around and let THEM make the call for service if needed.

HINT: The service pedestal might have been cabled that way in the past to insert an "internet-only" or "no premium" filter; those are no longer utilized.