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Continuous disconnects. Modem reboots Please help.

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Frequent Visitor

Continuous disconnects. Modem reboots Please help.

I sure hope somebody can help us out here. I am going to try to give as much detail as I can as compactly as I can. 
 
4 of us have been working from home since March. We have had no issues with the internet service. A few weeks ago we upgraded our internet service. Shortly after when we would all sign onto the vpn on our work computers our router would restart. Everything would come back on for about 2 to 3 minutes and it would restart again.  So a continuous loop of the router powering down and restarting. Now we have the added issue of the modem powering down and restarting which it had not been doing. However, during our troubleshooting we did realize that even though the modem would have all the lights properly lit, if I plugged my personal pc into the modem with an ethernet cable it would tell me there was no internet. But now, the modem is actually powering down and restarting. 
 
Since it started here are the steps we have taken: 
Purchase a new Netgear Nighthawk RAX80 router- Didn't help
Purchase a new Arris Surboard SB8200 modem- Didn't help
Contacted our tech support at work- They said it was our ISP because of latency and packet loss issues. 
Contacted Netgear customer support-They got us back online but it only lasted about an hour. 
Contacted Comcast customer support.  Oh boy, Comcast customer support. 
Comcast told us there were errors with the modem. They reset it several times. Finally they sent a technician. First technician said it was the outlet. Changing outlets/circuits didn't help. Second technician found issues with the lines and replaced everything from the pole to the modem.  Worked for a day and it has started again. But, we just signed onto the work vpn today. 
I chatted with Comcast again today. Again they said we can't help we have to send a technician. I specifically asked about the errors I was seeing from the modem and they avoided answering any questions related to that. 
I am going to try to attach screen shots of the error log in case that would help diagnose the issue.  Hopefully I can do it correctly. 
This is so upsetting because we aren't talking about playing video games. We are talking about our jobs. We can't just keep taking time off work because we don't have internet access. 
 
 
 
 
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Diamond Problem Solver

Re: Modem continuously restarting. Please help.

The downstream levels that you posted, and you didn’t post them all, are all at the low end of the acceptable range.Ch 34 has nothing, there maybe more but unfortunately they’re missing on your post.

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Frequent Visitor

Re: Modem continuously restarting. Please help.

Thank you for the quick response.

I apologize. I did leave some of the screen shots out.

They are attached now. 

What do we do to correct this? 

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Frequent Visitor

Re: Modem continuously restarting. Please help.

We just ended our 4th technician visit. He said everything was "perfect". Clearly it isn't. He wasn't interested in my error logs. He said he didn't know how to read them.
We are truly desperate at this point and would appreciate any help we can get. We can't work without Internet. We used all of our days off last week with this outage.
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Expert

Re: Modem continuously restarting. Please help.

See if anything here applies;

The downstream power is on the low / weak side and it may be intermittently fluctuating even lower to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

In a self troubleshooting effort to try to obtain better connectivity / more wiggle room, check to see if there are there any excess/unneeded coax cable splitters in the line leading to the modem that can be eliminated/re-configured. Any splitters that remain should be high quality and cable rated for 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test<br><br>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 check for and clean off any corrosion / oxidation on the center wire and put them back together again, then perhaps it's best to book a tech visit to investigate and correct.


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Frequent Visitor

Re: Modem continuously restarting. Please help.

There are no splitters in the house. We have one coax cable that goes to the modem. The tech just ran new cable from the pole and into the house. So there shouldn't be any corrosion, etc. I'm not sure about a splitter at the pole. Surely if it was possible to not have one they would not have left it or added it.
After the tech left today I called Comcast again to try to get help again. She said the modem wasn't configured properly. So I contacted Arris. They said it was but the power was too low and to ask my ISP to increase it. I believe it was 4 channels with 43, 43. 44, and 45.
So I will call Comcast again the morning and ask for them to look at that.
She told me she couldn't see any errors with the modem. I don't understand how that can be when I see "no internet" with an ethernet directly connected to my pc. And when I see the lights go out on my modem and watch it restart. And I see the error log. It sounds like the conversation from my modem to Comcast is okay. But the conversation from Comcast to me is not. I'm just confused why Comcast can't see it.
Thank you for the information. I will check back in tomorrow with any updates.
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Frequent Visitor

Re: Modem continuously restarting. Please help.

What causes low downstream power?
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Diamond Problem Solver

Re: Modem continuously restarting. Please help.

There’s nothing wrong with your upstream. After the last tech visit what does the downstream levels look like. If you’re going from tap to ground block to modem with absolutely nothing in between, you shouldn’t be as far in the negatives as you were.

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Frequent Visitor

Re: Modem continuously restarting. Please help.

This is what it looks like this morning. For what it's worth, he tech did not do anything on his visit yesterday. He checked the cable connections and said everything was fine. 

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Frequent Visitor

Re: Modem continuously restarting. Please help.

I have a bit of an update with a little more information but still no solution. 

 

I was finally connected with a local supervisor today. He told me that they weren't able to see any issues with our modem on their side. I suppose this is why I have had such a hard time getting help in the first place, because they couldn't verify the issue. I had spoken to a CS agent earlier in the day. She suggested that we switch out our Arris modem for a Comcast modem. I agreed and she set up the appointment for a few hours later. 

 

While I was talking to Randy, the supervisor, the guy with the modem showed up. Randy & I had agreed not to go ahead with the modem switch. While the man with the modem was at my house he actually witnessed my modem shutting down and restarting. I showed him the modem error log and took a picture of it and sent it to Randy. 

 

So now they have an eye witness that they trust and documentation of the errors. Randy said he sent a maintenance crew to the node to check things there. Turns out they had an outage so they had to stop to go work on that. 

 

Well Randy called me back this evening and told me they really didn't think it was anything beyond my house/lines because there were no other complaints in my immediate neighborhood. So he was going to send another tech out tomorrow to check for voltage in the lines outside.  He said they were really stumped but that they would continue the process of elimination until they figured it out.  I really appreciate Randy. I really wish my income didn't depend on this internet service. 

 

So to recap the issue, the modem shuts down and reboots and we lose internet connection at intermittent intervals. Sometimes it's 30 minutes before it happens. Sometimes it's every 2 to 3 minutes for hours. 

 

These are the modem errors we see: 

Resetting the cable modem due to docsDevResetNow

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing

No Ranging Response received - T3 time-out;CM-

Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out

Honoring MDD; IP provisioning mode = IPv6"

DS profile assignment change. DS Chan ID: 32; Previous Profile: ; New Profile: 1 2 3.;CM

 

Any thoughts or ideas?

 

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Frequent Visitor

Re: Modem continuously restarting. Please help.

When we replaced the modem we bought the exact same one we had. Do you suppose a different brand of modem would change anything?
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Diamond Problem Solver

Re: Modem continuously restarting. Please help.

Ask why you are in the negatives at your modem. Ask what the levels are at the tap. Maybe hook up your modem at the ground block and post your levels. So you have something to compare with

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Frequent Visitor

Re: Modem continuously restarting. Please help.

I will do that. I'm going to have to ask the internet how to hook my modem that way because I have no idea. 🙂