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user_ev2f69
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Sunday, June 2nd, 2024 7:08 PM

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Experiencing slow internet speed after few days - fixed by modem reboot

Very long time Xfinity customer and we've had this setup for several years without issues. Using a Motorola 8600 cable modem. Starting a little over a few months ago, noticed that Internet speeds drop and latency increases after several days (could be up to 2 or 3 weeks sometimes). This is then fixed when the cable modem is rebooted. The cycle then repeats. The duration is unpredictable - could be days, weeks.

I suspect cable or signal issues more than modem issues. Here are the stats from the modem (replaced the cable from the wall to the modem a few days ago) - can someone tell me if any of these numbers look off and if so, what should I do next?

Downstream Bonded Channels  
  
   Channel Lock Status Modulation Channel ID Freq. (MHz) Pwr (dBmV) SNR (dB) Corrected Uncorrected
   1 Locked QAM256 44 669.0 -5.3 43.6 73940 122384
   2 Locked QAM256 13 471.0 -7.4 43.0 3369 4742
   3 Locked QAM256 14 477.0 -7.3 43.0 3518 4688
   4 Locked QAM256 15 483.0 -6.9 43.2 2898 3897
   5 Locked QAM256 16 489.0 -6.7 43.4 3357 4861
   6 Locked QAM256 17 495.0 -6.5 42.5 3470 4474
   7 Locked QAM256 18 507.0 -6.6 43.4 3429 4479
   8 Locked QAM256 19 513.0 -6.3 43.9 2581 3433
   9 Locked QAM256 20 519.0 -6.6 43.5 2712 3714
   10 Locked QAM256 21 525.0 -6.1 43.6 2031 2359
   11 Locked QAM256 22 531.0 -6.8 42.8 2865 3759
   12 Locked QAM256 23 543.0 -6.8 43.5 2997 4020
   13 Locked QAM256 24 549.0 -6.7 43.6 2170 2408
   14 Locked QAM256 25 555.0 -6.6 43.7 2444 2901
   15 Locked QAM256 26 561.0 -6.7 43.7 2354 2135
   16 Locked QAM256 27 567.0 -6.4 42.3 2359 1933
   17 Locked QAM256 28 573.0 -6.6 42.7 2342 2362
   18 Locked QAM256 29 579.0 -6.4 43.3 2281 2490
   19 Locked QAM256 30 585.0 -6.6 40.7 2217 2412
   20 Locked QAM256 31 591.0 -6.4 38.3 2012 1503
   21 Locked QAM256 32 597.0 -6.6 41.7 2295 2367
   22 Locked QAM256 33 603.0 -6.5 41.9 1681 1146
   23 Locked QAM256 34 609.0 -6.4 42.5 2193 2530
   24 Locked QAM256 35 615.0 -6.2 42.6 1431 941
   25 Locked QAM256 36 621.0 -6.5 38.3 2699 2969
   26 Locked QAM256 37 627.0 -5.8 42.7 1478 1315
   27 Locked QAM256 38 633.0 -6.0 37.4 1873 1719
   28 Locked QAM256 39 639.0 -5.6 43.5 1571 892
   29 Locked QAM256 40 645.0 -5.6 42.8 1573 1343
   30 Locked QAM256 41 651.0 -5.9 43.6 1462 1260
   31 Locked QAM256 42 657.0 -5.4 43.9 1535 984
   32 Locked QAM256 43 663.0 -5.9 43.5 80311 114097
   33 Locked OFDM PLC 193 722.0 -4.6 43.3 177764066 312


   Upstream Bonded Channels  
  
   Channel Lock Status Channel Type Channel ID Symb. Rate (Ksym/sec) Freq. (MHz) Pwr (dBmV)
   1 Locked SC-QAM 17 5120 16.4 58.0
   2 Locked SC-QAM 18 5120 22.8 58.0
   3 Locked SC-QAM 19 5120 29.2 58.0
   4 Locked SC-QAM 20 5120 35.6 58.0
   5 Locked SC-QAM 21 2560 40.4 55.0
   6 Locked SC-QAM 22 2560 10.4 55.0

Question

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Updated 

4 months ago

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Official Solution

user_ev2f69

8 Messages

4 months ago

An update on this - while things improved after the tech visit, I still had issues requiring periodic modem reboot. But a few weeks back I saw the xfinity truck in my street - after that I've not had any issues so far. Fingers crossed, the issue is fixed for good now. Thanks all for the help!

1

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XfinityAldrik

Official Employee

 • 

1.7K Messages

Thanks again for reaching out to us @user_ev2f69! I’m glad our awesome local teams were able to get this taken care of!

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
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4 months ago

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Accepted Solution

EG

Expert

 • 

107.1K Messages

6 months ago

Yep. The downstream power is low / weak and the upstream power is way too high / out of spec. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of channels.

In an effort to try to obtain better connectivity / more wiggle room, check to see if there are 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 from Home Depot, Target, Wal-Mart, etc. Splitters should be swapped with known to be good / new ones to test.

Also check the coax cable for any damage such as cuts, nicks, abrasions, kinks, sharp bends, etc.

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.


Good luck with it !

2

0

user_ev2f69

8 Messages

Thanks. There are no splitters and at least the accessible cables are in good condition or newly replaced. How do I book a tech visit? Is this something I need to pay for or is it free?

6 months ago

0

XfinityDilary

Official Employee

 • 

1.8K Messages

 

Thanks for escalating the issue, @EG. We can help set up an appointment from here @user_ev2f69. Typically, we may charge for this visit if we determine the problem is not caused by Comcast equipment or service. This is something the technician will determine at the time of the visit. Could you please send our team a Direct Message with your name and service address? Our team can take a further look at this issue.

 

To send a Direct Message:

Click "Sign In" if necessary

• Click the "Direct Messaging chat" icon

• Click the "New message" (pencil and paper) icon

• Type "Xfinity Support" in the "To:" line and select "Xfinity Support" from the drop-down list which appears. The "Xfinity Support" graphic replaces the "To:" line

• Type your message in the text area near the bottom of the window

• Press Enter to send it


 
 
 
 
 

 

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

6 months ago

EG

Expert

 • 

107.1K Messages

6 months ago

@user_ev2f69 

I'm going to escalate your issue to the Comcast corporate employees (The Digital Care Team) who are available to these boards. They will be able to book a tech visit for you. You should get a reply here in your topic. If the problem is found to be with their wiring / equipment rather than yours, there won't be a charge. Good luck !

(edited)

1

user_ev2f69

8 Messages

@EG​ thank you! Hopefully they can figure out and resolve the issue.

6 months ago

0

EG

Expert

 • 

107.1K Messages

6 months ago

@user_ev2f69 

Quite welcome ! Please post back here with how things turn out.

2

0

user_ev2f69

8 Messages

Tech came today - they found an 8-way splitter from the main cable line which they bypassed so main line goes straight to the modem (since I don't use any of the other cable outlets this works for me). That improved the connection levels somewhat. Tech also said there's an issue with my main line and that Xfinity will be sending someone to fix it on the outside in the next two to three weeks. Looking forward to that issue being fixed.

6 months ago

XfinityThomasA

Official Employee

 • 

1.8K Messages

That is great news, and thank you for keeping us apprised user_ev2f69. I set a reminder, so our team can check back in with you and confirm this issue is resolved in the upcoming weeks via our direct message chat. If anything were to come up in between time, please message us in our open direct message chat, and we'll pick things right back up. 

 

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

6 months ago

0

EG

Expert

 • 

107.1K Messages

6 months ago

@user_ev2f69 

Thanks for the update ! For curiosity sake, Please post what the modems signal stats look like now.

3

0

user_ev2f69

8 Messages

 Downstream Bonded Channels  
  
   Channel Lock Status Modulation Channel ID Freq. (MHz) Pwr (dBmV) SNR (dB) Corrected Uncorrected
   1 Locked QAM256 44 669.0 4.6 44.7 67956 178038
   2 Locked QAM256 13 471.0 2.3 44.2 3050 2366
   3 Locked QAM256 14 477.0 2.4 44.5 3098 2496
   4 Locked QAM256 15 483.0 2.6 44.4 2475 2049
   5 Locked QAM256 16 489.0 2.8 44.7 2480 2669
   6 Locked QAM256 17 495.0 2.8 43.9 2333 1940
   7 Locked QAM256 18 507.0 3.0 44.8 2375 1920
   8 Locked QAM256 19 513.0 3.3 45.1 2185 1686
   9 Locked QAM256 20 519.0 3.1 45.0 2243 2082
   10 Locked QAM256 21 525.0 3.3 44.9 1920 1141
   11 Locked QAM256 22 531.0 3.0 44.1 2061 1617
   12 Locked QAM256 23 543.0 2.8 44.9 1929 1631
   13 Locked QAM256 24 549.0 3.0 45.1 1671 943
   14 Locked QAM256 25 555.0 2.9 45.0 1792 1274
   15 Locked QAM256 26 561.0 3.0 45.1 1745 751
   16 Locked QAM256 27 567.0 3.1 43.9 1829 958
   17 Locked QAM256 28 573.0 3.0 44.5 1202 934
   18 Locked QAM256 29 579.0 3.1 44.8 1576 931
   19 Locked QAM256 30 585.0 2.9 39.4 1295 1099
   20 Locked QAM256 31 591.0 3.2 38.0 1335 684
   21 Locked QAM256 32 597.0 3.0 43.4 1495 814
   22 Locked QAM256 33 603.0 3.5 43.0 957 524
   23 Locked QAM256 34 609.0 3.4 44.8 1334 840
   24 Locked QAM256 35 615.0 3.7 43.9 921 333
   25 Locked QAM256 36 621.0 3.5 43.6 1361 1067
   26 Locked QAM256 37 627.0 3.8 44.4 990 591
   27 Locked QAM256 38 633.0 3.9 44.8 1322 703
   28 Locked QAM256 39 639.0 4.2 44.6 723 354
   29 Locked QAM256 40 645.0 4.3 45.4 1018 597
   30 Locked QAM256 41 651.0 4.1 45.3 692 465
   31 Locked QAM256 42 657.0 4.4 45.3 991 363
   32 Locked QAM256 43 663.0 4.4 45.2 120372 268162
   33 Locked OFDM PLC 193 722.0 5.8 45.1 65688519 159


   Upstream Bonded Channels  
  
   Channel Lock Status Channel Type Channel ID Symb. Rate (Ksym/sec) Freq. (MHz) Pwr (dBmV)
   1 Locked SC-QAM 17 5120 16.4 52.8
   2 Locked SC-QAM 18 5120 22.8 54.3
   3 Locked SC-QAM 19 5120 29.2 53.8
   4 Locked SC-QAM 20 5120 35.6 52.5
   5 Locked SC-QAM 21 2560 40.4 51.3
   6 Locked SC-QAM 22 2560 10.4 51.3

6 months ago

0

XfinityShawn

Official Employee

 • 

1.1K Messages

 

user_ev2f69 We appreciate the update. If you need further assistance, then we will help you by DM.

 

I am an Official Xfinity Employee.
Official Employees are from multiple teams within Xfinity: CARE, Product, Leadership.
We ask that you post publicly so people with similar questions may benefit from the conversation.
Was your question answered? Please, mark a reply as the Accepted Answer.tick

6 months ago

0

EG

Expert

 • 

107.1K Messages

@user_ev2f69​ 

It was better but the upstream power was still too high.

(edited)

I am not a Comcast Employee.
I am a Customer Expert volunteering my time to help other customers here in the Forums.
We ask that you post publicly so people with similar questions may benefit from the conversation.

Was your question answered? Please mark an Accepted Answer!tick

4 months ago

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