Recently upgraded my home connection speed to the 900/20 plan. When I made the switch I was informed to upgrade my cable modem from my older model to be compatible with the new speed.
Now my connection is unstable. The speed will fluctuate wildly throughout the day seemingly at random. It will drop as low as 15-45 down, then within 3-5 minutes be back to 600+ down. (Tests run through independent speed test sites using a wired connection).
Restarting the modem (either manually or through the Xfinity website) seems to do nothing.
Here are the current connection stats since the last restart. Modem has only been up and running for 15 hours. (Event log is also filled with notices and warnings).
| Downstream Bonded Channels |
 |
|
|
|
| Channel |
Lock Status |
Modulation |
Channel ID |
Freq. (MHz) |
Pwr (dBmV) |
SNR (dB) |
Corrected |
Uncorrected |
| 1 |
Locked |
QAM256 |
5 |
543.0 |
-6.9 |
39.2 |
154 |
85 |
| 2 |
Locked |
QAM256 |
2 |
525.0 |
-5.6 |
41.4 |
41 |
11 |
| 3 |
Locked |
QAM256 |
3 |
531.0 |
-7.5 |
40.3 |
249 |
83 |
| 4 |
Locked |
QAM256 |
4 |
537.0 |
-4.9 |
37.9 |
41 |
28 |
| 5 |
Locked |
QAM256 |
6 |
555.0 |
-4.1 |
31.1 |
159268030 |
422859 |
| 6 |
Locked |
QAM256 |
7 |
561.0 |
-6.4 |
27.7 |
495878760 |
20688252 |
| 7 |
Locked |
QAM256 |
8 |
567.0 |
-4.0 |
34.2 |
16 |
0 |
| 8 |
Locked |
QAM256 |
9 |
573.0 |
-5.8 |
30.7 |
48268 |
4312 |
| 9 |
Locked |
QAM256 |
10 |
579.0 |
-5.6 |
39.3 |
5 |
0 |
| 10 |
Locked |
QAM256 |
11 |
585.0 |
-6.2 |
40.6 |
65 |
26 |
| 11 |
Locked |
QAM256 |
12 |
591.0 |
-6.9 |
40.3 |
167 |
102 |
| 12 |
Locked |
QAM256 |
13 |
597.0 |
-5.5 |
33.1 |
819 |
26 |
| 13 |
Locked |
QAM256 |
14 |
603.0 |
-7.5 |
27.0 |
2760931 |
2804352 |
| 14 |
Locked |
QAM256 |
15 |
609.0 |
-5.7 |
37.9 |
2980 |
1962 |
| 15 |
Locked |
QAM256 |
16 |
615.0 |
-6.4 |
40.8 |
33 |
4 |
| 16 |
Locked |
QAM256 |
17 |
621.0 |
-6.2 |
40.1 |
43 |
7 |
| 17 |
Locked |
QAM256 |
18 |
627.0 |
-6.3 |
38.3 |
36 |
1 |
| 18 |
Locked |
QAM256 |
19 |
633.0 |
-7.4 |
39.6 |
11 |
0 |
| 19 |
Locked |
QAM256 |
20 |
639.0 |
-5.8 |
40.1 |
0 |
0 |
| 20 |
Locked |
QAM256 |
21 |
645.0 |
-8.2 |
39.5 |
329 |
94 |
| 21 |
Locked |
QAM256 |
22 |
651.0 |
-7.3 |
40.1 |
49 |
0 |
| 22 |
Locked |
QAM256 |
23 |
657.0 |
-6.8 |
40.5 |
12 |
0 |
| 23 |
Locked |
QAM256 |
24 |
663.0 |
-8.1 |
39.7 |
68 |
92 |
| 24 |
Locked |
QAM256 |
25 |
669.0 |
-5.4 |
41.2 |
0 |
0 |
| 25 |
Locked |
QAM256 |
26 |
675.0 |
-6.8 |
39.7 |
2 |
0 |
| 26 |
Locked |
QAM256 |
27 |
681.0 |
-5.2 |
41.5 |
30 |
1 |
| 27 |
Locked |
QAM256 |
28 |
687.0 |
-7.0 |
40.5 |
85 |
42 |
| 28 |
Locked |
QAM256 |
29 |
693.0 |
-6.9 |
40.5 |
47 |
25 |
| 29 |
Locked |
QAM256 |
30 |
699.0 |
-6.2 |
41.0 |
35 |
48 |
| 30 |
Locked |
QAM256 |
31 |
705.0 |
-8.5 |
39.6 |
3756 |
8585 |
| 31 |
Locked |
QAM256 |
32 |
711.0 |
-7.9 |
40.0 |
4147 |
6380 |
| 32 |
Locked |
OFDM PLC |
37 |
762.0 |
-8.3 |
37.0 |
384425736 |
57042 |
|
| Upstream Bonded Channels |
|
|
|
|
| Channel |
Lock Status |
Channel Type |
Channel ID |
Symb. Rate (Ksym/sec) |
Freq. (MHz) |
Pwr (dBmV) |
| 1 |
Locked |
SC-QAM |
9 |
5120 |
35.6 |
47.3 |
| 2 |
Locked |
SC-QAM |
10 |
5120 |
29.2 |
53.5 |
| 3 |
Locked |
SC-QAM |
11 |
5120 |
22.8 |
51.8 |
| 4 |
Locked |
SC-QAM |
12 |
5120 |
16.4 |
50.5 |
|
Event log warnings all read
13:19:22
Tue Jan 25 2022 |
|
Warning (5) |
|
MDD message timeout |
EG
Expert
•
111.3K Messages
3 years ago
The upstream power is too high (already out of spec on channel #2) and it may be intermittently fluctuating even higher out of spec. And the downstream power is on the low weak side. 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 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 5-1000 MHz, bi-directional, and no gold colored garbage from Radio Shack, Home Depot, Target, 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, 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 !
3
EG
Expert
•
111.3K Messages
3 years ago
Please post back with how things turn out.
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0
sbujak1
Regular Visitor
•
7 Messages
3 years ago
Modem: Motorola MB861. Service 900 MBS everything looks good, except Ch. 32 has a large number of corrected errors. see attached images. All connections were checked and cleaned with good quality, contact cleaner/degreaser except up on the pole. My speed is fine. 800-900+ MBS can someone command on CH32 errors. Best Regards
0
0
EG
Expert
•
111.3K Messages
3 years ago
@sbujak1
Please create a new topic of your own here on this board detailing your issue. Thanks. The original poster has not returned. 6-month-old dead thread is now being closed.
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0