Browser

Must reboot modem to regain speeds

Approximately once every three days I notice my internet browsing speeds slow to a crawl. The internet still technically works, but the speeds are atrocious. My download rate is about 2 Mbps but my upload remains perfect at 20 Mbps. This issue has been occuring for about six months now. The issue is immediately resolved once I power cycle my modem.

 

On the 300 Mbps/20 Mbps plan. The modem is a Netgear CM500-100NAS. I've used it for four months. Prior to this, I had a TP-Link TC-7620 that I used for about 1.5 years. The reason I stopped using it? Yep, you guessed it, because of the issue I just described. I thought it was my modem, but sure enough it must be something else.

 

Here are the logs from the last time this happened. I will be obtaining the logs every time this occurs from this point forward. Any help would be much appreciated.

 

Time

Priority

Description

2018-3-20, 23:46:34

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:46:35

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:46:36

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:46:37

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:46:38

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:46:40

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:46:41

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:46:42

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:46:45

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:46:45

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:46:46

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:46:48

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:46:49

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:47:06

Critical (3)

No UCDs Received - Timeout;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:47:07

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:47:24

Critical (3)

No UCDs Received - Timeout;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:47:25

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:47:42

Critical (3)

No UCDs Received - Timeout;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:47:43

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:48:00

Critical (3)

No UCDs Received - Timeout;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:48:01

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:48:17

Critical (3)

No UCDs Received - Timeout;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:48:19

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:48:40

Critical (3)

No UCDs Received - Timeout;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:48:42

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:48:58

Critical (3)

No UCDs Received - Timeout;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:49:00

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:49:16

Critical (3)

No UCDs Received - Timeout;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:49:17

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:49:34

Critical (3)

No UCDs Received - Timeout;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:49:35

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

2018-3-20, 23:49:52

Critical (3)

No Ranging Response received - T3 time-out;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:17:10:86:85:a0;CM-QOS=1.0;CM-VER=3.0;

2018-3-23, 08:52:56

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:17:10:86:85:a0;CM-QOS=1.1;CM-VER=3.0;

1970-1-1, 00:00:21

Critical (3)

SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;

1970-1-1, 00:00:27

Notice (6)

Overriding MDD IP initialization parameters; IP provisioning mode = IPv6

2018-3-23, 14:30:27

Error (4)

Missing BP Configuration Setting TLV Type: 17.8;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:17:10:86:85:a0;CM-QOS=1.1;CM-VER=3.0;

2018-3-23, 14:30:27

Error (4)

Missing BP Configuration Setting TLV Type: 17.9;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:17:10:86:85:a0;CM-QOS=1.1;CM-VER=3.0;

2018-3-23, 17:29:37

Warning (5)

MDD message timeout;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:17:10:86:85:a0;CM-QOS=1.1;CM-VER=3.0;

2018-3-25, 03:18:35

Critical (3)

Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:17:10:86:85:a0;CM-QOS=1.1;CM-VER=3.0;

2018-3-25, 09:15:46

Warning (5)

MDD message timeout;CM-MAC=b0:b9:8a:db:41:58;CMTS-MAC=00:17:10:86:85:a0;CM-QOS=1.1;CM-VER=3.0;

 

 

 

Apply               Cancel     

Frequency start Value

This field below allows you to modify the frequency the cable modem start with its scan during initialization and registration. Enter the new start frequency and restart the cable modem for it to take effect.

Starting Frequency

 

 

Startup Procedure

Procedure

Status

Comment

Acquire Downstream Channel

543000000 Hz

Locked

Connectivity State

OK

Operational

Boot State

OK

Operational

Security

Enabled

BPI+

IP Provisioning Mode

IPv6 Only

ipv6Only(1)

 

Downstream Bonded Channels

Channel

Lock Status

Modulation

Channel ID

Frequency

Power

SNR

Correctables

Uncorrectables

1

Locked

QAM256

15

543000000 Hz

0.7 dBmV

40.2 dB

0

0

2

Locked

QAM256

28

621000000 Hz

-2.3 dBmV

37.6 dB

532592

111734

4

Locked

QAM256

12

525000000 Hz

0.9 dBmV

40.9 dB

0

0

5

Locked

QAM256

13

531000000 Hz

0.9 dBmV

40.5 dB

0

0

6

Locked

QAM256

10

513000000 Hz

1.2 dBmV

41.2 dB

0

0

8

Locked

QAM256

16

549000000 Hz

0.4 dBmV

40.2 dB

0

0

9

Locked

QAM256

17

555000000 Hz

0.1 dBmV

40 dB

0

0

10

Locked

QAM256

18

561000000 Hz

0.5 dBmV

40.1 dB

0

0

11

Locked

QAM256

19

567000000 Hz

0.7 dBmV

40.1 dB

0

0

12

Locked

QAM256

32

645000000 Hz

-1.5 dBmV

38.7 dB

2441298

219629

13

Locked

QAM256

21

579000000 Hz

-0.2 dBmV

38.8 dB

0

0

14

Locked

QAM256

22

585000000 Hz

0.4 dBmV

39.6 dB

0

0

15

Locked

QAM256

23

591000000 Hz

1.2 dBmV

39.8 dB

0

0

16

Locked

QAM256

24

597000000 Hz

1.6 dBmV

39.9 dB

1520

0

 

Upstream Bonded Channels

Channel

Lock Status

US Channel Type

Channel ID

Symbol Rate

Frequency

Power

1

Locked

ATDMA

2

5120 Ksym/sec

24000000 Hz

52 dBmV

2

Locked

TDMA

1

2560 Ksym/sec

19200000 Hz

52 dBmV

 

Current System TimeSmiley Frustratedun Mar 25 11:05:51 2018

7 REPLIES
Helper

Re: Must reboot modem to regain speeds

You have a coax issue somewhere...loose connections, chewed or water logged coax...that is causing your problems. It is not the modem. The upstream levels are too high and you should (probably) have 4 channels instead of 2. At 52dbmv, the upstream is at it's absolute top end and is causing the slowdowns and timeouts.

 

Can you describe the cable run from the main line to your house to each outlet (splitters, amps, length of runs, etc.)? Have you had a tech out in the past 6 months and what was their diagnosis?

Browser

Re: Must reboot modem to regain speeds

Thanks for the help!

 

It's a townhome, so I am not exactly sure on the specifics of the coaxial connections, but I will try my best.

 

4 units in the building. There are two coaxial connections in my entire unit. I'm fairly certain there is not a splitter in play. If so, it is buried in the wall somewhere that I cannot see. I'll try to find where the coaxial comes into the unit and see if there are  1 or 2 lines.

 

I haven't had anyone out recently. Every time I have in the past, I am told there is no issue, and the person leaves within 5 minutes. It's very frustrating.

 

IMO, the outside line is the culprit and water is to blame. I can't be exact, but it seems that every time it rains I experience these issues.

 

Yeah, strange that there are only 2 upstream channels. There certainly used to be 4.

Highlighted
Established Sharer

Re: Must reboot modem to regain speeds

Thanks for including the event status and signal level reports in your posting.  We need both to diagnose the kind of problems you are experiencing.  When you have both TV and internet service, your cable modem should be on the first 2-way splitter coming in from the drop cable.  Anything else causes high loss and poor signals both up and down. 

Your modem says it has very high error counts on two of the downstream channels, DS28 and DS32.  That points to ingress interference from over the air broadcast TV stations which usually is caused by corroded or loose connectors along the trunk lines or drop cable that is abraded and letting water in.  The location of both the signal leak and water leaks could be either overhead or underground; subscribers get the same bad results.  

You can look up those local TV stations at www.antennaweb.com, but  you can't always trust the channel numbers the stations ID with anymore.  If you'd rather just post your ZIP Code, we can check all stations in the area for you. 

You will need to have Spectrum send out a home service tech to verify the poor signal quality.  Print out a copy of the event and signal logs for the tech, so he can see what the modem is complaining about.  Regardless of what any phone tech support person says, DO NOT reset the modem for at least twelve hours before the service person is scheduled to arrive, and DO NOT let them try to cancel your home service call by claiming that they don't see a problem at their end! 

Browser

Re: Must reboot modem to regain speeds

Thanks for the link. No channel 28, but the local PBS is 32. 

 

Also, I do not have cable service. Just internet.

Established Sharer

Re: Must reboot modem to regain speeds

If you are only getting internet service, your modem should be connected directly to the incoming drop cable, with no splitter at all.   Did I miss seeing your ZIP Code?

Browser

Re: Must reboot modem to regain speeds

Wanted to follow up and say that a Spectrum tech came out about a month ago and let me know an external connection was lose and allowing moisture in. Since he tightened it up I have had zero issues...

 

...other than still getting 2 upload channels. Anyone know if that is expected behavior with the CM500? Admittedly, I cannot remember if I ever got 4 upload channels, but the modem certainly supports 4.

 

I've called Spectrum a few times about this, even spoken with Tier 2, and I imagine the looks on their faces are like a deer in headlights to my question. Literally no one knows what I am talking about. Don't really understand how that is possible.

Established Sharer

Re: Must reboot modem to regain speeds

I suspect your personally owned modem may have been incorrectly set up by Spectrum.  I suggest you first verify the modem's MAC ID on your account record, then call in to the Tech Help line.  Ask the agent to confirm they show your device's model number is CM500, the MAC ID is exactly as shown on the modem, and ask him to send the boot file again.  After the restart, look at the signal levels page to see if your modem finally has all four US channels running at levels less than +51 dBmV.  That's the goal for this round!