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prashanth12's avatar
prashanth12
Follower
Sep 17, 2022

C7000V2 intermittent lost connection

I'm using a C7000v2 Netgear modem and router, and I have been using it for three years without a problem but all of sudden last two days, I had an issue with the internet connection, which is frequently dropping, the modem itself rebooting and then connected for 10 mins or 1 hr. or couple of hours then it self rebooting again. It happened 10-15 times a day, which was frustrating.

I tried to power out/reset/factory reset the modem; even I changed MTU size on my router, non of them are helping me. I directly plugged power/router connected to the wall port and checked all cable connections; those are good, with no rust, no breaks, and brand-new cables.

 

I also read some blogs on a similar issue in this community, but none of them had confirmed it was fixed permanently.

Any input would be appreciated.

 

My router firmware version: V1.03.08

Any inputs appreciated.

AC1900 WiFi Cable Modem Router (C7000) V2

 

 

1970-1-1, 00:00:39Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
2022-9-17, 14:20:31Critical (3)Started Unicast Maintenance Ranging - No Response received - T3 time-out; CM-MAC=CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:90:f0:44:00:00;CM-QOS=1.1;CM-VER=3.0;
1970-1-1, 00:00:39Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:39Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=CM-MAC=X:X:X:X:X:X8;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:37Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:39Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:39Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:37Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:37Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:37Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:37Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:37Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:37Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:38Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:37Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:01:24Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:01:12Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:01:11Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:01:01Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=X:X:X:X:X:X;;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:01:00Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:42Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=X:X:X:X:X:X;;CM-MAC=X:X:X:X:X:X;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:39Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:01:22Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:01:10Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:01:10Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing;CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:59Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:58Critical (3)SYNC Timing Synchronization failure - Failed to acquire FEC framing; CM-MAC=X:X:X:X:X:X;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:40Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=X:X:X:X:X:X;;CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
1970-1-1, 00:00:37Critical (3)SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=X:X:X:X:X:XCMTS-MAC=00:00:00:00:00:00;CM-QOS=1.0;CM-VER=3.0;
   
   
   

 

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

417000000 Hz

Locked

Connectivity State

OK

Operational

Boot State

OK

Operational

Security

Enabled

BPI+

IP Provisioning Mode

Honor MDD

honorMdd(4)

 

Downstream Bonded Channels

Channel

Lock Status

Modulation

Channel ID

Frequency

Power

SNR

Correctables

Uncorrectables

1

Locked

QAM256

4

417000000 Hz

5.3 dBmV

40.4 dB

0

0

2

Locked

QAM256

1

399000000 Hz

5.3 dBmV

39.8 dB

0

0

3

Locked

QAM256

2

405000000 Hz

5.2 dBmV

40.7 dB

0

0

4

Locked

QAM256

3

411000000 Hz

5.2 dBmV

40.3 dB

0

0

5

Locked

QAM256

5

423000000 Hz

5.1 dBmV

40 dB

0

0

6

Locked

QAM256

6

435000000 Hz

5.2 dBmV

39.9 dB

0

0

7

Locked

QAM256

7

441000000 Hz

5.2 dBmV

39.8 dB

0

0

8

Locked

QAM256

8

447000000 Hz

5.4 dBmV

40 dB

0

0

9

Locked

QAM256

9

453000000 Hz

5.5 dBmV

40.1 dB

0

0

10

Locked

QAM256

10

459000000 Hz

5.5 dBmV

40.3 dB

0

0

11

Locked

QAM256

11

465000000 Hz

5.6 dBmV

40.7 dB

0

0

12

Locked

QAM256

12

471000000 Hz

5.7 dBmV

41.1 dB

0

0

13

Locked

QAM256

13

477000000 Hz

5.9 dBmV

41.5 dB

0

0

14

Locked

QAM256

14

483000000 Hz

5.8 dBmV

41.5 dB

0

0

15

Locked

QAM256

15

489000000 Hz

5.9 dBmV

41.5 dB

0

0

16

Locked

QAM256

16

495000000 Hz

6 dBmV

41.2 dB

0

0

17

Locked

QAM256

17

507000000 Hz

5.6 dBmV

40.3 dB

0

0

18

Locked

QAM256

18

513000000 Hz

5.7 dBmV

40.3 dB

0

0

19

Locked

QAM256

19

519000000 Hz

5.7 dBmV

40.3 dB

0

0

20

Locked

QAM256

20

525000000 Hz

5.7 dBmV

40.3 dB

0

0

21

Locked

QAM256

21

531000000 Hz

5.9 dBmV

40.4 dB

0

0

22

Locked

QAM256

22

537000000 Hz

5.8 dBmV

40.4 dB

0

0

23

Locked

QAM256

23

543000000 Hz

5.7 dBmV

40.8 dB

0

0

24

Locked

QAM256

24

549000000 Hz

5.8 dBmV

40.8 dB

0

0

 

Upstream Bonded Channels

Channel

Lock Status

US Channel Type

Channel ID

Symbol Rate

Frequency

Power

1

Locked

ATDMA

1

5120 Ksym/sec

35600000 Hz

35 dBmV

2

Locked

ATDMA

2

5120 Ksym/sec

29200000 Hz

34.8 dBmV

3

Locked

ATDMA

3

5120 Ksym/sec

22800000 Hz

34.2 dBmV

4

Locked

ATDMA

4

5120 Ksym/sec

16400000 Hz

34.3 dBmV

5

Locked

ATDMA

5

1280 Ksym/sec

39600000 Hz

30.6 dBmV

6

Not Locked

Unknown

0

0 Ksym/sec

0 Hz

0.0 dBmV

7

Not Locked

Unknown

0

0 Ksym/sec

0 Hz

0.0 dBmV

8

Not Locked

Unknown

0

0 Ksym/sec

0 Hz

0.0 dBmV

 

 

1 Reply

  • plemans's avatar
    plemans
    Guru - Experienced User
    Sep 18, 2022

    You're getting line issues from the looks of the log. 

    Start with removing any amplifiers, signal attenuators, or splitters from the coax.
    From there check the line for kinks, damage, moisture in the line.
    Check the connectors for improperly made ends, foil touching the copper coax line, loose connections, bad/old/cheap connectors, or corroded connections. Replace them if you do.
    If you can, simply connect the modem right where the coax comes into the home. This prevents wiring in the home from being the issue. And some ISP’s charge if the wiring issue is in the home. So this helps prevent this.

    If that doesn't help, the isp needs to check the line