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Intermittent Connectivity - T3 timeout and SYNC Timing Sync Failure fail to acquire QAM/QPSK symbol

Regular Visitor

Intermittent Connectivity - T3 timeout and SYNC Timing Sync Failure fail to acquire QAM/QPSK symbol

For what seems like almost 1 year, I have had intermittent connectivity issues mostly with T3 and T4 timeouts.  I sometimes work from home and this situation has gotten worse, which is a deal-breaker for me.  I have had it and am about ready to switch to AT&T Fiber, which is now available in my area.  I have been a Comcast/Xifinity internet customer since 1995 and have never had problems like this (hence my longevity as a customer).  I have to restart my modem several times per day.  I have had a tech out who checked everything from the top of the pole to the inside of the house and replaced lines and connectors.  I have called a number of times with no success in resolving the problem.

 

I have an ArrisSB8200 modem.   Technical info is below.  Help!!   Can this issue be fixed or do I need to jump ship?  

 

Event Log (most recent):  Yes, there seems to be a definite pattern.

 

6-14-2018, 15:6:56 Critical(3) "Started Unicast Maintenance Ranging - No Response received - T3 time-out;"
1-1-1970, 0:0:40 Notice(6) "Honoring MDD; IP provisioning mode = IPv6"
1-1-1970, 0:0:37 Critical(3) "No Ranging Response received - T3 time-out"
1-1-1970, 0:0:33 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;"
6-14-2018, 13:13:29 Critical(3) "Started Unicast Maintenance Ranging - No Response received - T3 time-out;"
1-1-1970, 0:0:37 Critical(3) "No Ranging Response received - T3 time-out;"
1-1-1970, 0:0:33 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;"
6-14-2018, 7:53:56 Critical(3) "Started Unicast Maintenance Ranging - No Response received - T3 time-out"
1-1-1970, 0:0:39 Critical(3) "No Ranging Response received - T3 time-out"
1-1-1970, 0:0:33 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;"
6-13-2018, 20:25:47 Critical(3) "Started Unicast Maintenance Ranging - No Response received - T3 time-out;"
1-1-1970, 0:0:37 Critical(3) "No Ranging Response received - T3 time-out;"
1-1-1970, 0:0:33 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;"
6-13-2018, 16:13:2 Critical(3) "Started Unicast Maintenance Ranging - No Response received - T3 time-out;"
1-1-1970, 0:0:37 Critical(3) "No Ranging Response received - T3 time-out;"
1-1-1970, 0:0:33 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;"
6-13-2018, 13:28:0 Critical(3) "Started Unicast Maintenance Ranging - No Response received - T3 time-out;"
1-1-1970, 0:0:37 Critical(3) "No Ranging Response received - T3 time-out;"
1-1-1970, 0:0:33 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;"
6-12-2018, 10:16:33 Critical(3) "Started Unicast Maintenance Ranging - No Response received - T3 time-out;"
1-1-1970, 0:0:39 Critical(3) "No Ranging Response received - T3 time-out;"
1-1-1970, 0:0:33 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;"
6-11-2018, 23:25:20 Critical(3) "Started Unicast Maintenance Ranging - No Response received - T3 time-out;"
1-1-1970, 0:0:38 Critical(3) "No Ranging Response received - T3 time-out;"
1-1-1970, 0:0:33 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;"
6-7-2018, 10:52:49 Critical(3) "Started Unicast Maintenance Ranging - No Response received - T3 time-out;"
1-1-1970, 0:0:39 Critical(3) "No Ranging Response received - T3 time-out;"
1-1-1970, 0:0:33 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;"
6-6-2018, 10:54:12 Critical(3) "Started Unicast Maintenance Ranging - No Response received - T3 time-out;"
1-1-1970, 0:0:46 Critical(3) "No Ranging Response received - T3 time-out;"
1-1-1970, 0:0:33 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;"
5-27-2018, 11:17:31 Critical(3) "Started Unicast Maintenance Ranging - No Response received - T3 time-out;"
1-1-1970, 0:0:39 Critical(3) "No Ranging Response received - T3 time-out;
1-1-1970, 0:0:33 Critical(3) "SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;"
5-27-2018, 10:24:11 Critical(3) "Started Unicast Maintenance Ranging - No Response received - T3 time-out;"

 

Current signal levels are as follows:

 

Downstream Bonded Channels
Channel ID Lock Status Modulation Frequency Power SNR/MER Corrected Uncorrectables
26 Locked QAM256 639000000 Hz 5.1 dBmV 40.4 dB 0 0
1 Locked QAM256 489000000 Hz 6.9 dBmV 41.1 dB 0 0
2 Locked QAM256 495000000 Hz 7.1 dBmV 41.1 dB 0 0
3 Locked QAM256 501000000 Hz 7.2 dBmV 41.0 dB 0 0
4 Locked QAM256 507000000 Hz 7.2 dBmV 41.0 dB 0 0
5 Locked QAM256 513000000 Hz 6.7 dBmV 40.8 dB 0 0
6 Locked QAM256 519000000 Hz 6.1 dBmV 40.7 dB 0 0
7 Locked QAM256 525000000 Hz 5.5 dBmV 40.6 dB 0 0
8 Locked QAM256 531000000 Hz 5.9 dBmV 40.8 dB 0 0
9 Locked QAM256 537000000 Hz 6.2 dBmV 40.7 dB 0 0
10 Locked QAM256 543000000 Hz 6.1 dBmV 40.7 dB 0 0
11 Locked QAM256 549000000 Hz 6.6 dBmV 41.1 dB 0 0
12 Locked QAM256 555000000 Hz 6.9 dBmV 41.1 dB 0 0
13 Locked QAM256 561000000 Hz 7.1 dBmV 41.0 dB 0 0
14 Locked QAM256 567000000 Hz 7.0 dBmV 41.0 dB 0 0
15 Locked QAM256 573000000 Hz 6.4 dBmV 40.8 dB 0 0
16 Locked QAM256 579000000 Hz 5.9 dBmV 40.7 dB 0 0
17 Locked QAM256 585000000 Hz 5.5 dBmV 40.5 dB 0 0
18 Locked QAM256 591000000 Hz 5.3 dBmV 40.5 dB 0 0
19 Locked QAM256 597000000 Hz 5.3 dBmV 40.3 dB 0 0
20 Locked QAM256 603000000 Hz 5.8 dBmV 40.5 dB 0 0
21 Locked QAM256 609000000 Hz 5.8 dBmV 40.6 dB 0 0
22 Locked QAM256 615000000 Hz 5.5 dBmV 40.3 dB 0 0
23 Locked QAM256 621000000 Hz 5.2 dBmV 40.2 dB 0 0
24 Locked QAM256 627000000 Hz 5.2 dBmV 40.3 dB 0 0
25 Locked QAM256 633000000 Hz 5.3 dBmV 40.4 dB 0 0
27 Locked QAM256 645000000 Hz 4.8 dBmV 40.2 dB 0 0
28 Locked QAM256 651000000 Hz 4.3 dBmV 40.0 dB 0 0
29 Locked QAM256 657000000 Hz 3.7 dBmV 39.6 dB 0 0
30 Locked QAM256 663000000 Hz 3.5 dBmV 39.5 dB 0 0
31 Locked QAM256 669000000 Hz 3.4 dBmV 39.5 dB 0 0
33 Locked Other 732000000 Hz 3.7 dBmV 37.5 dB 911833 0

 

 
Upstream Bonded Channels
Channel Channel ID Lock Status US Channel Type Frequency Width Power
1 4 Locked SC-QAM 16500000 Hz 6400000 Hz 40.5 dBmV
2 2 Locked SC-QAM 29600000 Hz 6400000 Hz 39.5 dBmV
3 3 Locked SC-QAM 23000000 Hz 6400000 Hz 40.3 dBmV
4 1 Locked SC-QAM 36100000 Hz 6400000 Hz

38.5 dBmV

 

 

Expert

Re: Intermittent Connectivity - T3 timeout and SYNC Timing Sync Failure fail to acquire QAM/QPSK sym

Hi @gumbAA,

Your power levels look fine. I'd say the next step is to rent a modem temporarily from Comcast to eliminate the possibility of your modem being defective. 

 

I've asked an employee to check the CMTS for real-time and historical RF signal reports from your modem. They can also check your local node/plant for any degradation or error reports. You can expect a reply in this thread. 



"Keepin' it clean since '09"
I am not a Comcast employee, just a moderator.
Official Employee

Re: Intermittent Connectivity - T3 timeout and SYNC Timing Sync Failure fail to acquire QAM/QPSK ...

Hello gumbAA, I can look into your signals and equipment health on my end. Can you please send me a private message with your full name, street address, and account number by clicking on my name (ComcastAmir) and then "private message me"?

Regular Visitor

Re: Intermittent Connectivity - T3 timeout and SYNC Timing Sync Failure fail to acquire QAM/QPSK ...

Thanks very much, ComcastAmir.  PM'ing you right now.

Regular Visitor

Re: Intermittent Connectivity - T3 timeout and SYNC Timing Sync Failure fail to acquire QAM/QPSK ...

I sent you a PM - do you have any information or assistance for me? I have been trying to work from home today and the Internet connectivity issue is making it impossible. I’m having to use my internet hotspot through my phone. As I said in my original post, I have been an internet customer since 1995, but I cannot continue to be one if the internet service no longer functions. This is unacceptable.
Regular Visitor

Re: Intermittent Connectivity - T3 timeout and SYNC Timing Sync Failure fail to acquire QAM/QPSK ...

Hello?  Anyone?   Haven't heard back from ComcastAmir.  Still having all the same problems.

Official Employee

Re: Intermittent Connectivity - T3 timeout and SYNC Timing Sync Failure fail to acquire QAM/QPSK ...

gumbAA wrote: Hello?  Anyone?   Haven't heard back from ComcastAmir.  Still having all the same problems.

 

I replied to you PM, please reach back out to me there for further assistance.