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T3 timeouts, Dynamic Range Violation Errors

adi7
New Poster

T3 timeouts, Dynamic Range Violation Errors

Issue began 4 days ago, internet connectivity on the modem is intermittent and gets worse later in the day (9PM - 1AM). Modem logs show T3 time-outs ("No Ranging Response received - T3 time-out") and Dynamic Range Violation Errors.

 

Basic troubleshooting completed. Checked the physical line and connection to my house, no damage.

 

Frequency Tables from modem (Netgear CM1200):

Startup Procedure
Procedure Status Comment
Acquire Downstream Channel 615000000 Hz Locked
Connectivity State OK Operational
Boot State OK Operational
Security Enabled BPI+
IP Provisioning Mode Honor MDD honorMdd(4)
 
Downstream Bonded Channels (Partial Service)
Channel Lock Status Modulation Channel ID Frequency Power SNR Correctables Uncorrectables
1 Locked QAM256 25 615000000 Hz 4.1 dBmV 40 dB 0 0
2 Locked QAM256 1 459000000 Hz 3.3 dBmV 40 dB 275 854
3 Locked QAM256 2 465000000 Hz 4 dBmV 40 dB 343 863
4 Locked QAM256 3 471000000 Hz 4 dBmV 40.2 dB 350 831
5 Locked QAM256 4 477000000 Hz 3.5 dBmV 40.2 dB 367 813
6 Locked QAM256 5 483000000 Hz 2.8 dBmV 39.5 dB 458 796
7 Locked QAM256 6 489000000 Hz 2.6 dBmV 39.7 dB 722 827
8 Locked QAM256 7 495000000 Hz 2.3 dBmV 39.5 dB 956 842
9 Locked QAM256 8 507000000 Hz 3.9 dBmV 40.2 dB 547 842
10 Locked QAM256 9 513000000 Hz 4.6 dBmV 40.1 dB 312 799
11 Locked QAM256 10 519000000 Hz 4.1 dBmV 40.1 dB 263 740
12 Locked QAM256 11 525000000 Hz 2.8 dBmV 39.2 dB 266 730
13 Locked QAM256 12 531000000 Hz 2.3 dBmV 38.5 dB 5918 4231
14 Locked QAM256 13 543000000 Hz 2.7 dBmV 39.8 dB 179 699
15 Locked QAM256 14 549000000 Hz 3.6 dBmV 40 dB 225 665
16 Locked QAM256 15 555000000 Hz 4.1 dBmV 40 dB 204 684
17 Locked QAM256 16 561000000 Hz 3.9 dBmV 40 dB 208 680
18 Locked QAM256 17 567000000 Hz 3.4 dBmV 38.9 dB 202 732
19 Locked QAM256 18 573000000 Hz 2.6 dBmV 39.5 dB 199 721
20 Locked QAM256 19 579000000 Hz 2.2 dBmV 39.8 dB 188 752
21 Locked QAM256 20 585000000 Hz 2.4 dBmV 31.2 dB 2934491 43643
22 Locked QAM256 21 591000000 Hz 3.1 dBmV 33.7 dB 7705 0
23 Locked QAM256 22 597000000 Hz 4 dBmV 38.6 dB 207 727
24 Locked QAM256 23 603000000 Hz 4.7 dBmV 38.4 dB 201 724
25 Locked QAM256 24 609000000 Hz 4.4 dBmV 39.1 dB 222 715
26 Locked QAM256 26 621000000 Hz 3.5 dBmV 39.8 dB 183 732
27 Locked QAM256 27 627000000 Hz 3 dBmV 39.7 dB 198 687
28 Locked QAM256 28 633000000 Hz 3.1 dBmV 39.7 dB 209 690
29 Locked QAM256 29 639000000 Hz 3.4 dBmV 39.7 dB 216 706
30 Locked QAM256 30 645000000 Hz 3.6 dBmV 39.7 dB 221 671
31 Locked QAM256 31 651000000 Hz 4.2 dBmV 39.8 dB 188 688
32 Locked QAM256 32 657000000 Hz 4.6 dBmV 39.9 dB 202 646
 
Upstream Bonded Channels (Partial Service)
Channel Lock Status US Channel Type Channel ID Symbol Rate Frequency Power
1 Not Locked Unknown 1 0 Ksym/sec 23700000 Hz 0.0 dBmV
2 Not Locked Unknown 2 0 Ksym/sec 17300000 Hz 0.0 dBmV
3 Not Locked Unknown 3 0 Ksym/sec 30100000 Hz 0.0 dBmV
4 Not Locked Unknown 4 0 Ksym/sec 36500000 Hz 0.0 dBmV
5 Locked ATDMA 5 1280 Ksym/sec 41200000 Hz 51.5 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
 
Downstream OFDM Channels
Channel Lock
Status
Modulation /
Profile ID
Channel
ID
Frequency Power SNR /
MER
Active Subcarrier
Number Range
Unerrored
Codewords
Correctable
Codewords
Uncorrectable
Codewords
1 Not Locked 0 0 0 Hz 0 dBmV 0.0 dB 0 ~ 4095 0 0 0
2 Not Locked 0 0 0 Hz 0 dBmV 0.0 dB 0 ~ 4095 0 0 0
 
Upstream OFDMA Channels
Channel Lock Status Modulation / Profile ID Channel ID Frequency Power
1 Not Locked 0 0 0 Hz 0 dBmV
2 Not Locked 0 0 0 Hz 0 dBmV
 
Extended Upstream Transmit Power
Enable Extended Upstream Transmit Power
 
Current System Time:Mon May 25 12:55:04 2020
System Up Time:00:56:25

 

EG
Expert

Re: T3 timeouts, Dynamic Range Violation Errors

The upstream power is too high and it may be intermittently fluctuating even higher to out of spec levels. That can cause random disconnects, spontaneous re-booting of the modem, speed, packet loss, latency problems, and the un-bonding of the multiple upstream channels (there should be 3-5. You only have 1). 

In a self troubleshooting 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 5-1002 MHz, bi-directional, and no gold colored garbage types like GE, RadioShack, RCA, Philips, Leviton, Magnavox, and Rocketfish from big box stores like Home Depot, Lowes, Target, Wal-Mart etc. Splitters should be swapped with known to be good / new ones to test

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.



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