S33 v2 with Xfinitiy very slow speeds of a sudden

Question

Been using the S33 for about a year with no problem. For the past month or so speeds have dropped to 11-12 download and upload. Status screen looks ok except for Downstream bonded Channels which are all in the -=5-7 DBmV range which I gather is high. Xfinity checked wiring outside and in and claims there’s no problem with their equipment. Partial event log follows. Is my modem toast? Is it really reaching back to 1969? Any advice appreciated.

31/12/1969 19:00:20	3	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=(Edited private information);CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 19:00:22	3	CMSTATUS:US_Diplexer_Mode_Change:TLV-9, 5-42MHz.
31/12/1969 19:00:25	3	No Ranging Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 19:00:40	3	CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
31/12/1969 19:00:40	3	CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
31/12/1969 19:00:40	3	CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
18/11/2025 14:07:51	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:08:01	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:08:01	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:08:01	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:08:15	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:08:28	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:08:34	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:08:38	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:08:40	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:08:40	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:08:44	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:08:47	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:08:49	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:08:52	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information)1;CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:08:52	3	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:08:52	3	16 consecutive T3 timeouts while trying to range on upstream channel 0;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:09:04	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:09:04	3	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:09:04	3	16 consecutive T3 timeouts while trying to range on upstream channel 4;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:09:09	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:09:10	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:09:13	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:09:14	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:09:15	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:09:19	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:09:24	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:09:28	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:09:41	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:09:41	3	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:09:41	3	16 consecutive T3 timeouts while trying to range on upstream channel 3;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:09:49	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:10:01	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:10:17	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:10:17	3	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:10:17	3	16 consecutive T3 timeouts while trying to range on upstream channel 2;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:10:29	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:10:53	3	Started Unicast Maintenance Ranging - No Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:10:53	3	Unicast Maintenance Ranging attempted - No response - Retries exhausted;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
18/11/2025 14:10:53	3	16 consecutive T3 timeouts while trying to range on upstream channel 1;CM-MAC=(Edited private information)1;CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 19:00:15	3	CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.
31/12/1969 19:00:19	3	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=(Edited private information);CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 19:00:23	3	CMSTATUS:US_Diplexer_Mode_Change:TLV-9, 5-42MHz.
31/12/1969 19:00:26	3	No Ranging Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 19:00:40	3	CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
31/12/1969 19:00:40	3	CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
31/12/1969 19:00:40	3	CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
31/12/1969 19:00:16	3	CMSTATUS:US_Diplexer_Mode_Change:Init, 5-42MHz.
31/12/1969 19:00:20	3	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=(Edited private information);CMTS-MAC=00:00:00:00:00:00;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 19:00:21	3	CMSTATUS:US_Diplexer_Mode_Change:TLV-9, 5-42MHz.
31/12/1969 19:00:24	3	No Ranging Response received - T3 time-out;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
31/12/1969 19:00:36	3	CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.2, 108MHz.
31/12/1969 19:00:36	3	CMSTATUS:DS_Diplexer_Mode_Change_Ignored:TLV-84.3, 1002MHz.
31/12/1969 19:00:36	3	CMSTATUS:US_Diplexer_Mode_Change:TLV-84.1, 5-42MHz.
19/11/2025 09:11:54	3	Successful LAN WebGUI login from 73.147.132.47 on 25/11/19 at 9:11 AM.
19/11/2025 14:11:03	3	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
19/11/2025 14:11:09	3	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;
19/11/2025 14:12:52	3	SYNC Timing Synchronization failure - Failed to acquire QAM/QPSK symbol timing;;CM-MAC=(Edited private information);CMTS-MAC=00:01:5c:b2:16:6b;CM-QOS=1.1;CM-VER=3.1;

plemans · Answer

Your logs indicate there is still an issue. Problem is xfinity is great at saying there’s not. And it might actually be the modem. I’m not telling you what to do, but I’ve had to rent a modem from them for a month to prove it was their line. Or it might prove its not and it is a bad modem. You’re a little stuck if they’ve already checked the line.

Sign up

Login to the community

Scanning file for viruses.

This file cannot be downloaded