I just got a CBR750 second hand and am having trouble connecting to RCN. When the router boots up it gets to the final "online" light flashing but that light never turns solid. I've noticed the light below is a neon purple as well. I'm able to connect to the admin app via ethernet and wifi, but the unit will not connect to the internet. In the cable connection section of the app it just says "Modem is offline. Please check RF connection." Any help troubleshooting this issue would be greatly appreciated!

Thanks for the help. RCN had to send a technician out and he said the power levels were a little high (~12 [dBmV I assume]). He was able to get it working, though.

CBR750 not connecting to RCN | NETGEAR Communities

5 Replies

FURRYe38

Guru

Nov 11, 2021

Please post a copy and paste of the modems connection status page.

Have the ISP check the signal and line quality UP to the modem. Be sure the ISP provisions the modem correctly.
Be sure there are no coax cable line splitters in the between the modem and ISP service box.
Be sure your using good quality RG6 coax cable up to the modem.
Be sure to power OFF the modem for 1 minute then back ON.
https://community.netgear.com/t5/Cable-Modems-Routers/General-info-and-Troubleshooting-for-Cable-Modems/m-p/1530376#M12853

pbert

Aspirant

Nov 11, 2021

Thanks for the reply. The coax cable does have a splitter right before connecting to the service box. If I can't get it working otherwise, do you think a female to female adapter would be OK or does it need to be one cable from the service box to the modem? We do not use the other cable running from the splitter it can definitely be removed.

I tried a full power off and power up cycle a few times, but still no solid online light. I also tried upgrading to the latest firmware (4.6.5.8).

Is this the connection status you were referring to?

Spoiler

Startup Procedure

Procedure	Status	Comment
Acquire Downstream Channel	363000000 Hz	Locked
Connectivity State	In Progress	Not Synchronized
Boot State	In Progress	Unknown
Security	Disabled	Disabled
IP Provisioning Mode	In Progress	Unknown

Downstream Bonded Channels

Channel	Lock Status	Modulation	Channel ID	Frequency	Power	SNR	Correctables	Uncorrectable
1	Locked	QAM 256	17	363000000 Hz	7.5 dBmV	40.9 dB	0	0
2	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
3	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
4	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
5	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
6	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
7	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
8	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
9	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
10	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
11	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
12	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
13	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
14	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
15	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
16	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
17	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
18	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
19	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
20	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
21	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
22	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
23	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
24	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
25	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
26	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
27	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
28	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
29	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
30	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
31	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0
32	Not Locked	N/A	N/A	0 Hz	0.0 dBmV	0.0 dB	0	0

Upstream Bonded Channels

Channel	Lock Status	US Channel Type	Channel ID	Symbol Rate	Frequency	Power
1	Locked	ATDMA	2	5120 Ksym/sec	30350000 Hz	40.5 dBmV
2	Not Locked	N/A	Unknown	0 Ksym/sec	0 Hz	0.0 dBmV
3	Not Locked	N/A	Unknown	0 Ksym/sec	0 Hz	0.0 dBmV
4	Not Locked	N/A	Unknown	0 Ksym/sec	0 Hz	0.0 dBmV
5	Not Locked	N/A	Unknown	0 Ksym/sec	0 Hz	0.0 dBmV
6	Not Locked	N/A	Unknown	0 Ksym/sec	0 Hz	0.0 dBmV
7	Not Locked	N/A	Unknown	0 Ksym/sec	0 Hz	0.0 dBmV
8	Not Locked	N/A	Unknown	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	0.0 dBmV	0.0 dB	0~4095	0	0	0
2	Not Locked	0	0	0 Hz	0.0 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	0.0 dBmV
2	Not Locked	0	0	0 Hz	0.0 dBmV

Current System Time: Thu Jan 1 00:11:02 1970System Up Time 00:10:58

Startup Procedure ProcedureStatusCommentAcquire Downstream Channel363000000 HzLockedConnectivity StateIn ProgressNot SynchronizedBoot StateIn ProgressUnknownSecurityDisabledDisabledIP Provisioning ModeIn ProgressUnknownDownstream Bonded Channels ChannelLock StatusModulationChannel IDFrequencyPowerSNRCorrectablesUncorrectable1LockedQAM 25617363000000 Hz7.5 dBmV40.9 dB002Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB003Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB004Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB005Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB006Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB007Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB008Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB009Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0010Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0011Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0012Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0013Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0014Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0015Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0016Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0017Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0018Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0019Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0020Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0021Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0022Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0023Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0024Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0025Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0026Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0027Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0028Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0029Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0030Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0031Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB0032Not LockedN/AN/A0 Hz0.0 dBmV0.0 dB00Upstream Bonded Channels ChannelLock StatusUS Channel TypeChannel IDSymbol RateFrequencyPower1LockedATDMA25120 Ksym/sec30350000 Hz40.5 dBmV2Not LockedN/AUnknown0 Ksym/sec0 Hz0.0 dBmV3Not LockedN/AUnknown0 Ksym/sec0 Hz0.0 dBmV4Not LockedN/AUnknown0 Ksym/sec0 Hz0.0 dBmV5Not LockedN/AUnknown0 Ksym/sec0 Hz0.0 dBmV6Not LockedN/AUnknown0 Ksym/sec0 Hz0.0 dBmV7Not LockedN/AUnknown0 Ksym/sec0 Hz0.0 dBmV8Not LockedN/AUnknown0 Ksym/sec0 Hz0.0 dBmVDownstream OFDM Channels ChannelLock StatusModulation/Profile IDChannel IDFrequencyPowerSNR/MERActive SubcarrierNumber RangeUnerroredCodewordsCorrectableCodewordsUncorrectableCodewords1Not Locked000 Hz0.0 dBmV0.0 dB0~40950002Not Locked000 Hz0.0 dBmV0.0 dB0~4095000Upstream OFDMA Channels ChannelLock StatusModulation/Profile IDChannel IDFrequencyPower1Not Locked000 Hz0.0 dBmV2Not Locked000 Hz0.0 dBmVCurrent System Time: Thu Jan 1 00:11:02 1970System Up Time 00:10:58

FURRYe38
Guru
Nov 11, 2021
Ya remove the splitter. A barrel connector can work.

Um, you only have 1 channel locked in for both UP and Down. There should be more channels locked in.

Power maybe high on the 1 channel.

You need to contact your ISP and have them check your line and check the connections status page on the CBR. You should have several Download Channels locked in.

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CBR750 not connecting to RCN