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[Cable] DCM 476 Random Disconnects - Calling all Cable Modem Gur

downloadmodem_log.txt 7,719 bytes
no connection
downloadmodem_log_co···shed.txt 5,110 bytes
connection established
Respected Members,

I've been reading the forum regarding issues with the thomson dcm 476 modems; to date, all posts are related to outdated firmware causing issues with cable disconnects.

I've checked my firmware version on the diagnostic page and i believe it to be current. However, i am still continuing to experience random disconnects.

I find that the modem will at random disconnect from the internet throughout the entire day. At times it will be inactive for 5 to 10 minutes and at others it will be come for hours.

The last time i called in, the technical support member had me change the wiring to the cable modem to have the modem reconnect. I now feel that it was purely coincidental that the modem had come online at that time. I've since then tried to change the cable several times to no avail - these are cables i know work because i used them for tv.

I'm not sure if i qualify for warranty any more as i switch to TekSavvy back in March.

I would really appreciate any help with this.


Attached please find the states the modem goes through during disconnects.



Re: [Cable] DCM 476 Random Disconnects - Calling all Cable Modem

the return / upload power is high, when these modems have to use higher power levels they can get hot

also check your cable type, you want to be using one nice piece of rg6


·Start Communicat..
·TekSavvy Cable
reply to aussie_r
Your downstream power is fine, even great. Your upstream, however is being asked to transmit 57dBmV, much higher than the typical max of ~53dBmV. There's your problem right there - the CMTS can barely hear your modem.

So what can be done to remedy the problem?
1. Can you reduce the amount of cable/number of splitters between your modem and the point where the modem enters your building? Often you can see improvements of a few dB there. Make sure none of your cables/splitters are a problem by removing them and observing the signal level change on the modem.

2. If #1 does not solve your problem, post in direct with your signal levels and get TSI to have Rogers to come fix the line to your building.

You're the second person posting with these exact symptoms - »[Cable] Sloooow connection in Barrhaven on Fallowfield POI


London, ON
reply to aussie_r
So if my upstream power on the 4 channels are 46,46,46,49, would be decent enough to go with a DCM 476? SB6120 owner here looking to upgrade but being careful not to make things worse!


Nepean, ON
Yeah, no problem with that.
And any cable line on which there is an issue is an "out of spec cable line" (aka. "RF issue") that can usually be fixed by rearranging splitters or having a Rogers tech visit and fix something outside.


reply to aussie_r
DennisLX and nbinont, thank you both for your help!

I went to the basement and surely enough there was a splitter in place.
I removed the splitter and connected my modem directly to the line from outside and the modem came online.

I am going to monitor the connection over the course of this week and advise you if anything changes.

Thanks again!


downloadmodem_log_2.txt 4,269 bytes
diagnostic log
Sorry, before i claim success, i thought i'd upload the latest diagnostic log for review.

Thanks in advance,

TSI Support1
TSI Support
Chatham, ON
reply to aussie_r
Hello Aussie,

I am glad that our wonderful regulars on DSLr were able to help you identify and fix the issue. Do make sure to check it over the next week, and if the issue comes back, please post in the »TekSavvy Direct so we can look further into this for you.

Thank you again for being a Teksavvy Customer!

TSI - Scott
TSI Support - TekSavvy Solutions Inc.
Authorized TSI employee ( »TekSavvy FAQ »Official support in the forum )


reply to aussie_r
Nice improvement! Upstream is now within spec, but relatively close to the limit. If it's stable, you're good to go, if not stable you'll have to do #2. Good luck!


Cambridge, ON
reply to aussie_r
And you have 4 upstream channels bonded (albeit at high transmit power) rather than one at impossibly high transmit power, which means the CMTS can finally hear the modem. But just barely...

Still, it's an improvement.


Bolton, ON
reply to aussie_r
if still having issues and before tsi calls rogers tech, see if you can connect the modem closer to the demark if not directly at the demark, if the stats are better then it could be internal house wiring problem