CM700 dropping internet connection

[vdot]

Lately, the modem seems to drop internet connection at random. I noticed some errors in the event log of the modem coincident with a recent dropped connection.

Sep 18 2019 12:06:59 Critical (3) Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out
Sep 18 2019 12:07:40 Warning (5) MIMO Event MIMO: Stored MIMO=-1 post cfg file MIMO=-1
Sep 18 2019 14:13:25 Critical (3) No Ranging Response received - T3 time-out

This same pattern seems to have occurred a few more times in the log although I cannot confirm they all coincided with a drop. Does anyone recognize these errors and can tell the suspected source of the problem?

[plemans · Accepted solution]

did you reboot your modem? you have a lot of uncorrectables.

If you reboot, it resets it so you can go off the new settings. 

here's an article that goes over signal strengths, snr, logs, etc. Its not to long but has good info and is easier than me typing it all up. 

https://www.howtogeek.com/240575/how-to-read-your-cable-modems-diagnostic-page-when-something-goes-w...

[plemans]

If you look at your connections page, whats it look like? aka take a screen snip of your upload/download connections and post on here. 

A lot of errors/drops with modems can be traced back to poor connections/cables/splitters/etc.

I recommend this.

1. Remove any splitters possible. (if you need 1 to split off for cable, remove it for testing and you can put it back in later)

2. Check all your connections.  A loose connection or correded connection can cause errors. Also cheap connectors can do it as well.

3. inspect your cable for kinks (shouldn't be any), corrosion, or potential water damage. 

4. remove any amplifiers or anything else in line.

5. I'd recommend moving the modem to right where the coax comes into the house and testing it at this point. reduces the chances of it being something in line. 

if you're still getting errors after this, I'd check with your isp to have them inspect your line. They're responsible for it until it enters your house and then its on you. 

[FURRYe38]

Have the ISP check the signal and line quality UP to the modem and check there logs as well. 

Be sure your using good RG6 coax cabling, not RG59. 

[vdot]

Based your response and that of FURRYe38, I called my ISP and had them check the signal strength at the modem (I guess I could have looked at the connections page on the router, but didn't know how to read the entries). Sure enough, it was weak. Traced it to a 4-way splitter in the basement that my previous homeowner had installed. Didn't need that splitter any way, so used an inline coupler and the problem seems to have gone away. I do have the connections table uploaded, but it probably shows things are mighty fine now. Would like some guidance on what to expect in Power and SNR columns for a good connection.

[plemans · Accepted solution]

did you reboot your modem? you have a lot of uncorrectables.

If you reboot, it resets it so you can go off the new settings. 

here's an article that goes over signal strengths, snr, logs, etc. Its not to long but has good info and is easier than me typing it all up. 

https://www.howtogeek.com/240575/how-to-read-your-cable-modems-diagnostic-page-when-something-goes-w...

[FURRYe38]

Glad it was a splitter issue and was an easy fix. 

Enjoy. 

[vdot]

Thanks. Rebooted and the uncorrectables are cleared to 0. Summer correctable errors do show up in a couple of channels, but the numbers, below 10, seem stable. Also, thanks for the article on how to read the log entries. Very useful!