Modem keeps restarting randomly

[Numenization]

For the past two years, my modem (Arris TM722g) has been randomly restarting, causing my network to go down for the time it takes for it to boot. Most of the time its fine, but maybe every three months or so it will happen for 2-3 weeks constantly. This is very hindering since I play online games such as League of Legends and Guild Wars 2.

I'm not 100% sure on my exact setup, but I think that the cable splits off into two paths: one that goes to the modem, and one that goes off to all the TVs. When the modem restarts the TVs are unaffected, so I'm pretty sure its an issue with the modem. My ISP is comcast, and when I get these outages my friends (who live no more than 5 doors down and have the same ISP/plan) are unaffected, so I don't think its the ISP having outages in the area.

I've considered buying another modem, but not many other modems have a phone jack, which is necessary because I use my landline.

I haven't observed any possible cause to the resets. It doesn't go down under load or anything. I don't use any VPNs or anything. I just don't know what could be causing this, or how to fix it. The only possible thing I could think of is a heating issue? It's bunched up in a cabinet with a PC that gets moderate use and the router. But I can't see how that could cause enough heat for it to force reboot...

 

[Kewlx25]

If you can log into your modem, it may have a log of all events.

 

[i7Baby]

If the modem isn't too old, then put it in for a warranty return.

Else just replace it with eg http://www.newegg.com/Product/Product.aspx?Item=N82E16825124009

 

[Numenization]

If you can log into your modem, it may have a log of all events.

Many repeating instancess of:

5/7/2015 14:12 82000200 3 No Ranging Response received - T3 time-out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;

then....

5/7/2015 15:08 82000400 3 Received Response to Broadcast Maintenance Request, But no Unicast Maintenance opportunities received - T4 time out;CM-MAC=**:**:**:**:**:**;CMTS-MAC=**:**:**:**:**:**;CM-QOS=1.1;CM-VER=3.0;


From what I see it stops receiving signals within its range (?) and then picks back up (with a reboot...) when it can find a signal again. How can I go about fixing that? I don't seem to have access to the advanced config tab of my modem's ui. It also seems to be using DOCSIS 2.0 as opposed to 3.0 (as indicated by looking at the upstream statistics), which I'm pretty sure the modem is 3.0 compatible.

Heres my upstream/downstream info if that helps.

Downstream:
http://gyazo.com/04149a8192cf60428ce9f18b87cf11c6

Upstream:
http://gyazo.com/8506e972b8edacd37ce86e9b32b9340b

 

[Numenization]

So looking around on the internet I've came to the conclusion that the outages are most likely caused by weak upstream and downstream power levels. I figure that a fix for this would be buying a cable signal amplifier ( http://www.amazon.com/Motorola-Signal-Booster-1-Port-Amplifier/dp/B003T2RY7I/ref=pd_sxp_grid_pt_0_1 ). Any second opinions or confirmations would be appreciated before buying this.

 

[i7Baby]

As I said - try another modem.