Cable Modem acting up

Hi,

The last couple of days my cable modem has randomly decided not to work. Obviously right now it is working. It'll sit there with the Power and Recieve light on and the Send light flashing as if it is trying to find something.

I have Windows XP SP1 with a Motorola Surfboard Cable Modem SB4200. I bought the cable modem in February 2003. I still have the receipt for it.

There is a router (Linksys Etherfast Cable/DSL Router with 4-port switch Model # BEFSR41

I ran Ad-Aware and Spybot S&D and didn't find anything.

I ran the ping test as suggested in another thread and the test comes back with the good values so the NIC is fine.

It also happened at the beginning of September for 4 days straight. It would not be working in the morning and then would work fine in the afteroon/night. I wonder if it could be a signal strength problem.

Any help would be appreciated and if anyone needs any more info to try to help, let me know!

Hopefully I'll be back later to see if anyone has any ideas and/or suggestions.

EDIT: It worked after I unscrewed the cable from the modem and put it back on. Maybe that helped? I would hate to think it was that simple.

 

Exactly what Tony said and I will add it could also be a splitter in line that isn't bi-directional.

 

Thanks for the responses guys.

My roomate, whose name is on the cable bill, is going to call Monday and see if they can come out here and test it for signal strength.

 

A lot of possibilities here. One being possible mis-matched hardware.

It would not be working in the morning and then would work fine in the afteroon/night

Sounds very familiar

I still have the same problem at times. I can go for days with no probems. Then all of the sudden several times a day.

Also at times the problem only effects the Windows XP Pro machiine. The two 98SE machines do not seem to be effected every time.

Also in the past I had a Motorola Modem connected to a Linksys BEFSR41 Router and the problem was on all machines then. I changed the Modem to a Linksys BEFCMU10 Modem and the problem then 90% disapeared.

Also making sure that all NICs were Linksys seemed to help.

Other times I have restarted Windows XP and the problem went away.

Could this in any way be involved. ?

I also see you have a router. So I take it for granted that you have more than one machine. Are both machines effected at the same time ?

BillyBob

 

The modem has been connected to the router for about a year to two years and it's only acted up in the last 6 weeks or so.

There's actually 3 computers on the router. When the modem is acting up, all 3 computers aren't able to access the Internet.

I hope it's something simple. I would hate to have to spend money to replace hardware.

 

That sounds very familiar.

Also it is possible that the modem may have been damaged by an electrical surge from lighting maybe. I think that is what realy hurt mine. Both my Modem and a TV.

If the above is indeed the case then you may well have no choice but to ignore your thoughts below and get a new Modem.

Also a thought just crossed my mind. ( what there is of it lately ) Do you have all three machines set to Auto obtain an address ?

BillyBob

 

I wonder if that could be it. I remember reading somewhere that a guy replaced just the power cord to it and it worked fine. I'll see if I can buy just that.

I didn't think of that. I'll check that later today and report back.

I rebooted the computer this morning and it didn't work.

I think I'm going to prepare myself for the fact that I'll need to buy a new cable modem. The one I currently have has basically been on for the last 2 1/2 years except for when I moved.

 

I used the reset button on the router. I don't know if it helped since the cable modem is still randomly going in and out.

How can I check the dhcp clients table to see if it is corrupt?

Hopefully, I'll be able to be back online later to check and see. I would Google it, but I have to go to work. Thanks in advance.

 

I really think it's the quality of the cable and terminations to your modem. Nothing you can fix unless you know how to terminate RG6 and have all the commercial tools to do so.
Poorly terminated cables will allow the signal to leak out causing the modem to drop in and out.

 

Basically, I should contact Comcast and have them send out a technician to come out, test the cables for signal strength, and replace them accordingly?

 

Yep,

That's where I would start.

 

My roomate STILL hasn't contacted Comcast.

However, I think I may have inadvertently found out what is causing the problem. I have a cable coming out from the wall to a splitter. One cable off of the splitter goes to my cable modeam (Duh!) and the other goes to my digital cable box that has a DVR. built into it.

Sunday night, I recorded the West Wing. Since the cable box is in my room and it is small, I decided to put the cable box out in the living room so that we could watch West Wing. It's been out there since and I haven't had any problems with the cable modem. I can only assume that signal to the cable box was overriding the signal to the modem at random times and lengths.

When the Comcast tech comes out here, what exactly should I see them doing to fix the problem?

Thanks for reading!

 

Well after 30 min. of Google I think I found you something.

http://www.hometech.com/learn/coaxterm.html

This is the most important statement in the Tutorial.

If that Dielectric center is not flush so it makes contact with the male F connector when they are mated broad band high frequency signal will leak out causing Modems to drop.

 

Thanks for the info and the link Scott! Hopefully,when my roomate gets ahold of Comcast, it won't be too long for them to come out. Until then, the DVR stays out in the living room!