SB5120 Motorola modem

by **Rotoman** » Mon Apr 17, 2006 7:36 pm

Guys, need some help. My old modem keeps dying every 15 minutes or so and has to have a hard reboot in order to retain connectivity.

I picked up a Motorola SB5120 modem. The problem I'm having is that it cycles, all the lights are green but the power light just blinks, and blinks and blinks...and guess what? No connectivity. Any help would be appreciated.

by **MAN-AT-ARMS** » Mon Apr 17, 2006 7:45 pm

SB5120's suck. They have buggy firmware.

With the Power light blinking, I would say it can be 3 things..

1. The modem is trying to update it's firmware and is failing..Check the log and see if that's the case.

go to http://192.168.100.1

This is your modem's diagnostics page and see if there's anything suspicious in the log.

2. The modem crapped out in the middle of a firmware update is now screwed.

3. You modem is no longer provisioned (allowed internet access) because of billing or possibly your ISP shut your modem down for abuse (such as DMCA notice for downloading copyrighted material, or you have a virus that is spamming out e-mail)

by **Rotoman** » Mon Apr 17, 2006 7:48 pm

I'm guessing its 1 or 2. Thanks for the advice...I'll try to check the log.

by **Rotoman** » Mon Apr 17, 2006 7:54 pm

ok, no joy on even getting the log page. Any clues to why?

And can you recommend a modem that's TWC compatible? I think this one's going back tomorrow.

by **CreepingCharlie** » Mon Apr 17, 2006 8:09 pm

Thats weird. I have the same model and it works fine.

by **MAN-AT-ARMS** » Mon Apr 17, 2006 8:23 pm

Any DOCSIS modem is 'compatible', it's just the 5120's that are hit-or-miss. For the most part the Surfboards are about the best around.

Connect your computer directly to the modem (no router)

Set the IP on your computer statically to:

IP =192.168.100.20
Subnet mask = 255.255.255.0
Gateway = 192.168.100.1

Then go to http://192.168.100.1

Go to the logs sections and see what's in there..

After your done, set your IP and DNS back to 'Obtain automatically' (DHCP)

By the way, if you picked up this modem to replace an older one, you're gonna have to have TW provision the modem or it won't work.

by **Rotoman** » Mon Apr 17, 2006 8:46 pm

Ok so I have to call TW to get them to provision the modem? What the hell is that?

by **MAN-AT-ARMS** » Mon Apr 17, 2006 8:54 pm

Basically means to activate it. You're gonna have to give them the HFC MAC address on the bottom of the modem.

by **Ldsmith104** » Mon Apr 17, 2006 11:24 pm

Well since we are on the subject maybe you can help me with mine. TWC tech support is useless. I have the same modem and I was having conectivity problems late at night, just random problems. So after like 6 or 8 calls to tech support they can't fiqure it out and tell me to exchange the modem. Now the modem I have stops working at least once a day. I have to unplug it to get it working again. Any ideas?

by **Major SONAR** » Tue Apr 18, 2006 8:35 am

I bought the same modem. I was loosing my connection 10+ per day. I had the cable tech come out every week for 2 months. He even checked the modem and it seemed to be working fine. The cable company did everything from putting new connectors on my old lines to running new lines. Finally they get another tech in to help.

He takes one look at the modem and says, "There's your problem". He installs a Scientific America modem and problem is solved... of course now I have to pay a rental fee on the modem and I wasted $60 on the Motorola SB, but hey, sometimes you win, sometimes you loose.

The tech said the modem works fine in some areas, but not my area. I don't know if he's right about that, but he sure solved my problems.

by **Ldsmith104** » Tue Apr 18, 2006 9:55 am

Could be my problem too, guess I will just have to keep bugging them about it.

by **MAN-AT-ARMS** » Tue Apr 18, 2006 11:52 am

I work for a cable ISP. I know the SB5120's are junk..the firmware in them has all kinds of problems. They may also have hardware design issues. Maybe they are using a new chipset in them. I don't know. Motorola doesn't really offer any details of the changes between models.

When they first came out, we got a shipment of about 100 of them. I would say within a month about 80 of them had to be replaced.

Whenever I'm at a person's house who has one..I take it out.

We currently use the SB5101's, which also had problems at first until they put out a firmware fix, now they work fine.

I've been going back and forth with Motorola's engineering about the 5120's for about a year now. It's always just a runaround. They have the lockup issue you describe where that 'Activity' light will just be pegged on solid with no connectivity), they range higher than the other models and often have poor signal to noise ratios.

But like I said, I've never seen any major issues with Surfboards in the last 6 years. The SB5120 is the first problematic model I've seen.

We don't have many of them here, but the Scientific Atlanta Webstar's seem to be pretty decent. I never saw any problems with those.

by **Ldsmith104** » Tue Apr 18, 2006 5:30 pm

Sorry I have the sb5101. How do I upgrade the firmware?

by **CreepingCharlie** » Tue Apr 18, 2006 5:44 pm

Ok I just looked. I don't have the SB5120 but the SB5100. Is there any difference between them beside the problems in the 5120.

by **Rotoman** » Tue Apr 18, 2006 6:10 pm

Got it provisioned, works great now.

Thanks for the help.

SB5120 Motorola modem

SB5120 Motorola modem

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