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kornfan4evr

join:2006-01-31
Manteca, CA

Motorola SB6120 Bricked?

I purchased a SB6120 to use with my comcast subscription in order to save a bit of extra money. Needless to say it's pretty close to paid itself off after the 6 months I've owned it. However, 2 days ago I noticed my PC was not connected to the internet.

The link light is actually Purple (was originally blue...) and the send and receive lights are solid blue. This happens even after removing it from a power source for ~10 seconds and plugging it back in. It takes no time in order for the lights to become solid. Just as soon as its plugged in the lights all become solid. Also the weird thing is that the Power LED does not come on.

I am unable to ping the unit (192.168.100.1), as well as attempt to view the config page from within a web browser. It doesn't seem to communicate with the PC what so ever (no action from the NIC Card/On Board NIC).

I am lead to believe that the unit is just bricked. It was plugged into a surge protector and was not in contact with any static material.

Do these units fail this much with out a 3rd party at fault? (newegg reviews did not carry much of the bricks other than ISP @ fault).


telcodad
Premium
join:2011-09-16
Lincroft, NJ
kudos:15
According to this document on the SB6120 modem: »www.motorola.com/staticfiles/Vid···uide.pdf
it looks like your modem is failing the Power On Self Test.

kornfan4evr

join:2006-01-31
Manteca, CA
Thanks for taking the time to reply! As I have not been able to find any DIY fixes for this issue I'll go through the proper RMA Channels. Thanks again!

rody_44
Premium
join:2004-02-20
Quakertown, PA
Reviews:
·Comcast
reply to kornfan4evr
Comcast is them to modem. Modem to your computer is generally a computer or modem issue. A way to tell for sure is disconnect the coax from comcast and power cycle everything. If you cant connect to your modem without the coax connected it 100 percent has nothing to do with comcast. In real life a modem might last years but it might only last until its off warranty also. YMMV when dealing with a purchased modem. I have went thru 4 and all have lasted different amounts of times. If you cant reach your modem with a web browser its a modem problem and nothing to do with comcast.

andyross
Premium,MVM
join:2003-05-04
Schaumburg, IL
reply to kornfan4evr
As a last check, see if you have a matching power supply. Many modems and it seems computer electronics seem to use the same 12V supplies. If so, you can see if swapping supplies will help, just in case.


telcodad
Premium
join:2011-09-16
Lincroft, NJ
kudos:15
reply to rody_44
Geez, after reading a number of stories on this forum lately of modems suddenly going bad, I'm wondering if I should purchase a good quality coaxial surge protector, like this one from TII on Amazon's site: »www.amazon.com/TII-Broadband-Cab···016AIYU6

My modem is already plugged into an APC UPS that provides surge protection on the power side.

The only other connection is the Ethernet one, but hopefully the closely connected router/switch would take the brunt of any surges coming down on those lines!

mrschultz02

join:2007-09-10
Media, PA
reply to kornfan4evr
said by kornfan4evr:

I am unable to ping the unit (192.168.100.1), as well as attempt to view the config page from within a web browser. It doesn't seem to communicate with the PC what so ever (no action from the NIC Card/On Board NIC).

Is your PC getting an IP address from the modem? In other words is DHCP working on the modem? If not then you'll have to do a manual TCPIP setup on the computer before you can be sure you can't get to the web page on the modem. If your NIC(s) on the computer have connection LEDs and they are not lit that would also be an indicator of a dead modem, but also try a different cable just to rule out a broken wire.

Don't know why they don't put a factory reset switch on the SB612X modems, but try removing power for a day to see if it resets. Then power it up with no coax or ethernet attached and see what the lights do.

kornfan4evr

join:2006-01-31
Manteca, CA
reply to kornfan4evr
Heres a bit of an update. After paying motorola 15 dollars in order to ship me a replacement SB6120 (havent arrived, arranged it on friday) I decided, after having it unplugged nearly all weekend, to try it out again. Sure enough it works! Pretty odd really...now lets see if I can cancel this order...


defiant
MVM
join:2000-09-04
Monroe, MI
kudos:2
What was the $15 for exactly?


ArrayList
netbus developer
Premium
join:2005-03-19
Brighton, MA
reply to telcodad
Never plug coax into a surge protector. If comcast grounded it correctly you will be fine. Running the coax through the protector will just put noise into your line.


gar187er
I do this for a living

join:2006-06-24
Dover, DE
kudos:4
hes not using a traditional surge protector, hes a using a gas tube surge protector inline...it doubles as a ground block.....good product...
--
I'm better than you!


gar187er
I do this for a living

join:2006-06-24
Dover, DE
kudos:4
reply to telcodad
thats for lightning....not regular surges from the power company.....

you wont find surges coming down coax unless its hit by lightning....the taps are power blocking, so no ac/dc on the line to your house....
--
I'm better than you!


telcodad
Premium
join:2011-09-16
Lincroft, NJ
kudos:15

1 edit
While that unit was labeled as a "Lightning Surge Protector" by Amazon, the description says it "provides superior protection against high and low voltage transient surges."

I figured to replace the existing standard grounding block with it.

I found a spec sheet for the series at: »www.digicomm.com/tii210.pdf

It says the units have a 150–300 VDC Breakdown and an Impulse breakdown rating of 450 Volts.


telcodad
Premium
join:2011-09-16
Lincroft, NJ
kudos:15

1 edit
I was looking through some electronics parts I had and found an old Radio Shack model 61-2145 Cable Modem Network Surge Protector that I had picked up on a clearance sale a few years ago. Here is the info and specs: »support.radioshack.com/support_a···5677.pdf

Down-Stream:
Frequency Range 42 - 850 MHz
Insertion Loss -1 dB
Up-Stream:
Frequency Range 5 - 42 MHz
Insertion Loss -0.5 dB
Max. Surge Current: 10 kA (8 x 20 uS)
Surge Life: 500 A (10 x 100 uS, 500 Shut)
Breakdown Voltage: 60 - 90 Volts
Response Time 100 nS

You can see a picture of it here: »www.ebay.com/itm/RadioShack-61-2···43227793

I like the lower breakdown voltage, but it may have more insertion loss than the TII units.

I also found that APC once made a surge protector for coax cable lines (model PV): »www.apc.com/resource/include/tec···e_sku=pv

Let Through Voltage: 85 V
Minimum Breakover Voltage: 27 Vdc
Typical Peak Surge Current Handling: 400 Amps with 8/20ìs test waveshape
Frequency Range: 1 MHz through 1.45 GHz, compatible with Low Noise Blocks (LNBs) for C and Ku bands
Insertion Loss: 0 dB to 3.0 dB over rated frequency range

Again, the breakdown voltage was lower, but it looks like it had a greater insertion loss than the TII units.


gar187er
I do this for a living

join:2006-06-24
Dover, DE
kudos:4
stay away from radio shack.....remember; theyre the ones who think gold plated f connectors increase bandwidth......they like to lie.
--
I'm better than you!


EG
The wings of love
Premium
join:2006-11-18
Union, NJ
kudos:10
IMO, don't use an inline coax surge protector at all !!