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SpeedStream 4100B - No internet

It is possible that the wall wart died. They tend to die faster than the modem. This happens for all modems, especially 2Wires.

If you have a multimeter, check the power output on the wall wart.
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TCE Weather

Can I try the 5100B power supply on the 4100B? Both modems are 12v with the 5100B rated 700ma and the 4100B rated 500ma. The plugs appear to be interchangeable.

Thanks.

You should be able to use the 700ma 12v power supply for the 4100B. The 700ma is the maximum rated output, so it will provide sufficient current to a device that probably draws much less than 500ma. I wouldn't be so sure about the reverse however.

It should be fine. Hopefully it is just the power supply.

Thanks. I gave the bigger power supply a try with no luck. The DSL light turned red and the Internet light stayed dark after which the 4100b went into an endless reboot loop.

When initially booted all lights turned bright green briefly.

reply to jmorlan
It maybe dead or more likely a capacitor in it might have died or leaked. If it is just a capacitor problem, that could be repaired, but it probably isn't worth it.

Buying a replacement is probably cheaper than a capacitor replacement.
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TCE Weather

Thanks.

Decided to replace it. Used on eBay with no power supply - $9.99.

reply to jmorlan
I hope your replacement works well and isn't a dud.

For grins, you might open up your failed 4100b and look at the capacitors to see if they have leaked. If they have, then you would be certain of its death.
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TCE Weather

Fortunately I have a good working 5100b to use in the meantime.

I popped open the 4100b and I see no obvious signs of capacitor leakage, nor did I detect any signs of swelling in the capacitors.

But if it's not obvious I could easily miss it.

reply to jmorlan
I've always thought the caps in the modem would be the most likely failure point. Specs from Siemens stated that the MTBF for these 4100 modems is 50,000 hrs. That is almost 6 years of continuous use.

Do you think that you have used it that long?
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TCE Weather

My records indicate I bought the 4100B used in January 2008 and it has been in continuous use ever since. So only three years.

The 5100B I bought used in August 2004 and it was in service until I replaced it with the 4100B. So it's been in use for 5 1/2 years.

But in both cases, I bought them used so don't know for sure how long they were in service before me.

Heat is also a factor in how long they last. Was your 4000 nearer a heart source?

Not really. It sat on a shelf under my desk next to a router.

reply to d_l
Just got the replacement. Bad news.

It appeared to be brand new with all the stickers and I was able to get as far as entering in logon credentials. After that it just wouldn't work. I couldn't connect to the internet, nor could I connect to 192.168.0.1. On hard reset the modem only displayed the power and ethernet lights green. The other three lights were unlit.

Tried several resets with the modem and computer. Had the modem connected directly to the computer during these trials. Nothing.

I am starting to wonder if it wasn't the power supply after all. Perhaps a surge of some kind that killed the modem.

reply to jmorlan
So you are thinking your original power supply has somehow killed both your original and the new modem?

If you don't have a multimeter, perhaps you could take that power supply to the Shack to check its output.
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TCE Weather

reply to jmorlan
Can you describe the condition of the modems lights when first turned on

Yes, they all come on green.

reply to d_l
Finally got a chance to take the power supply to Radio Shack. Their meter said it's putting out 17 volts instead the the 12 it's supposed to.

I bought a replacement 12v supply to test, but both 4100B modems still fail with the replacement power.

So I still think the bad power supply probably killed both modems.

FWIW I've owned a hand full of 4100's, 4100b's, 4200s and each and every one of the power supplies that came with them all outputted 17volts. Honestly sounds like something went kaput within the modem itself.

reply to jmorlan