Any ideas on how to fix my modem's T3 & T4 time-out problem?
January 18, 2015 4:22 PM Subscribe
In the last six months my Charter cable modem has started randomly rebooting itself, sometimes up to 15-20 times a day, due to T3 & T4 time-outs. Could you please look at my modem logs and tell me if you have any other ideas about how to fix this problem?
My problem: In the last six months my Charter cable modem has started randomly rebooting itself, sometimes up to 15-20 times a day. As you can imagine, this is pretty frustrating since any streaming or downloading gets interrupted, or work grinds to a halt for 3 or 4 minutes until it's back up.
Logging into the modem, I can see in the system logs that it's caused by T3 and T4 time-outs that make the modem reboot. Charter Tech Support has been completely unhelpful. I've gotten "Reboot the modem!", "It's your router's fault!", "Your speed test looks fine!", and "You need a new modem!". For the record, I'm on my third modem and, even though it seems like routers don't cause T3/T4 time-outs, I'm on my second router. Every time I call Tech Support I have to go through the "reboot the modem" nonsense while I try to get to someone who's actually heard of a T3 time-out before.
They sent out a technician who had me run a speed test, said the connection looked great, and left. He was there for about six minutes and I was charged $45 for this. I've been informed future tech visits will also cost $45, unless the technicians personally decide to waive the fee. Charter seems to hire a lot of contractors and I can't request a higher tiered in house guy who might be more knowledgeable about the problem (I asked.) My area doesn't offer Google Fiber or AT&T U-Verse, so I have no other options besides slower DSL.
Things I've tried:
Changed the modem three times (first: Motorola SURFboard SB6121, 2nd: Cisco DPC3208, now: Motorola SURFboard SB6141)
Putting the modem in different rooms, connected to different coax outlets
Putting the modem and router on a different power strip
Removing all coax splitters from the line, which I've heard can cause line noise
I live in an apartment building. The coax line runs out the wall to a central utility box on the wall. Within the utility box, the cable connections are housed in a separate metal box with a padlock on it and a sticker that says "Stealing cable is a crime!" or something along those lines. My current suspicion is that water or the elements have gotten to whatever splitter or connections are in that metal box, but I can't investigate or redo the connection because of the padlock.
I'm trying to eliminate every other thing I can think of before I pay for another technician to come out and beg him to look into that locked cable box.
Here are screenshots of my modem log and signals page:
Log
Signals
Would an Uninterruptible Power Supply be of any benefit to T3/T4 time-outs? I doubt it, but I thought I'd ask.
Is there anything else I should try?
My problem: In the last six months my Charter cable modem has started randomly rebooting itself, sometimes up to 15-20 times a day. As you can imagine, this is pretty frustrating since any streaming or downloading gets interrupted, or work grinds to a halt for 3 or 4 minutes until it's back up.
Logging into the modem, I can see in the system logs that it's caused by T3 and T4 time-outs that make the modem reboot. Charter Tech Support has been completely unhelpful. I've gotten "Reboot the modem!", "It's your router's fault!", "Your speed test looks fine!", and "You need a new modem!". For the record, I'm on my third modem and, even though it seems like routers don't cause T3/T4 time-outs, I'm on my second router. Every time I call Tech Support I have to go through the "reboot the modem" nonsense while I try to get to someone who's actually heard of a T3 time-out before.
They sent out a technician who had me run a speed test, said the connection looked great, and left. He was there for about six minutes and I was charged $45 for this. I've been informed future tech visits will also cost $45, unless the technicians personally decide to waive the fee. Charter seems to hire a lot of contractors and I can't request a higher tiered in house guy who might be more knowledgeable about the problem (I asked.) My area doesn't offer Google Fiber or AT&T U-Verse, so I have no other options besides slower DSL.
Things I've tried:
Changed the modem three times (first: Motorola SURFboard SB6121, 2nd: Cisco DPC3208, now: Motorola SURFboard SB6141)
Putting the modem in different rooms, connected to different coax outlets
Putting the modem and router on a different power strip
Removing all coax splitters from the line, which I've heard can cause line noise
I live in an apartment building. The coax line runs out the wall to a central utility box on the wall. Within the utility box, the cable connections are housed in a separate metal box with a padlock on it and a sticker that says "Stealing cable is a crime!" or something along those lines. My current suspicion is that water or the elements have gotten to whatever splitter or connections are in that metal box, but I can't investigate or redo the connection because of the padlock.
I'm trying to eliminate every other thing I can think of before I pay for another technician to come out and beg him to look into that locked cable box.
Here are screenshots of my modem log and signals page:
Log
Signals
Would an Uninterruptible Power Supply be of any benefit to T3/T4 time-outs? I doubt it, but I thought I'd ask.
Is there anything else I should try?
Also, do you have TV service? Comcast cared more about the fact our receiver couldn't keep a lock and kept rebooting than they did about our cable modem.
And I'm guessing you own your modem(s), but as a last ditch effort you could temporarily lease a new modem from them. If their leased hardware doesn't work, they're responsible for repairing it or replacing it.
posted by fedward at 5:27 PM on January 18, 2015
And I'm guessing you own your modem(s), but as a last ditch effort you could temporarily lease a new modem from them. If their leased hardware doesn't work, they're responsible for repairing it or replacing it.
posted by fedward at 5:27 PM on January 18, 2015
Best answer: Your downstream signal looks pretty good. Upstream seems to be requiring a bit more power than is optimal. Is there any way you can reduce the number of splitters between the point of entry and your modem? Or perhaps switch to one big splitter rather than multiple smaller ones?
They make unbalanced splitters that will have two ports that are at -7 or so dB relative to input and one that is only -3dB down. If you're going through multiple splitters on the way to the modem, connecting directly to the hotter port on one of those might help.
Also, if you have access to the point of entry, you might check that all your connectors are still bright and shiny and show no evidence of water intrusion. On more than one occasion I've had water get into the cables or corroded connectors that cause problems presenting much as yours do. The last time it was pretty easy to diagnose since water literally started leaking out when I disconnected it. If this is your problem you'll need to replace the splitter your entry cable is connected to, as the water will get inside and mess it up permanently.
In short, check or replace all splitters and cable ends and reduce the number of splitters between the street and your house to whatever extent possible.
posted by wierdo at 8:40 PM on January 18, 2015
They make unbalanced splitters that will have two ports that are at -7 or so dB relative to input and one that is only -3dB down. If you're going through multiple splitters on the way to the modem, connecting directly to the hotter port on one of those might help.
Also, if you have access to the point of entry, you might check that all your connectors are still bright and shiny and show no evidence of water intrusion. On more than one occasion I've had water get into the cables or corroded connectors that cause problems presenting much as yours do. The last time it was pretty easy to diagnose since water literally started leaking out when I disconnected it. If this is your problem you'll need to replace the splitter your entry cable is connected to, as the water will get inside and mess it up permanently.
In short, check or replace all splitters and cable ends and reduce the number of splitters between the street and your house to whatever extent possible.
posted by wierdo at 8:40 PM on January 18, 2015
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When this happened to us (with Comcast) it turned out to be a bad piece of distribution equipment that served our neighborhood, not just our building. We lived with it for a couple weeks until they finally repaired it, because when we called it in they at least admitted that they knew of bad equipment in our area and they were working on replacing it (not sure why it took as long as it did, but they owned up to it and they fixed it). If you have the same problem with multiple modems, the problem most likely isn't your modem.
What you want them to do is a line test, not just a speed test. It will help if you call in the middle of one of these episodes (looking at that log file, the timestamps are all minutes apart, which means it fails, reboots, gets a signal, and then fails again, lather, rinse, repeat). They can reprovision your modem too (send it a hard reset and a new software payload) but IME that's unlikely to help, while a test in the middle of one of those episodes should. If they do a line test during one of these episodes they should have some idea where the problem is happening. If they can't find anything they should be able to move you to another terminal. The tech who came out should have done a line test, and if he didn't, and it were my bill, I'd be yelling at them about how they need to send another tech to do a line test and refund me for the first service call because the guy didn't do his job.
As a side note, your signal strength is perhaps a little bit lower than it could be. I think you're actually within spec (based on a memory of something I read while dealing with our similar problem – don't take that as authoritative). After our line flapping was fixed we had a tech visit for a different problem with our TV service. He swapped our TV receiver for that, but while troubleshooting he noticed that our modem had similar 0s and -1s. Before he left he reterminated wire, replaced a splitter, and then called in and they boosted our signal until we had +3 or so.
posted by fedward at 5:24 PM on January 18, 2015