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Forum Discussion
CM1150v Intermittent Slowness and Channels not locking
Hello, Having an issue where the CM1150v modem I have went from perfectly fine to all of a sudden flashing the downstream light repeatedly. My speeds went from 300+ to about 20-30mbps. It's been ...
You have a lot of errors in your line. And you're directly connected to where the cable enters the house with no splitters? I'd have them check it again and have them hook up one of their modem only devices if they're blaming the modem. It potentially could be the modem but with that many errors, I'd be inclined to think its something from their box to your house.
You also didn't capture you ofdm channels. Thats the key for gigabit.
They hooked up their tester device, the XM2(?) to the line and tested it. They got over 1gbps on their device and when plugging the modem back in, the modem was working correctly at that time as well. An hour after they left, it was back to the 20-30mbps. A day later, it was back up to normal speeds, then a day after that continuing to now, it is back at 20-30 mbps. It's only when the downstream light is flashing and that channel isn't locked that this happens.
The cable goes into the house, then splits to the TVs and the modems using a MOCA splitter (they just put this in replacing a powered amplifier). This line goes directly from that house splitter to the modem.
Comcast keeps wanting to blame the modem and the tech said please replace that modem before calling us back out.
I don't have gigabit yet, was going to upgrade in the future. Only have about 350mbps. I'll try to capture that section when I get home.
Here is when it is working: https://i.imgur.com/ynacZ9j.jpg
So when they're there and its directly connected it works on your modem and on theirs. Then they unlook it and add the splitters/moca adapters (why moca?) and now it has issues.
If you absolutely need the splitters it should go like so:
incoming line--- a 2x port splitter with one connection going to the modem and then other to the rest of your tv's/splitters/moca adapters. The modem is more sensitive to problems than what your tv's/moca adapters are. So it should be first in the line and only on a 2x port splitter. You can add splitters after that to run the rest of your device but the modem should have its own dedicated line.
If you are directly connected to the line coming in without the splitters/adapters/etc, do you get gigabit?
Even when its running well, you still have a lot of erros.
- Not exactly, let me try and give a timeline:
Bought modem in May, worked until a week ago. Don’t know what the errors looked like prior to this.
Modem starts flashing downstream light a week ago and notice download are going excessively slow. Speed test reads 20-30mbps depending on the run.
Tech comes Saturday. Modem still flashing downstream. Show tech it’s flashing and that one of the channels isn’t locked including the page with the errors on it. He states that all the information showed us normal, proceeds to check lines from their box, into the house, and to the modem. All lines check out according to the tech. We wait about 30 minutes for an additional tech with the testing tool. During that time, he swaps our powered amplifier for a MOCA splitter (his words) to feed the whole house more efficiently and without an additional point of failure in the form of the powered amplifier.
Additional tech arrives, connects cable, has trouble running speed test. Disconnects coax from modem. Line reads 1gbps on their test device. Plug the cable back in the modem and downstream stops flashing, modem is at correct speeds again. They leave.
Hour later: flashing downstream and low speeds.
Next day: full speeds
Day after: flashing and low speeds
This setup has worked great until a week ago with our correct speeds and has been like this for years, just had a Comcast modem until this past May.
My direct line is in the attic and I don’t have an Ethernet cable long enough to reach my desktop if I put the modem in there to test it unfortunately. I don’t have any portables with one either. I suppose I can buy an adapter for my laptop and try it out connected directly to the main line.The reason I think its the cable or how you've split the signal on the cable is, for the most part, modems either work or they don't. There's not a whole lot of in-between when they go bad.
You must have coax where the modem is. But you have a bunch of devices connecting in between where the cable comes in and where the modem is. Remove them and just run a direct connector (https://www.amazon.com/Connector-VCE-Extension-Adapter-Connects/dp/B01F54KYO2?ref_=fsclp_pl_dp_1) without the splitters/amplifiers/etc. See if it works then. The cable company is only required to get a good signal to your house. After that, if you add a bunch of splitters/moca adapters/poor/cheap cables then its on you and they aren't required to do more.
So your goal is to see if it works when it enters your house. If it does, it isn't the modem or the signal coming in, its everything you introduced after it enters your house.