[SOLVED] "Upgraded" to an Arris Surfboard SB6183 and am now experiencing 30 mbps when I am paying for up to 200 mbps

[RDLopez]

I recently switched out my Motorola Surfboard SB6120 for an Arris Surfboard SB6183. I have been paying Comcast for an internet plan that should provide me with speeds up to 200 mbps. With my old Motorola modem, I was getting around 110-120 mbps on speed tests, so I thought I'd try a new modem. I picked up an Arris SB6183 and activated it earlier this evening and found I was getting speeds averaging 30 mbps!

I contacted the Arris customer support line and they had me check my Downstream and Upstream Bonded Channel values to look for discrepancies in Power and SNR levels. There were 4 Downstream channels that had discrepancies and 2 upstream channels that had discrepancies. They said it was something my ISP had to fix. The Arris folks said perhaps it's a coaxial cable issue, but I highly doubt that because my Motorola provided speeds over 100 mbps with the same coaxial cable. They also said perhaps the Comcast folks were sending the wrong boot file to my modem.

I contacted Comcast and explained the situation. They ran me through the standard troubleshooting steps like resetting my modem, switching my ethernet cord, trying my connection on both my laptop and my desktop. Nothing helped. I asked the Comcast folks about perhaps sending the wrong boot file to my modem like the Arris agent had suggested and they were adamant that was not the case.
They said they could not do anything else on their end besides having a technician come out to see what's going on, which understandably will be delayed for quite a bit because of COVID.

Is there anything else I can do to troubleshoot besides wait for the technician to come check things out? I am trying to switch back to my old Motorola modem, but the Comcast folks said that it would take another 24 hours to switch back because removing my old modem from my account put it in a back system limbo that won't let me reactivate it for 24 hours. I can also post the Downstream and Upstream Bonded Channel values for my new SB 6183 if that would help diagnose the situation.

Please help!

 

[bill001g]

That is strange that you where using that 6120 modem on 200mbps plan. It really can only get 150mbps since it only runs 4 channels.

Your new modem should be 4 times as fast because it can run 16 channels...I am too lazy to find the actual number.

The number of channels the modem can do is only 1 part. The ISP may choose to only use say 8 for your plan.

These new additional channels run on different frequencies and may not work as well on the same cables that pass other frequencies.

So it could be the cable that is having issues with certain frequencies. Some old coax cable splitters would block certain blocks of frequencies.

I would take the cable modem and hook it up where the cable form the ISP comes into your house. Compare the channel numbers strength etc when it hooked here compared to its normal location. This is to see if it is something with the wires in your house. You will always see a little bit of difference because any extra cable decreases the levels, you are looking for large changes. I suppose you could hook your PC up and see what you get for speed also.

Although the ISP have long times because of all the people working from home the ISP can fix things that do not require them to come into the house much easier.

Call the ISP with the modem hooked at the entry point they can see the numbers since the modem send them to them.

 

[beers]

Can you post the stats from the modem?

I had to recently fight Comcast since they jacked up my account on my existing modem, continued to blame the modem and refused to do anything to help. I swapped it, activated, and then swapped back to my previous one, works fine again. They have some crappy misprovisioning problems they refuse to address, it's always easier for them to blame the customer.

You could call the tech although they refuse to touch anything if you're not using their modem, although the dude should have a meter to check/resolve physical signal issues.

 

[SamirD]

It's the boot file--100% sure on this as I've seen it before with Comcast.

Put your old modem back and it should work fine again. If it doesn't, call them and act like it was working fine and just stopped. They'll get it working again on their end. Then you can try the swap and self-activation again.

Now the reason you may have not gotten the proper boot file is that they're not sending it to you because the modem is no longer supported. If it's not supported, you get a generic 30Mbps boot file as you're getting right now. I went through this whole process myself at one point...