 xymox1
Premium Member
join:2008-05-20
Phoenix, AZ
MikroTik CCR1036-8G-2S+
4 edits
20 recommendations |
to Mike Wolf
Re: SB8200 32x8 3.1 cable modem - Feedback and Results threadTo start with... The star of the show... 
Top.. 
Bottom.. If you look kinda closely you can kinda see in this pic the thickness of the copper PCB backplanes is thicker. Cost a little extra, less noise in each layer of board. Its a better PCB then normal. 
Power supply section. 7 rails. All low voltage. Like 1.3 and .9.. Well designed as they dont get that hot. All derived from 12 volts its nocely filtered and has a reasonable cap on the other side. 
The heat sink is BOLTED ON.. Thats a nice touch. Normally I see plastic springy clips that pressure the heatsink against the chip. With the bolt down heatsink a exact distance is maintained between the heatsink and the chip for the thermal pad. This is a way better thermal design. More precision. This puts less stress on the chip and might be better for it over time. This is the arrangement you see on more expensive electronics. Screws in green. 
There is a second heat sink nestled slightly below the first. Good 3D design. Nice space savings. Better thermal coupling so the parts thermal drift together. 
This pic also shows the 4, yes 4, header sockets. i dont know what all these are. Heat sink from the side. Its really thick and beefy. You can see the PCB is thicker then normal. Not from more layers I dont think, I think its thicker copper and better ground planes. You can see the 2nd heat sink and you can see how they even used the Ethernet ports to remove heat by coupling to them too. Good idea. 
Heatsink with its thermal pad. It was not a pad I had seen before. Its was a odd mesh with silicon or something sorta infuzed into the mesh. It did not get on your fingers but if you pushed enough it was like std silicon grease. Sorta. It was a weird pad. Its a serious chunk of aluminum unlike the cheap heat sinks in the other modems ive opened. 
Some ram and eeprom chips ? 
The RF section is just pretty.. This is really the hard part. RF is hard.. They used good precision parts. THICK shielding. Thick top cover. This is just to die for RF.. It makes a difference. Im seeing a lot less errors. My levels are very stable. My TX power does not flap. The ANALOG part of the modem is the real magic, real alchemy. This is a really nice bit of work here. 
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What important is how simple this is. Thats it.. The CM1000 has chips all over it. Its got 6 heat sinks. Its a big PCB with longer traces. This is simple. Its all about performance. Its all well meshed and short distance.
Its cooler then the CM1000.
I gotta take a break. Long work day. Im worn out. It might be tomorrow before I post performance charts. hahahaah... TEASER !!! "Tune in tomorrow for the conclusion of our cliffhanger".... hahahaha...
I might post some later. Let me see how tired I am..
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2 recommendations |
Throw some thermal paste on that chip... Won't hurt it, might make it live a bit longer. Defiantly will help with cooling at least. |
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3 recommendations |
A thick layer of nothing more than thermal paste can act like a blanket and actually keep heat in. Needs to be between a decent heat sink and the chip. |
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2 recommendations |
did u miss the massive heatsink on the chip in the pics? |
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2 recommendations |
No but your post made it sound like your expecting the paste itself to dissipate heat. Misread you I guess.
From what I read above they have a pretty decent contact pad between the chip and sink. |
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to xymox1
Since everyone seems to suggest the unit gets warm, I wonder if you could put it into its own case or a modified case, then add a fan or water cooling (powered not using the unit itself of course); I question if that would improve both the life of the unity and if there would be any other benefits in performance.  |
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2 recommendations |
Honestly replacing the thermal pad with a quality paste would make a huge difference (I've seen components get a 20c drop from just that)
Still not as hot as my Puma 7 XB6 that needs a fan on it. |
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GOD666
Member
2017-Jun-29 8:23 am
said by CamoHiddenDJ:Honestly replacing the thermal pad with a quality paste would make a huge difference (I've seen components get a 20c drop from just that)
Still not as hot as my Puma 7 XB6 that needs a fan on it. I still would be curious as to how a fan with a heatsink and proper quality paste would work on this. It may be something I may try later down the road. |
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3 recommendations |
Unless someone is pulling temps directly off of the chipset, feeling dissipated heat is erroneous. Mine is warm to put my hand over it - maybe the heat sink is doing a stellar job of removing the heat and the chip is operating well under prescribed temps.
I suspect we're chasing a non-problem. |
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Agreed. If there was a serious problem we'd be seeing everyone reporting dead or melted modems by now. Fingers crossed 🤞I didn't just jinx everyone. 😓 |
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 DocDrewHow can I help?
Premium Member
join:2009-01-28
SoCal
Technicolor TC4400
Linksys EA6900
2 recommendations |
DocDrew
Premium Member
2017-Jun-29 6:50 pm
said by Mike Wolf:Agreed. If there was a serious problem we'd be seeing everyone reporting dead or melted modems by now. Fingers crossed 🤞I didn't just jinx everyone. 😓 Being that they were being issued in 2015, it only took 2 years for the Puma6 issue to be really noticed and tracked down... |
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to Mike Wolf
said by Mike Wolf:Agreed. If there was a serious problem we'd be seeing everyone reporting dead or melted modems by now. Fingers crossed 🤞I didn't just jinx everyone. 😓 I don't think anyone's saying there's a serious problem. That the heat is going to melt it down. But given the same chipset, one runs noticeably cooler than the other. What's causing that, hardware design (parts), firmware, combination of both? In the end maybe it has no effect on performance/longevity, but nevertheless I'd rather run the cooler one. |
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chpalmer
1 edit |
I mentioned this mod somewhere.. The pictures linked to are gone now though. » www.dslnuts.com/discussi ··· 2.0.html |
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Maltz
join:2011-01-08
Fayetteville, AR Calix 844G
Netgate SG-2100
Ubiquiti U6-LR
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to rasbjed
said by rasbjed:I don't think anyone's saying there's a serious problem. That the heat is going to melt it down. But given the same chipset, one runs noticeably cooler than the other. I think his point was that you have no idea how much cooler one is running than the other because you're measuring (by feel) the heat leaving the box, not the temperature of the chip. All you're effectively measuring is the wattage. |
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Because the case is smaller on the 8200, it's closer to the heatsink, so you'd be feeling the heat more intensely where as on a larger modem there'd be more space for it to dissipate before it reaches your hand. I bet if someone opened up one of the larger modems and put their hand close to the heatsink it'd feel just as hot. I do agree that it's also entirely possible that firmware can adjust the clock rate of the processor and thus if slowed down less heat would be produced. It's the opposite of overclocking with a computer which generates more heat. |
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 ·Astound
 ·VOIPO
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said by Mike Wolf:I bet if someone opened up one of the larger modems and put their hand close to the heatsink it'd feel just as hot. » Re: [Zoom] Zoom's Motorola MB8600 DOCSIS 3.1 Modem Arrives This MonthI was able to hold my finger on my MB8600 heatsink no problem. Burnt myself on the heatsink of the Linksys CM3025 Puma 6 equipped modem.. Someone needs to try the same (or at least measure) with their SB8200.  Board on the Linksys is 3.5 inches away from the top of the case. Ive got a picture on its thread. Yet the top of that case gets hot enough to smell like its burning up. |
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said by chpalmer:I was able to hold my finger on my MB8600 heatsink no problem. Burnt myself on the heatsink of the Linksys CM3025 Puma 6 equipped modem.. Wow. so maybe Arris is running it harder through the firmware or something. I'm betting the Arris heatsink is going to be hot. |
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·Astound
·VOIPO
1 edit |
said by rasbjed:Wow. so maybe Arris is running it harder through the firmware or something. I'm betting the Arris heatsink is going to be hot. Hard to say.. Id love to know if the CM1000 has similar characteristics to either of these.. BCM3390ZRKF SBG Motorola BCM3390ZKF SBG Arris BCM3390ZKF SBG Netgear edit to add Netgear model # |
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Could the BCM3390ZRKF signify something explaining this? |
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3 recommendations |
said by rasbjed:Could the BCM3390ZRKF signify something explaining this? It's possible. That additional designation may indicate a lower power part than what Arris uses, similar to how Apple used a Motorola 68030 processor in their high end Macs at the time, and a LC68030 on the lower end Macs (the LC versions did not have an FPU and the LC stood for Low Cost). |
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 Almighty1
Premium Member
join:2003-05-14
San Francisco, CA |
Just wished there was a spec sheet that detailed the different part #s. |
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