Method again in November 2012, I advised you of my travails making an attempt (and in the end prevailing) to get a Linksys DPC3008 cable modem activated on Comcast/Xfinity’s broadband service. The DPC3008 was already used (manufacturing facility refurbished, to be exact) when it got here into my possession, which makes its robustness all of the extra spectacular; it ran hiccup-free (except for Comcast/Xfinity’s varied periodic service points, which weren’t its fault) for almost eight years, together with a residence migration. My sole motivation to maneuver past it was that I required greater upstream bandwidth on account of COVID-19-induced transitions to at-home work for everybody else (I’d been work-from-home for almost a quarter-century at that time) and consequent (and coincident) frequent use of videoconferencing by each myself and my also-work-from-home spouse. Due to this fact, the need for DOCSIS 3.1 service. Due to this fact the NETGEAR CM1100 successor.
The DPC3008, together with its companion energy provide and never-used software program CD, have sat in a plastic grocery bag ever since, awaiting charity-donation relocation (for the reason that cable modem is not partitioned with Comcast/Xfinity, its new proprietor received’t have any downside getting it activated, a minimum of theoretically). Upfront, I assumed I’d take a hopefully nondestructive peek inside and share my reconnaissance outcomes with you. With out additional ado…
The DPC3008 is a now-entry-level DOCSIS 3.0 (backward-compatible with DOCSIS 1.0 and a couple of.0, in fact) cable modem, supporting as much as 8 bonded downstream channels (340 Mbps peak) and 4 bonded upstream channels (120 Mbps peak). Its dimensions are 4.8 x 1.1 x 4.8″ (12.2 x 2.8 x 12.2 cm) and its weight is 0.7 lb. (0.3kg). Right here to start are some overview photographs, as ordinary accompanied by a 0.75″ (19.1 mm) diameter U.S. penny for measurement comparability functions:
As you may already see, the DPC3008 is abundantly outfitted with passive air flow slots, a possible notable contributor to its longevity:
The yellow shade of that Ethernet LAN port appropriately identifies it as supporting GbE speeds:
Much more passive airflow (exhaust, on this case) vents alongside the highest:
and the underside (influx this time…warmth rises, don’ cha know). Be aware, too, the screws in every nook, which I’m already guessing are the gateway to the cable modem’s inside:
Earlier than tackling these screws, let’s snap a closeup of the underside facet label:
together with some photographs of the accompanying energy provide and software program disc:
And now, hopefully, inside we go:
Not a lot notable contained in the enclosure’s prime half, except for a number of gentle pipes that transport the PCB LEDs’ illumination to the surface world:
And talking of LEDs, there they’re, alongside the PCB’s backside edge. Be aware the extra unpopulated LED website towards the proper, alluding to the chance that this similar PCB format could assist a number of cable modem product proliferations:
Additionally be aware the 2 further screws in the proper prime and backside corners of the PCB, holding it in place (the left-side PCB holes are “poke-throughs” for the already empty screw holes beneath, which helped maintain the 2 enclosure halves collectively). Let’s get them out too:
This closeup of one of many two now-empty PCB screw holes additionally offers a zoomed-in view of one of many notable ICs on the board. Google searches for “Unihan T1210” and “TGSA-2501-R” had been unenlightening, however given its bodily traits (bundle, lead depend, shade, measurement and form) and its proximity to the Ethernet connector, I’m guessing it’s the LAN transformer:
Additionally be aware the tape spanning the Ethernet connector and the Faraday cage to its left. It’s seemingly metallic in fibrous development, main me to suspect it acts as a grounding strap.
Equally, a closeup of the opposite now-empty screw gap additionally revealed intimately the system DRAM IC, a Hynix H5PS5162GFR 512 Mbit DDR2 x16 SDRAM:
Whereas we’re at it, right here’s a closeup of the opposite reminiscence (I’m fairly positive) IC on the board, to the proper of the warmth sink:
Parts of the bundle topside marking are obscured by the quantity sequence “44” (I think referencing the firmware model programmed within the system) hand-scribbled on prime with what seems to be like a black magic marker. Whereas I can’t verify the density, it’s from Winbond. My guess is that it’s one of many firm’s SPI NOR flash recollections, meant for code storage.
And right here’s one other PCB closeup, of what appears to be the cable modem’s energy subsystem, containing (amongst different issues) three IT7612DC/DC converters (i.e., voltage regulators) from ITE Tech and three giant, conveniently value-labeled inductors:
With the ultimate screws eliminated, the PCB lifts proper out of the enclosure’s remaining backside half:
As beforehand talked about, my as-always aspiration is to go away the torn-down affected person in a sufficiently intact state that it may be reassembled in totally purposeful type afterwards for subsequent donation. That mentioned, in trying on the Faraday cage within the higher left nook, I suspected I’d be capable of pop the lid off with a flat head screwdriver (appearing as a lever arm in partnership with the warmth sink) after which securely push it again on prime afterwards. Let’s see:
Numerous passives inside, as anticipated:
The one notable IC alongside the underside edge has the next four-line marking (to one of the best of my previous, drained eyes’ skills):
Google means that the “KMLG10” could also be a low-noise RF amplifier from KEC Holdings, which might make sense given its location; right here’s a DeviWiki entry for an additional cable modem with the identical IC listed within the “further chips” part.
Talking of “leaving units sufficiently intact that they are often reassembled and reused”, I’d hoped to additionally be capable of get that warmth sink off. However a peek on the PCB bottom left me skeptical:
Be aware the manually twisted mounting “prongs” the place they exit the PCB. I think that even when I acquired them untwisted, they’d subsequently snap upon tried reassembly…even assuming I might get the warmth sink off after which meaningfully again atop the IC together with some thermal tape or paste. However talking of DeviWiki, it seems we don’t have to trouble with the heatsink, as a result of we already know what’s beneath: Broadcom’s BCM3382 system SoC.
And with that, I’ll wrap up this teardown evaluation, which I’ve already supplemented with a profitable reassembly previous to writing these phrases. Reader feedback are as-always welcome!
—Brian Dipert is the Editor-in-Chief of the Edge AI and Imaginative and prescient Alliance, and a Senior Analyst at BDTI and Editor-in-Chief of InsideDSP, the corporate’s on-line publication.