As the latest entry in my “electronics devices that died in the latest summer-2024 lightning storm” series, I present to you v3.22 (the company’s currently up to v8) of TP-Link’s TL-SG1005D five-port GbE switch, the diminutive alternative to the two eight-port switches I tore down last month. Here’s a box shot to start, taken from a cool hacking project on it that I came across (and will shortly further discuss) during my online research:
WikiDevi says that the TL-GS1005D v3.22 dates from 2009 (here’s the list of all TP-Link TL-SG series variants there), which sounds about right; my email archive indicates that I bought it from Newegg on December 14, 2010, on sale for $16.99 (along with two $19.99 Xbox Live 1600 point cards, then minus a $10 promo code, a discount which you can allocate among the three items as you wish). Nearly 15 years later, I feel comfortable in saying I got my money’s worth out of it!
Here’s what mine looks like, from various perspectives and as-usual accompanied by a 0.75″ (19.1 mm) diameter U.S. penny for size comparison purposes (the switch has approximate dimensions, per my tape measure, of 6.5”x4.25”x1.125”):
I didn’t need to bother taping over which specific port had gone bad this time, because the switch was completely dead!
along with a close-up of the underside label:
Speaking of the “Power Supply” notated on the label, here it is:
In contrast, before continuing, here’s what the latest-gen TP-Link TL-SG1005D v8 looks like:
Usually, from my experience, redesigns like this are prompted by IC-supplier phaseouts that compel PCB redesigns. Clearly, in this case, TP-Link has tinkered with the case cosmetics, too!
Before diving in, I confirmed that a dead wall wart wasn’t the root cause of the device’s demise (it’s happened before). Nope, still seems to be functional:
Granted, while its measured output voltage is as expected, its output current may be degraded (that’s also happened before). But I’m sticking with my theory that the switch itself is expired.
Time to get inside. Unlike other devices like this that I’ve dissected in the past, the screws aren’t under the four rubber “feet” shown in the earlier underside photo. Instead, you’ll find them within the holes that are in proximity to the upper two “feet”:
We have liftoff (snapping a couple of plastic retaining clips in the process, but this device is destined only for the landfill, so no huge loss):
Mission (so far, at least) accomplished:
And at this point, the PCB simply lifts away from the top-half remainder of the plastic shell:
No light guides in this design; the LEDs shine directly on the enclosure’s front panel:
Here’s a PCB backside closeup of the cluster of passives, presumably location-associated with a processor on the other side of the circuit board:
And turning the PCB around:
I’m guessing I’m right, and it’s hiding underneath that honkin’ big passive heatsink.
Let’s start with close-ups of the two labels stuck to this side of the PCB:
And here’s what I assume (due to plug proximity, if nothing else) is the power subsystem:
So, what caused this switch to irrevocably glitch? The brown blobs on the corners of both choke coils were the first thing that caught my eye:
but upon further reflection, I think they’re just adhesive, intended to hold the coils in place.
Next up for demise-source candidacy was the scorch mark atop the 25 MHz crystal oscillator:
Again, though, I bet this happened during initial assembly, not in reaction to the lightning EMP.
Nothing else obvious caught my eye. Last, but not least, then, was to pry off that heatsink:
It was glued stubbornly in place, but the combination of a hair dryer, a slotted screwdriver and some elbow grease (accompanied by colorful commentary) ultimately popped it off:
revealing the IC underneath, with plenty of marking-obscuring glue still stuck to the top of it:
You’re going to have to take my word (not to mention my belated realization that the info was also on WikiDevi, which concurred with my magnifying glass-augmented squinting) that it’s a Realtek RTL8366SB (here’s a datasheet). Note the long scorch mark on the right edge, toward the bottom. While it might have resulted from extended exposure to my hair dryer’s heat, I’m instead betting that it’s smoking-gun (or is that smoking-glue?) evidence of the switch’s point of failure.
I’ll conclude the teardown analysis with a few PCB side views:
leaving me only a few related bits of editorial cleanup to tackle before I wrap up. First off, what’s with the “sibling-comparing” bit in this writeup’s title? While doing preparatory research, I came across a Reddit discussion thread that compared the TL-SG1005D to a notably less expensive TP-Link five-port GbE switch alternative, the TL-LS1005G. More generally, TP-Link’s five-port switch series for “home networking” currently encompasses five products, all supporting Gigabit Ethernet speeds. What’s the difference between them?
Two variations are obvious; four of the five ports in the TL-SG105MPE also support power-over-Ethernet (PoE), and both it and the TL-SG605 have metal cases, versus the plastic enclosures of the other three devices (reminiscent of last month’s metal-vs-plastic product differentiation).
But what about those other three? TP-Link’s website comparison facility fortunately came through…sorta. The low-end “LS” variant is, surprisingly, the only one that publicly documents its performance specs:
- Switching Capacity: 10 Gbps
- Packet Forwarding Rate: 7.4 Mpps
- MAC Address Table: 2K
- Packet Buffer Memory: 1.5 Mb
- Jumbo Frame: 16KB
This data is missing for the others, although I trust that they also support jumbo frame sizes of some sort, for example (the v3.22 TL-SG1005D jumbo frame size is apparently 4KB, by the way). That said, the LS1005G has nearly twice the power consumption of the TL-SF1005D; 3.7 V vs 1.9 W. And what about the latest v8 version of the TL-SG1005D? Its power draw—2.4 W—is in-between the other two. But it’s the only one of the three that supports (in a documented fashion, at least) 802.1p and DSCP QoS.
The ”support” is a bit deceptive, though. Like its siblings, it’s an unmanaged switch, versus a higher-end “smart” switch, so you can’t actually configure any of its port-and-protocol prioritization settings. But it will honor and pass along any QoS packet parameters that are already in place. And now, returning to my other bit of cleanup, per the aforementioned hacking project, it can actually transform into a “smart” switch in its own right:
On a hunch, I decided to crack open the switch and look at the internals. Hmm, seemed there was a RTL8366SB GBit switch IC in there. I managed to download the datasheet of the RTL8366, and whaddayaknow, it actually contains all the logic a managed switch has too! Vlan, port mirroring, you name it, and chances are the little critter can do it. It didn’t have a user-interface though; you have to send the config to it over I2C, as cryptic hexadecimal register settings…but that’s nothing an AVR can’t fix.
How friggin’ cool is that?
There’s one more bit of cleanup left, actually. If you’ve already read either last month’s teardown or my initial post in this particular series, you might have noticed that I mentioned the demise of two five-port GbE switches. Where’s the other one? Well, when I re-plugged it (a TRENDnet TEG-S50g v4.0R, whose $17.99 acquisition dated back to August 2014) in the other day prior to taking it apart, it fired right up. I reconnected it to the LAN and it’s working fine. 
I guess not all glitches are irrevocable, eh? That’s all I’ve got for today. Let me know your thoughts in the comments!
—Brian Dipert is the Editor-in-Chief of the Edge AI and Vision Alliance, and a Senior Analyst at BDTI and Editor-in-Chief of InsideDSP, the company’s online newsletter.
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