Broke MoCA II: This time, the wall wart got zapped, too

Back in 2016, I did a teardown of Actiontec’s ECB2200 MoCA adapter, which had fried in response to an EMP generated by a close-proximity lightning bolt cloud-to-cloud spark (Or was it an arc? Or are they the same thing?). As regular readers may recall, this was the second time in as many years that electronics equipment had either required repair or ended up in the landfill for such a reason (although the first time, the lightning bolt had actually hit the ground). And as those same regular readers may already be remembering, last August it happened again.

I’ve already shared images and commentary with you of the hot tub circuitry that subsequently required replacement, as well as the three-drive NAS, the two eight-port GbE switches and the five-port one (but not two, as originally feared) GbE switch. And next month, I plan to show the insides of the three-for-three CableCard receiver that also met its demise this latest lightning-related instance. But this time, I’ll dissect Actiontec’s MoCA adapter successor, the ECB2500C:

I’d already mentioned the ECB2500C a decade back, actually:

The ECB2500C is the successor to the ECB2200; both generations are based on MoCA 1.1-supportive silicon, but the ECB2500C moves all external connections to one side of the device and potentially makes other (undocumented) changes.

And as was the case back in 2016, the adapter in the master guest bedroom was the MoCA network chain link that failed again this time. Part of the reason why MoCA devices keep dying, I think, is due to their inherent nature. Since they convert between Ethernet and coax, there are two different potential “Achilles Heels” for incoming electromagnetic spikes. Plus, the fact that coax routes from room to room via cable runs attached to the exterior of the residence doesn’t help. And then there’s the fact that the guest bedroom’s location is in closest proximity (on that level, at least) to the Continental Divide, from whence many (but not all) storms source.

This time, however, the failure was more systemic than before. The first thing I did was to test the wall wart’s DC output using my multimeter:

Dead! Hey…maybe the adapter itself is still functional? I grabbed the spare ECB2500C’s wall wart, confirmed it was functional, plugged it into this adapter and…nope, nothing lit up on the front panel, so the adapter’s dead, too. Oh well, you’ll get a two-for-one teardown today, then!

Let’s start with the wall wart, then, as usual accompanied by a 0.75″ (19.1 mm) diameter U.S. penny for size comparison purposes:

Specs n’ such:

Time to break out the implements of destruction again (vise not shown this time):

Progress…

Success!

No “potting” in this case; the PCB pulls right out:

The more interesting side of the PCB, both in penny-inclusive and closer-up perspectives:

The same goes for the more boring (unless you’re into thick traces, that is) side:

And now for some side views:

I didn’t see anything obviously scorched, bulged, or otherwise mangled; did you? Let me know in the comments if I missed something! Now on to the adapter, measuring 1.3 x 3.8 x 5.5 in. (33 x 97 x 140 mm). I double-checked those dimensions with my tape measure and initially did a double-take until I realized that the published width included the two coax connectors poking out the back. Subtract 5.8” for the actual case width:

You may have already noticed the four screw heads, one in each corner, in the earlier underside shot. You know what comes next, right?

That was easy!

The PCB then (easily, again) lifts right out of the remaining top half of the case:

Light pipes for the LEDs, which we’ll presumably see once we flip over the PCB:

Let’s stick with this bottom side for now, though:

The lone component of note is a Realtek RTL8201EL Fast Ethernet PHY. The mess of passives below it is presumably for the system processor at that location on the other side of the PCB:

Let’s see if I’m right:

Yep, it’s Entropic’s EN2510 single-chip MoCA controller, at lower left in the following photo. To its left are the aforementioned LEDs. At upper left is an Atmel (now Microchip Technology) ATMEGA188PA 8-bit AVR microcontroller. And at upper right, conveniently located right next to its companion Ethernet connector, is a Magnetic Communications (MAGCOM) HS9001 LAN transformer:

Switching attention to the other half of the PCB upper half, I bet you’re dying to see what’s underneath those “can” and “cage” lids, aren’t you? Me, too:

Your wish is my command!

As with the wall wart, and unlike last time when a scorched soldered PCB pad pointed us to the likely failure point, I didn’t notice anything obviously amiss with the adapter, either. It makes me wonder, in fact, whether either the coax or Ethernet connector was the failure-mechanism entry point this time, and whether the failure happened in conjunction with last August’s lightning “event” or before. The only times I would ever check the MoCA adapter in the master guest bedroom were when…umm…we were prepping for overnight guests to use that bedroom.

Granted, an extinguished “link active” light at the mated MoCA adapter on the other end, in the furnace room, would also be an indirect tipoff, but I can’t say with certainty that I regularly glanced at that, either. Given that the wall wart is also dead, I wonder if its unknown-cause demise also “zapped” the power regulation portion of the adapter’s circuitry, located at the center of its PCB’s upper side, for example. Or maybe the failure sequence started at the adapter and then traveled back to the wall wart over the conjoined power tether? Let me know your theories, as well as your broader thoughts on what I’ve covered today, 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.

Related Content

• Teardown: MoCA adapter succumbs to lightning strike
• Devices fall victim to lightning strike, again
• Lightning strike becomes EMP weapon
• Lightning strikes…thrice???!!!
• A teardown tale of two not-so-different switches
• Dissecting (and sibling-comparing) a scorched five-port Gigabit Ethernet switch
• LAN security for MoCA and powerline

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