Failed: Counterfeit Linksys/Cisco PAP2T Power Adapter (MS-050200)

If I had three words to say, it would probably be just my luck. On 20th February this year, the Linksys PAP2T ATA that provides VoIP phone service to the house went down because of a power supply failure. Knowing that bad things can happen, I always had a spare device, but I didn’t know until I examined it closely, that my spare device was a counterfeit. Oh well, I thought. At least I can still use the power supply – so I plugged it in and the line came back up.

I always thought that this would be trouble, as people complained their counterfeit PAP2T’s error out on a red power indication, so I prudently ordered a spare power supply only for it to be lost in the mail after a few months of waiting.

Then, yesterday, the inevitable happened. The counterfeit supply decided to give in, and the PAP2T gave out the dreaded red power LED indication after a few boot loops. Another bad power supply!

Taking it Apart

This unit came with a counterfeit PAP2T, so I’m going to presume it’s a counterfeit power supply. It had a US two-blade power input which I forcibly bent to accommodate Australian sockets.

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This photo was taken after the case was forcibly cracked open, showing the exterior and model number.

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Well, if the cause isn’t already clear, it failed because of the same reason as the other supply – a failed capacitor on the output side. While it is potentially repairable, the case suffered quite a bit of damage in opening, and I don’t have much faith in the quality of the other components in the design. A KSD branded primary side cap? Never heard of them.

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A side profile shot shows you just how shoddy the parts can be – the input filter inductor (at least they had one) has a band at the top which is badly glued out of place. Other than that, some of the rest looks okay, as it’s fused on the primary side.

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A look at the underside shows the primary to secondary isolation is good as well. However, the unit was quite hot as I removed it from service, so I can’t help but think that the capacitor failure may have caused stress to the other components, so lets just bin this and buy another. Power adapters are easily exchanged …

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The failed cap was a Teapo (rhymes with cheapo). While Teapo doesn’t have a stellar reputation, I’ve personally not had that many issues with Teapo caps, which leads me to believe that some of the bad caps we see venting are actually not solely a result of poor capacitors. For example, using a capacitor which was under-specced for the expected ripple current or with a lower than necessary temperature rating will overstress the capacitor, causing it to heat up, and slowly boil away.

Of course, there definitely are off-brand capacitors which are questionable on a lifetime basis, and counterfeit components as well which emulate the markings and design of quality components but without the same level of performance.

Conclusion

This year hasn’t been a good year for my VoIP gear – now the home PAP2T is running from the supply pinched from the SPA112 while I try to source two decent replacements without breaking the bank. I do have another PAP2T with an identical power supply to the first that failed … bought at the same time … so maybe make that three

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3 Responses to Failed: Counterfeit Linksys/Cisco PAP2T Power Adapter (MS-050200)

  1. philectro says:

    I had the same trouble with the original PS

    the actual power is the pa100, i have also find the replacement ref from phihong at the time

    On my side when the ps failed, i have buy a usb power 3A and cut the cable from the ps, soldering it to a usb connector as it use 5V 2A max.

    But i had problem, crackle in the sound, and the web server on the pap2t answer a bit when it wants to(random response time). I worry if the old now 9 years old cap in the pap2t should not be changed or if the pap2t is not damaged.

    I have buy a spa112 today with 20% off for replace my pap2t and i’m going to test the pap2t with the pa100 ps.

    • lui_gough says:

      It could be possible the capacitors inside the PAP2T are bad, but more likely is that the USB power supply you’re using isn’t quite holding its output voltage steady. I’ve tried splicing the cable of my PAP2T to various 5v supplies, and many of them do cause the symptoms you’ve suggested. Ultimately, I found one old tablet power supply which was made by Delta Electronics that was steady enough – shortening the length of the cable to reduce voltage drop losses also helped. Needless to say, the three PAP2Ts I have, one is still on its original supply, one on the hacked Delta Electronics supply, and the last is using the Phihong that came with the SPA112 which I’m not currently using.

      – Gough

      • philectro says:

        Ha yep my usb PS i have buy is made by delta electronics too because i wanted something “good” and that i know, It’s their “innergie” brand. I have needed to change the usb connector recently because i find it was a bad one, the contact was not good. Now it seems okay but the other leaved some plastic particles on the other usb connector which may have lead to crackle.

        it’s the innergie 15W PS model, but i think it’s really 2x 1.5A PS even if they indicate 2.1A on one port. So maybe i stress too much the PS.

        You answered so quick !

        I will post later after some test with the pa100 on the pap2t.

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