Hi all,

          Just picking up on an old thread. https://community.tp-link.com/en/business/forum/topic/254126.

I've an EAP225 that looks to have exactly the same issue, in that the TVS diode (T9) has burnt out due to me stupidly powering it from a 48V passive brick I had for a EAP245. 

I've done some comparing against a working unit and found so far that the T9 TVS diode appears to be there to protect against voltages exceeding the usual 24vdc when supplied from the correct passive source!  The T8 TVS diode to the right appears to be the same arrangement but for the 48V supply when powered by an active POE source. As I had nothing to lose I was wondering if it's possible to resurrect the unit just on this supply, and so I've had mine apart and done some investigating.

So T9 diode has failed and gone short, this appears to then take out the 12V generated internally by both of the passive and active supply inputs as it's effectively shorted by T9 (can be measured with a meter).  By removing T9 (and ferrite link FB24 which in my was required as T9 blowing apparently created a fault in the PCB below), this short can be removed and then when powered by the active POE circuit, the internal 12v supply is ok (measured between the furthest connections on FB24 and FB25 - or across the T9 pads), but unfortunately for me there's something else that's happened which I'm not sure about and I'm not sure if it's mine only where the original fault was major enough to affect the PCB.

Anyway, if anyone else has had the same issue and is messing round with one of these, then before you completely destroy it (like mine), maybe drop T9 off (and check that the pads aren't shorted due to PCB fault - which is so, drop off FB24) and then see if there's any luck using a POE supply just in case there's a chance you can bring it back to life.

As to mine, although the 12vdc is there something else is gone as it doesn't create a ethernet link which I think is either due to the isolation transformer thing also being damaged and/or a further fault on the board with a sub power circuit (I've measured and there doesn't seem to be any lower voltage chip supplies (5v/3v etc))

N.B. To open up the unit, use a strong pin or jewellery screwdriver to undo the nuts underneath the seals where the aerials attach, there's a washer and an O-ring below that to remove and then carefully pushing the aerial connectors in to the unit slides the PCB out.

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