[NTLK] Recurring failure on eMate300s (DZ1)

[Sylvain Pilet]

In my stock I have several eMate that are affected by the same failure. It is apparently (I say apparently because I'm not sure) a 9V transition suppressor Zener Diode (the KV motorola marking) which is just after the power connector. It is possible that these diodes may have burnt out after connecting a non-compatible power supply, I don't know, I don't know the history of these eMate. They have been heated so much, that the printed circuit board has been well cooked just underneath. The problem is that I can't find this reference at the current dealers. 
Would any of you know more about this diode than I do? 
Moreover, but I'm getting out of my electronics skills, it's possible that the reason of these failures is actually elsewhere on the eMate motherboard.


See the pictures of this diode and the eMate300 motherboard:

Translated with www.DeepL.com/Translator (free version)

Diode (DZ1) 
http://message-pad.net/Medias-publiques/eMate300-Electro/M704-KV-eMate-300-2.jpg
http://message-pad.net/Medias-publiques/eMate300-Electro/M704-KV-eMate-300-3.jpg

Motherboard
http://message-pad.net/Medias-publiques/eMate300-Electro/M704-KV-eMate-300-4.jpg
http://message-pad.net/Medias-publiques/eMate300-Electro/M704-KV-eMate-300-5.jpg