PowerBook 170 SM diode burnt

[justinmgs3]

Hello!

Curious as to whether anyone would happen to know the specifications of the D16 diode next to the power jack...? Kind of a stab in the dark, but it doesn't hurt to ask

The only stamping on it is "*KW", which doesn't tell me a whole lot.

I'm using a Sony power supply rated at 7.5v, 2A, center being positive, and it seems to check out fine on the voltmeter.

Also, I tested the battery for voltage (dead) and then took an ohm reading which comes to about 3 ohms - not entirely sure if that falls under a shorted reading or not, but if it does, I'm kinda assuming it had the potential to kill the diode?

Anyhoo, thanks for any help in advance!

 

[tomlee59]

The SMD decoder ring says that "KW" is shorthand for a 13V zener diode. Based on that value, and the diode's proximity to the power jack, my guess is that the diode is there for protection from reversed power connections and overvoltages. If the cathode (banded) end is connected to the positive terminal of the jack, and the anode is connected to the negative, then that cinches it.

A shorted battery won't do anything to the diode, but it can blow fuses. Check the surface-mount fuse(s) for continuity if your 'book isn't powering on at all.