By a stupid mistake i managed to hook up my Tomtom XXL GPS to 12v and blew a SMD diode on the pcb.
I borrowed a XXL from a friend and could see the diode was marked B, but i could not find any info on that particular SMD diode. On the working unit the voltage across the diode was measured to 4.58v.
The unit with the blown diode would not turn on but the power light turns on (green led in the bottom of the GPS)
Could someone help me to identify this diode or suggest a equivalent replacement?
I would guess a 4.7v zener.
But that's just a guess.
I suspect that it is a 5V TVS diode. These usually go short circuit when they experience an overvoltage. Is it O/C or S/C? Normally you should be able to remove such diodes without affecting the operation of the circuit. There appears to be an inductor between the 5V USB supply and the cathode.
With the diode removed measure the impedance across the pads on the PCB
(Ensure it’s not used a zener to produce a crude voltage reference)
Then try with the correct power supply