faultfinding help with 233 micro

Started by drspastic, January 04, 2013, 07:41:46 PM

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hi, i just got my 233 micro, it all looked good so i connected a composite video projector (low voltage battery powered LCOS) to video out, and a stabilised and monitored 5v supply. i set the max output current on the supply to 500ma which should be more than enough for a test. when i switched on the supply, it tripped its overcurrent protection and i turned it off. i checked the ohms between supply pins and my meter read 3.6 ohms either way!
this does not sound good on a little board like this. can anyone offer me any fault finding suggestions? i really want to get this board working.


by the way, most of the power is going into the schottky diode by the power connector.
its getting quite hot with 5v input, and the voltage on the system test points is 1v.
is there any chance the diode has gone short circuit? if so would i be recommended to remove the diode and try to reapply power?


well i just lifted one end of the schottky and it is indeed blown short circuit.
applied power and all test points seem correct at +5 and 3.3

dont see any leds coming on though, but i have not inserted sd card yet. should i see anything with just power connected?

im still dubious as to why the diode was shorted, i double checked my power supply and its 5.02v stable from 0-500mA and no spikes on connection. maybe it was a bad diode from the start but i cant see how the board would have got past QC.

am i likely to have problems running the board without the diode, or shall i dig out a replacement?


ok, arch is now running fine. any thoughts on the dead diode? shall i replace it or just leave it out?