which part of my psu did i trash?

[creekree]

hello all,

so i finally found some time to work on my x0x.
i connected my psu to the mainboard for the first time.
i calibrated the psu a couple of weeks ago to get 5.333V - it worked like a charm, so i just soldered the psu to the mainboard and gave it a go.
nothing happened.
found out that i had used a DC walwart (oops) and tried again with a 9V AC one, rated at 500mA.
yikes! to my excitement some LEDs lit up and i was ready to play in keyboard mode... i thought.
no sound on the phones - sequencer section seems to work, though, as far as i can tell by pressing buttons and looking at the LEDs.
measured voltages at J4 again - AHA! 0,7 and 1,6V???? where did my 5.333 go??
so, i guess that there is no sound because voltages are far to weak on J4.
what did i trash?

[moogah]

Re-do the steps for assembling the PSU section first. Check the outputs of the regulator and the diodes.. Thats really all there is to fry there. If those are fine replace the caps.

[creekree]

regulators, diodes and caps are fine.
i found out that the psu itself actually is ok: when i disconnect J4 i get 5.333v, when i connect it to the mainboard, the voltage drops to 0.7 and 1.6.
so i think the problem is on the mainboard.... any ideas?

[adafruit]

yeah. you have a short on your mainboard dragging down the supply. this sort of problem is virtually impossible to debug.
basically this is why you should build stuff in sections.
maybe, if you're lucky, its just that you swapped two parts or put something in backwards.
if you're unlucky, its a bad part.
so go through every section and find out what parts you mixed up or put in backwards.