[sdiy] Arp Odyssey 2 dead PSU

[Graham Atkins]

Antonio,

On 29 Nov 2009, at 17:10, Antonio Tuzzi wrote:

> Solved!
> (and more...)
>
> was a transformer failure of a special kind...
>
> I tested the diode bridge as suggested by Micheal,
> But everything was fine
> and ok were also the 2n3904 and 2n3906
> and so the power transistors...
> (and the tantalum caps)
> (I was going to change the ua723...)
>
> inspecting the board fror the foil side i discovered the GND track
> from the the main GND to the Rail GND was interrupted, seemed like
> FUSED!
> (maybe a power surge when the synth unattended ? Don't know!!! How can
> happen something like that)

The capacitor must have caused a momentary short circuit drawing maximum
current from the supply. It sounds like the PSU can supply more  
current than the
PCB tracks are designed for (A bit worrying) causing it to break at  
its weakest point
like a fuse as you say.

Graham