Bad solder joints are known to heat up and cause failure such as this.
I'd fix the solder joint and the fuse. If it's really an overcurrent
situation then the fuse should have handled it. I tend to believe it
just had a high enough resistance to get real hot and burn itself up.
--
Martin K

Jinx wrote:
> Hi all, wonder if anyone can offer suggestions
>
> Got this switchmode PSU that's not working. Attached shows the
> PCB beneath the push on / push off mains switch. The case of it is
> earthed (top left diagonal), middle pad is mains in, and the mains
> out is south-east of that. It can be clearly seen that the mains out
> pin of the switch has burned itself away from the pad, hence no
> power to the rest of the circuit. The text below the red fuse, which
> is intact, is T800mA 250V
>
> My dilemma is - 
>
> Was this a manufacturing dry joint that's slowly got worse ? Switches
> and sockets do tend to waggle on boards and break connections. If
> so, then this would seem a very simple repair. Or....
>
> Has something (catastrophic or simply regular usage) in the PSU
> caused the burn-out ? Leaving the fuse intact ?
>
> Would be interested in opinions before I stick any power up it. Oh,
> and the owners of the powered device are bigger than me
>
> TIA
>   
>
>


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