[sdiy] Korg SDD-3000 5 volt supply problems

[Oakley Sound]

The first thing I would do is measure the current that the 7805 is 
supplying to the digital board. However, this may mean you have to break 
the wire carrying the +5V to that board. There is a possibility that the 
digital board is taking too much current and causing the 7805 to go into 
current limit. This would suggest a fault on the digital board somewhere 
- a decoupling capacitor is the most likely culprit.

That said, it may be the 7805 itself that has gone faulty so it may be 
just easier to replace the 7805 in the first instance.

Tony

www.oakleysound.com