[sdiy] Korg SDD-3000 5 volt supply problems

[Gordonjcp]

On Fri, Nov 16, 2018 at 08:31:14PM +1000, Adam Inglis wrote:

> But, once I reconnect the transformer winding to the 5 volt supply, it glitches as before, intermittently. 

Okay, so that eliminates the transformer, the diode bridge and the
smoothing cap, and possibly the loading of the bench PSU would affect
any runaway oscillation in the 7805.  You have confirmed with your
sillyscope that the power supply is not in broad-band shortwave
transmitter mode?

> 
> I’m wondering, can transformer windings fail like this, intermittently, under load?
> 

Intermittent shorted turns?  Oh yes, it's a distinct possibility.

-- 
Gordonjcp