DDS function generator

This DDS function generator was supplied without a power supply or case. I quickly blew it up!

This little board only function generator was purchased because it was cheap, quicker and easier then locating a function generator schematic and building one from scratch.

Initially I built a little card board enclosure for it. Without much use it got put away. Then one day I dusted it off and brought it out to play. Then I noticed that the display was working but the selection of frequencies was only showing 10hz steps rather then 1hz increments.

lacking any schematic I set about trying to repair the item and took pictures of various parts of the circuit.

It seems most likely I plugged in a power supply with too much voltage and took out one or more of the integrated circuits.

I noted that one IC7660S-CPAZ was socketed and that integrated circuit was available online and had a data sheet. This showed it as a voltage regulator that can be used to provide duel rails and can also be implemented as a voltage doubler. I ordered a bunch of these and was pleased to see that replacing it resolved the issue.