PT-80 Crash-- what should I check first?

[rik]

My second project I built was PT-80 Delay. I didn't substitute any parts. Once I had it all together, I got a 24v AC power supply instead of DC, and got nothing but hideous noise from the circuit. I spent weeks troubleshooting running it with this incorrect supply, even reversing the diode on the power supply because I thought I might have had it backwards.  I'm fairly certain that up until I plugged it in, the build was probably ok-- I've gone over it many many times.

I've built several boxes successfully since, and am ready to revisit my build and try to get it working, this time using a dc power supply. I imagine I'll need to replace the diode where the power goes in, what other parts are most likely to have been blown up by my mistake? I assume the caps and resistors are probably fine, is it a given that I should go ahead and replace the chips and transistors? 

[mike darling]

Check the DC supply voltages going to all semiconductors (regulators, transistors, opamps, 571, etc.). Double and triple check the polarity on any diodes, electrolytic capacitors, etc.

-mike

[Mark Hammer]

This is one of the reasons why few people here would ever recommend the PT-80 asa first project.  When analog goes wrong, you can often hear audible cues that signal what the problem might be.  When digital goes wrong, "hideous noise" is not exactly the most diagnostic sound in the world.

A 24v supply?  I'm assumping this was appropriately regulated downwards to provide the right voltages for the components? Keep in mind that digital stuff like the PT2399 does not want to be within 20 miles of anything higher than 5vdc.

[rik]

Assume away. 

The bill of materials said to use an 18-24v DC supply, and the circuit has both 5v and 12v regulators, so I think it's designed to handle it.