That worked! Thank you so much.The 120V reading on the "disconnected" voltage converter power feed could be due to leakage current in the circuitry. Semiconductors can have some counter intuitive behavior. For example, if you disconnect the element and turn on the element enable switch/contactor, the element firing light comes on even when the SSR is off. This is due to leakage current thru the SSR, and is normal behavior.
The fuse blowing could be due to "inrush" current when the power supply is powered up. The inrush current can be much higher than the steady state operating current. I would try replacing the fast blow 1A fuses with slow blow 2A fuses. These fuses should not blow due to the inrush current.
Your power supply may not be bad. Try the slow blow fuses before giving up on it.
Now, one more thing. In mashing mode, when the measured temp has reached the set temp, the green light on the DSPR120, flashes and then turns off, as expected. However, the heading element remains on and continues to heat the wort (actually just water right now). Should I assume that the SSR is shorted closed? I have checked the wiring and it is correct. And, yes, I have a cheap SSR without an LED.