According to Franklin D. Roosevelt's second fireside chat, what did he ascertain as the underlying problems facing the American economy and society in 1933 as well as the underlying reasons for the Great Depression?

Franklin D. Roosevelt opens his Second Fireside Chat by detailing the conditions which had earlier plagued the United States. He states that "the country was dying by inches." He proceeds to speak about a crisis for America's financial institutions as well as the ripple effects caused by that crisis, by which those financial institutions "were foreclosing mortgages, calling loans, refusing credit."
Later in that same speech, he details the still deeper factors which led to the financial crisis. For Roosevelt, the Great Depression had its roots in economic mismanagement coming out of World War I. As he states:

We found ourselves faced with more agricultural products than we could possibly consume ourselves and surpluses which other nations did not have the cash to buy from us except at prices ruinously low. We found our factories able to turn out more goods than we could possibly consume, and at the same time we were faced with a falling export demand. We found ourselves with more facilities to transport goods and crops than there were goods and crops to be transported. . . . The people of this country have been erroneously encouraged to believe that they could keep on increasing the output of farm and factory indefinitely, and that some magician would find ways and means for that increased output to be consumed with reasonable profit to the producer.

Ultimately, Roosevelt is deeply suspicious of laissez-faire economic practices, which would leave economic decision making to the private sector. For Roosevelt, government needs to play a role in the economy. For a government to do otherwise would amount to irresponsibility. This perspective, for Roosevelt, is vindicated by the developments that led to the Great Depression in the post-war years.

In his second fireside chat, delivered on May 7, 1933, Roosevelt discussed the need for an alternative plan for the economy. He believed it would be too much of a hardship for the American people to have to face the continuing uncertainty of mortgage foreclosures, bank failures, and the further collapse of businesses. As he put it, not interfering to stop the widening economic collapse would involve

not only a further loss of homes, farms, savings and wages but also a loss of spiritual values—the loss of that sense of security for the present and the future so necessary to the peace and contentment of the individual and of his family. When you destroy these things you will find it difficult to establish confidence of any sort in the future.

He outlined an alternative plan that Congress, both Republican and Democratic, had approved. First, it called for the federal government creating 250,000 new jobs for the unemployed through the Civilian Conservation Corps. Second, Congress approved a program to use federal funds to develop the Tennessee Valley. Other legislation included mortgage relief for people faced with foreclosure and the release of half a billion dollars for the immediate relief of people hurt by the Depression.
FDR continued by saying the task would not be easy, but the foundations of the economy had to be restored in such a way that there could not be a repeat of the same disaster that led to the Great Depression.

FDR’s Second Fireside Chat was designed to update the American people about what had been happening since the First Fireside Chat was given about eight weeks earlier. FDR believed a fundamental issue facing the American economy in 1933, which contributed to the start of the Great Depression, was the lack of money in our economic system. Banks were foreclosing on properties and hesitating to give loans because they faced significant financial issues. As a result, business activity declined greatly, which had a very negative impact on the economy because people lost jobs and had little income to spend.
FDR outlined the actions that had been taken or were about to be taken by Congress to help stimulate the economy. The Civilian Conservation Corps was created to provide jobs to young, unemployed men to work on conservation projects. Help was about to be provided to farmers and homeowners who were struggling to pay their mortgages. FDR hoped this help would reduce the number of foreclosures that were occurring. The federal government was going to provide money for relief programs that would help local communities give assistance to people who needed it. This assistance could be in the form of jobs or in helping people with basic needs such as food. FDR also wanted to help farmers get more money for their crops and was willing to hire workers for various construction projects.
FDR wanted to inform the American people that the American economy was beginning to improve. He also wanted to let the American people know that the federal government was working to alleviate the hardships caused by the Great Depression and would continue to do so.