'CSI' Star Jon Wellner's Wife Is Flat Broke ... Needs Money ASAP in D -

"CSI" star Jon Wellner's estranged wife is desperate for money, claiming he's completely cut her off from their cash and credit cards ... leaving her with only $70 to her name.

According to new legal docs obtained by TMZ ... Whitney Wellner is asking for emergency spousal support because she can't make ends meet after losing her job at a dog rescue ... where she made $11 an hour.

Whitney says Jon makes a fortune -- nearly $114k per year in acting residuals alone -- and she wants a piece. Worth noting, Wellner appeared on 126 episodes of "CSI" over 10 years.

But Jon says Whitney's way off base, because he took a "huge loss of income" when "CSI" went off the air. He says he's now only working on random projects.

TMZ broke the story ... Jon wanted Whitney to get a "real" job at the time of their divorce -- saying she was a lousy actress.