  We study the behavior of the tail probabilities $P(V^2<r)$ as $r\to 0$, where
$V^2$ is defined by the following double sum $$ V^2
=\pi^{-4}\,\sum\limits_{i,j\ge 1} \Big((i+b)\,(j +
\delta)\Big)^{-2}\,\xi_{ij}^2,$$ where $ \{\xi_{ij}\} $ are independent
standard normal random variables, and $b$ and $\delta$ are constants: $b>-1,\
\delta>-1$.
