Sounds like the "variable resistor" that allows for a variable speed is either defective, or has become corroded on it's switch contacts. You might get lucky with some electrical contact cleaner spray and spraying it in or around the variable speed switch. Otherwise, I'd just invest in a new transformer.
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Sounds like the "variable resistor" that allows for a variable speed is either defective, or has become corroded on it's switch contacts. You might get lucky with some electrical contact cleaner spray and spraying it in or around the variable speed switch. Otherwise, I'd just invest in a new transformer.