Mystery diode "4L"

Andrew Mawson · 2013-05-02T16:31:26+00:00

Any electronics whizzes recognise an axial diode slightly smaller than a 1N4001 bearing just the marking "4L" along with a blue cathode band? It's used in a switch mode power supply of 1993 vintage running at around 25kHz. No other clues I'm afraid. AWEM