That looks like a Korean knock off of a 5D diode which I would be replacing wih a 1N4007 .
Confirm if that casing diameter is being in the order of 3.1750 mm, since I can only comparison reference to its leads.
Also take DVM and use its diode function test to confirm its not shorted and that its Vf is then testing in the proximity of 700 mV
73's de Edd
[Mod edit mV milliVolts, not Mv Megavelocity
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