@shorling posted:The vendor must have sold tens of thousands of these direct replacements. If there was a fundamental design issue I suspect they would have been out of business a long time ago. My issues in my previous post were all application related.
Just because they've sold thousands doesn't mean there isn't a basic design flaw. 
Lots of products have major flaws, yet massive quantities of them are shipped before the flaws surface.
The diode is a basic precaution running LED's on AC voltage, the reverse voltage rating of most LED's is around 5V peak. A 10 VAC source has a peak reverse voltage of 14 volts to the LED, almost three times it's rating.
Once again, though you should expect it, Stan is spot on with his analysis, they needed the diode.
@GregR posted:Will a 1.0A diode be good for a string of 3 LED bulbs, or would each lamp require a 1.0A diode? I'm the wrong kind of engineer for making these calculations.
Yep, unless these are REALLY high power diodes, the 1A diode is plenty. 
