APM-200 DIY LED bulb conversion

[eizner23]

I am replacing dead bulbs with SMD Warm white LEDs rated at 3.2v 20mA
Managed to solder the diodes and leads together after many trial runs.
Tested good with 12vdc with 330ohm limiting resistor.

Now original bulbs ran on 12v ac. I understand it's not necessary to rectify to dc but there maybe flicker. should I use a 1N4007 diode in series as a half- wave rectifier before the resistor?

 

[ivandezande]

If you can't see the flicker I wouldn't worry, but if you want to do it right and there's space, I would use the diode you mentioned and a smoothing cap, just like a 10uF or something.

 

[eizner23]

I don't see any flicker. Runs cool after 2 hrs. Typically I'd make bridge rect. but not much room to mount a small PCB board.
Changed to a 150ohm resistor as both meter bulbs ran in series.
Looks evenly dispersed.



Here is what I did in case someone else wants to try.