repairing 9v lights

[Lego Otaku]

Over the years I've picked up several lights from various light and sound sets in '90s through early 2000. 2 of the lights, both 1x4 brick with 2 bulbs, are not working.

One of them one bulb seems burned out, it never lights up. Other one only works in flashing mode, never lights up when I rotate it 180 degrees for steady mode. I can live with non flashing piece but a 1x4 brick with 1 dead bulb is just ick.

So any idea about repairing them? Or should I replace em with flashing 3mm LEDs (and current limiting resistor) for long life? I tried Google but kept getting useless result such as repairing Malibu tail light (yes I used Lego in search, don't see how Malibu car is connected )

[LEGO Guy Bri]

I'd try going with LEDs or buying a working one from Bricklink. Best of luck