The supply voltage coming from the bridge is for all lamps. If it had issues, it could not selectively burn out specific bulbs. In other words, there is a specific reason the pop lamps only, are burning out.

I believe that the pop bulbs in EK are controlled lamps... You could try a different lamp driver board, if you have a spare. Or, track down the transistors on the lamp driver board that run those lamps and test them.

I would replace the bulbs and go in to lamp test and confirm that they work for 20 minutes-cycling back and forth, and then report back here if they are functioning after 20 mins.

Then I would say unless those bulbs are running VERY bright, that the actual pop's downward movements are causing the bulbs to fail. Try a different brand. I have a very similar problem with my Stern Ali... I use old EM bulbs from the 50's in those pops and they last a LOT longer than the Chinese bulbs of today.

Yes, but if you want to specially just add them to the pops, you only need to solder a single 470 ohm resistor across each bulb's circuit. Or, there could be specific LED bulbs that address these issues on the market already, that add the required resistance... I haven't shopped for LED bulbs in a while so I can't say for certain.

The other more pricey option is to buy a NEW Bally / Stern Lamp Driver Board with LED support from Weebly... https://nvram.weebly.com/new-pcbs.html

I think they are $90 shipped. He also has the "Pinside" linked business.