if you pull down that trim, you will find the old can is still there. these "retro fits" simply screw into the old existing socket. just go buy regular LED bulbs. and replace the trim.

Can't see a way to access the bulb

LOOK IN THE CAN THERE IS A SOCKET IN THE CEILING THAT WAS SCREWED INTO. YOU HAD TO UNSCREW THAT FROM THE SOCKET TO REMOVE IT . YOU ARE HOLDING THE BULB IN THIS PHOTO NOW RE TRACE YOUR STEPS, AND LOOK AT THE RECESSED CAN HOUSING ......... THAT IS WHERE YOU SCREW IN THE NEW LED BULB. BUY A NEW BAFFELL AND TRIM.

"Anyone know of a more modern recessed led fixtures, smaller, that I can replace dim bulbs, not entire fixtures?"

1. After removing the fixture (which you've done) measure the diameter of the housing (sometimes called a "can") in the ceiling.

2. Purchase trim that fits the housing. Common housings are 4" and 6". Examples:

• E26 Series 6 in. White Recessed Ceiling Light Full Cone Baffle with Self Flanged White Trim Ring
• 4 in. White Recessed Can Light Baffle Trim

3. Purchase the appropriate bulb for the housing and trim. Example:

• PAR38 LED bub for 6" trim above

4. Screw the bulb into the housing.

5. Push the trim up into the housing.

With your follow up comment, it sure sounds like you want to replace the actual Diode of your retrofit housing. That can not be done. You have to buy another of the exact same retrofit fixture and install it as it was before, hopefully you can find a matching one. That is the downside of LED retrofit fixtures.

First switch out one of the other fixtures to make sure it is not something other than the fixture.