I have a Luna Pro F that went out and Quality Light Metric could not fix it. I did send it to Bogen Imaging, as mentioned in this thread. The problem was an IC chip that needed to be replaced, in my case. Total charges including calibration, cleaning, and return shipping was $77.80. The meter soon went out, and Bogen fixed it under warranty, very promptly. It has been working perfectly since, just as it did for the 16 or so years before.
"I only wanted Uncle Vern standing by his new car (a Hudson) on a clear day. I got him and the car. I also got a bit of Aunt Mary's laundry, and Beau Jack, the dog, peeing on a fence, and a row of potted tuberous begonias on the porch and 78 trees and a million pebbles in the driveway and more. It's a generous medium, photography." -- Lee Friedlander