I finally bit the bullet yesterday and got around to rebuilding my L-4BPS and L7PS supplies, one with a Heathkit Shop board and the other with the Harbach version. Both procedures went well, with the second going a LOT faster than the first! I will be rebuilding a friend's L-4BPS next week and figured I could minimize the time to do his by working out the bugs doing mine.
As my L-4B is my main amp, and based on Evan's note to me a few years ago, I went ahead and changed out the 5K 7W resistor with the 13W version, replaced the 0.82 ohm HV line resistor and the 50K 50W bleeders as a precautionary measure. In the other amp I guess I was just lazy and simply installed only the Harbach board. Now sitting here thinking about it should I go back and just get it over with and replace the resistors in the L7PS? Has anyone ever had a bleeder go bad? Or the others for that matter. Sure, age will wear anything down. Also, the Harbach board doesn't include the diode balancing resistors that Mike's board does...as the original Drake diode strings used 'em what exactly is the difference? Do modern (read that "better") diodes still need that protection? I'm just curious. I was pretty impressed that my 32 year old L-4BPS kept going like the Energizer Bunny all these years and I didn't notice any deterioration at all on the bodies of the orange electrolytics....but, better safe than sorry and I'm looking forward to many more years of reliable operation with both amps. Thoughts? Dino KL0S _______________________________________________ Drakelist mailing list Drakelist@zerobeat.net http://mailman.zerobeat.net/mailman/listinfo/drakelist
