dave1138
07-21-2013, 12:45 PM
I have a Philco 51-T1834 set that appears to have a short somewhere in the B+. Here's what has been done: ALL of the capacitors have been replaced including the micas, the filter caps all have voltage ratings as specified in the Sams (148-13) BOM. All resistors have been checked and any out of tolerance ones replaced with ones having appropriate wattage ratings. The set played quite well after the parts replacement, logging around 20 hours of use. The vertical output transformer failed, and I installed a NOS replacement. After another 4-5 hours of use, I started getting arc-over in the rectifier tubes. I put the set aside to start on other projects about a year ago. I am ready to look at it again and I have a couple of theories to test. One is that the transformer windings may have developed a short, the other that surge voltage exceeding the electrolytics' ratings have caused them to fail. I have another Philco chassis for parts in case the transformer has failed and if the filter caps have failed I want to find caps with a higher voltage rating and add inrush current limiters. My question is, if the caps have failed, where is the best place to add the ICLs? Does limiting surges on the primary side of the power transformer affect the B+ surges or is it better to add them to the B+ line?