John, Thank you for your responce. I tried Tannenbaum and a couple of others without success. I was hoping that Riders or another source might have it. My trouble is that the Osc. coil heats up when I applied a battery, but I couldn't find any short. I think someone might have altered the wiring many years ago by adding a choke coil. Don't know for sure. Thanks again. Dan :Hi, ::You could try the usual sources, A.g Tannenbaum, et al. But when in doubt, replace the caps, after testing all of the tubes. Once that is doen, you should get something out of it. Then comes the issue of calibrating it, and locating a calibrated reference. :: :: :: :::Could anyone tell me where to find schematics for old test equipment? I have a Philco tester #048 and would like to get the oscillator to work. Any help would be appreciated. ::: :::Dan |