12-31-2016, 12:47 PM
I have been working on the Philco 90 for the last couple of weeks, burning up a little vacation time. So far, I re-stuffed all the bakelite blocks and replaced all of the resistors that were out of tolerance. The primary of the first detector transformer was open, so had to rewind that.
That said, when I went through the alignment, the IF tuned up just fine at 175 kHz. When doing the RF portion of the alignment, both ends (600 kHz and 140 kHz) peaked, but I find the high end to be noticeably weaker than the low end of the band. Is that normal for one of these receivers?
When checking the tube socket voltages, what is the correct meter ground connection point? Is the chassis the correct reference point, or the transformer center tap of the rectifier plate winding? The Philco service literature I have does not state a reference point, it only refers to an AC Set Tester.
Thanks
That said, when I went through the alignment, the IF tuned up just fine at 175 kHz. When doing the RF portion of the alignment, both ends (600 kHz and 140 kHz) peaked, but I find the high end to be noticeably weaker than the low end of the band. Is that normal for one of these receivers?
When checking the tube socket voltages, what is the correct meter ground connection point? Is the chassis the correct reference point, or the transformer center tap of the rectifier plate winding? The Philco service literature I have does not state a reference point, it only refers to an AC Set Tester.
Thanks
Chris H
N9WHH
