Well, Rob has posted that this model doesn't need an audio transformer and that is one less thing to worry about.
Here's a rundown on my experience with the BC-1004-C regarding repairs. I obtained the radio in 1968 and it worked fine for many years but then began having failures. All of these failures were due to shorted capacitors in the IF cans. This takes out the resistors used to supply the IF amplifier tubes. Repair is possible but not easy since these components are located inside the IF cans which have to be removed to gain access. Replacement with off the shelf caps and resistors fixed the problems.
Now that the radio is nearing 70 years age other problems have developed. The bathtub caps on the side of the chassis underneath began leaking and shorted. Look for oil on the bottom cover. The fix is to leave them in place but disconnect them and install new axial lead caps of the same ratings.
Many of the molded resistors, especially the higher power ones, have changed value but surprisingly the radio still works despite this. It is a good idea to replace resistors which are out of tolerance.
Surprisingly, many of the tubes are original and they still test and work fine.
My attitude is that it is worth some time and expense to keep these radios working, not only for historic nostalgia, but they are fine receivers. That's why I posted some of the problems to look for hoping it will help with troubleshooting.
Neil
You guys make me wish I never got rid of my HQ-140X. It was my first "real" receiver as a Novice and General. Then I went into the Navy and I let it go. I loved the way shortwave sounded on it. Nothing like that today.