Quote:
Originally Posted by vortalexfan
Ok I have a question, concerning the bypass caps in this radio.
Two of the bypass caps are marked on the base of the caps and on the schematic .5 (they are two singles marked at that value) and one cap is a double cap marked 1. on the bottom of the cap and on the schematic, what's the purpose of the decimal point (.) after the 1 on the double cap? I'm assuming it's a 1 MFD capacitor which if that's the case why bother with a decimal point after the 1 on the capacitor markings?
Also how would I restuff the 1 MFD bypass caps? I ask because I think a 1 MFD 630 VDC film cap is going to be too big of diameter to fit inside the can, let alone two of them.
Also as far as the .5 MFD caps go, I'm assuming a .47 MFD 630 VDC cap will work fine in its place?
Also I was wondering how I would go about handling the wiring going to the RF bypass caps because while the rubber insulation of the wiring is still intact and isn't falling apart, it is very brittle to the point that just moving the wires just slightly causes the rubber insulation on those wires to crack and chip off the wire which if I'm going to restuff those bypass caps I would have to move those wires and I don't want to have to replace any more wiring than I have to in this radio to get it up and running.
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I'm not sure on the cap values. It's possible the double cap marked 1. is the total for the two .5 mfd combined, but that's just a hunch. You need to remember that back when these things were built the technology was still very experimental in nature. Personally I would try to baseline the radio using a dim bulb tester, then divide and conquer one component at a time. A complete strip down will only introduce more unknowns. I'd begin with the 80 rectifier removed, testing the transformer with only the filaments of the other tubes installed. Then with the 80 still removed measure between each of the two high voltage wingdings to ground. Next the 80 goes back in to see if the B+ comes up without drawing too much current. Start with a low wattage bulb and work your way up. As long as you limit the current you can't get yourself into too much trouble. At some point you'll have a better idea of where the problem areas are. I agree with leaving the wiring alone until you get all the other bugs worked out, and then only replacing a section at a time with testing in between.