First off, I'm going to use 300B tubes. My PWR tranny is the Edcor XPWR124-120. Primary= 120V,😕 Secondary = 640v CT at 150ma, 6.3v CT at 4A, 5v at 2A. This is said to be under load. I have at the Brd on T1-1=Grnd, accross T1-2 and T1-3 =5.004v, T1-4 to T1-5= 678v, T1-4 or T1-5 to Grnd=338.5v, T1-6 is not used on the 300b, across T1-7 and T1-8 =7.15v, and T1-7 or T1-8 to Grnd = 3.98v. Now with the rectifier tube in and warmed up I have B+=467.7v, B-=.001v, 300b filament=4.95v, 5842 filament =9.09v, that is with no load on, or no tubes in other then the 5ar4. Why don't I have any B- voltage? What should I be looking at? I've buzzed it out and checked for shorts over and over again. I just don't understand where B- is. I don't want to put any other tubes in place until I have this figured out. Thanks for any help.😕
No B-
Well, the schematic is for the Tubelab SE. It's on the sight. On the schematic it say's something like -100v, or -150v. It's very hard to read, it's so small. Thank you.
Well, the schematic is for the Tubelab SE. It's on the sight. On the schematic it say's something like -100v, or -150v. It's very hard to read, it's so small. Thank you.
I may have solved my problem. Started checking parts in the B- rail. There aren't many. After checking the FRED's, I pulled R5. A 270 ohm Mills 5 watt. Guess what ! It was dead. Or when I could get it to read, it measured in the mega ohms. So I called Sonicraft, and told him one of the resistors I bought was bad, and I needed a couple more. He was nice about the transaction, but I didn't get a" sorry the part I sold you was bad "or anything. Just that there would be an extra surcharge because my order was under $25.00. Like I said, he was very nice as usual, But, call me crazy, I would of appreciated a sorry about that, or I'll wave the surcharge since it was our faulty part. Guess I'll look else ware in the future for my Mills resistors. So, anyway, I'm having them sent Priority mail, so I'll have them in a few days. I'll let you all know how it turns out. Thanks again.
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