Satyrnine Posted May 25 Report Share Posted May 25 (edited) Last CFA board has spicy bias. With bias pot all the way down, I get about 150ma across the 1R's. That can't be right. The rest needed to be set around middle to get any idle current at all. Rechecked my P's and N's, and resistor values. Any thoughts? Suspect the middle (bias driver?) 15030? 🤔 Edit: replaced the middle 15030 with a slightly lower hfe version, dropped minimum bias to 120ma or so, so not the culprit. And then I shorted legs with my probe again like an idiot and popped the "last" 30/31's again. You'd think I would have learned something. I need probes designed for this clearly. Here's latest chassis face design: The horizontal lines would be deep machined grooves. Edited May 25 by Satyrnine Quote Link to comment Share on other sites More sharing options...
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