Hi Andrea, I assume that's a message for me about my strange grounding issue?
I'd already replaced the caps in that startup circuit, it's one of the first things you do when troubleshooting a non-booting Newbrain. In this case it seemed to be some electrolytic spill from the original leaky caps that I'd missed when cleaning the first time - the traces for this circuit are on top of the board and I'd only cleaned the solder side. Cheers :) Adrian On 29 September 2017 at 13:07, shadoooo via cctalk <cctalk@classiccmp.org> wrote: > Hello, > explanation is easy. > Old electrolytic will have a bigger current leakage, i.e. the unwanted > amount of current which flows through it. > With resistances having high value, the small current is completely eated > by the leakage, thus never charging the capacitors. > As you are connecting the probes, each having around 1M ohm impedance, you > are lowering the effective resistance, thus charging a little. > > Solution: replace both capacitors with same value. > > Andrea > -- adrian/witchy Owner of Binary Dinosaurs, the UK's biggest home computer collection? www.binarydinosaurs.co.uk
