Questions - Setting up a SRAM board in S-100 / Altair system?

Hi Tony, On Thu, Sep 4, 2014 at 1:45 PM, Tony Duell <ard at p850ug1.demon.co.uk> wrote: Yes, I'm +fully+ aware of the integrated line filter / IEC mains socket devices. It doesn't have one, I promise you.. ;-) It doesn't. It's just a hardwired cord with the typical black Heyco grommet securing it in the case. I have experience with these instruments, I've used them to test products at a previous workplace.. There is presently no on-board switch, it's hardwired 'on'. Switching is being done at the Variac. Firstly, 'Digital circuits are built from analugue parts'. Err.. yes.. I'm not sure what your point is? :-) > Seoncdly, and more inportantly, the power supply is as 'aanlogue' as you > can get. Forget that it powers a computer, treat it like the PSU in an > audio amplifier. There is no real difference. > Again, yes.. did something I said give you the impression that I thought otherwise? If you read my earlier posts, I specifically mentioned that I had the PSU stuff taken care of months ago, as it's the sort of work I can do in my sleep.. But it +has+ been a +while+ since I worked with a PSU that was driven by such a large EI core xfmr. So I was asking if the ~85uA (that's micro-amps) of leakage I measured would be typical for iron of that mass (18lbs or so) and age. Virtually all (if not _all_) transformers exhibit some leakage - it's just the nature of the beast. Stray capacitances in the xfmr provide a coupling path for AC voltage, in addition to the other leakage paths which can develop (due to imperfect insulation, etc).