Rod, Never heard the singing. Switch room's were too noisy.
It always amazed me that those core planes were hand wired. I guess by little people. Or, big people with little hands. On the PDP 8/I they were 4K plug in affairs. Ken On Tue, Apr 25, 2023, 9:14 AM Rod Bartlett via cctalk <cctalk@classiccmp.org> wrote: > Ken, > > This discussion does my geezer's heart good. > > I used to maintain Honeywell mainframes in the late 1970s, some of which > had core memories. Tapping them on the floor wasn't an option since they > were such huge beasties but they did have space for spare bits. I've > swapped to the spare bits or replaced sense amps to fix many a core > problem. Something I'll never forget is the way the power supplies "sang" > when running memory diagnostics on the core units. I could always tell the > diagnostic was done when the singing stopped. > > - Rod > > > On Apr 24, 2023, at 2:11 PM, KenUnix via cctalk <cctalk@classiccmp.org> > wrote: > > > > David, > > > > I could tell you I had an experience where I had a stuck bit in core > memory. > > > > It was in a trunk frame in a #2ESS AIS. > > > > I removed the core package and tapped it on the floor, reinserted it and > > the trouble cleared. > > > > Sticky bit! Ha > > > > I only knew that because it happened to me on my old PDP-8/I.. > > > > Ken > > > > > > On Mon, Apr 24, 2023 at 1:50 PM David Gesswein via cctalk < > > cctalk@classiccmp.org> wrote: > > > >> On Mon, Apr 24, 2023 at 11:11:35AM +0100, Pete Turnbull wrote: > >>> On 23/04/2023 22:52, KenUnix via cctalk wrote: > >>>> Pete, > >>>> > >>>> Did the 8E have core or solid state memory? > >>> > >>> It had both, but I didn't put the core boards in the dishwasher. I > >> figured > >>> they might be too delicate for that, so I rinsed them by hand in the > >> kitchen > >>> sink. > >>> > >>> I should have said that in my original post. > >>> > >> > >> I assume your referring to the core electronics boards and didn't wash > the > >> core plane. > >> > >> I've never used the dishwasher. I've hand washed R, W, G and M type > boards > >> in > >> sink with dish soap and soft bristle brush, rinsed, then blew off with > >> air compressor, then finish dry with fan. For pots and other > >> components that I wasn't sure how well they were sealed I used damp > brush > >> or > >> cloth around them. Rest got dunked. No obvious issues from washing. > >> > > > > > > -- > > End of line > > JOB TERMINATED Okey Dokey > >
