[HECnet] No connectivity to arsgea 4

On 1/22/21 12:36 PM, Johnny Billquist wrote: I can tell you from experience that there definitely is. I've worked on computer equipment a very wide variety of manufacturers. By far the highest-quality by most measures has been IBM, with DEC and HP following close behind. Nothing else even comes close. Note that I'm only talking about minis and mainframes here. That would be very unusual. Field service guys carry boards for a reason. When I was running VAXen commercially, we had several boards fail in our production machines, and they were replaced by DEC field service personnel. The machines were VAX-11/750s, MicroVAX-IIs, and MicroVAX-3s. When that happens, the problem usually turns out to be dried-out electrolytic capacitors in power supplies, and occasional popcorning of small dry tantalum capacitors. Load, or lack thereof, makes no difference with the most common failure mode of the BA23 power supply. The safety capacitors across the line always see the same line voltage. Their flaws are aggravated by humidity in the air, not load. In fact, running the power supply under heavier load actually improves the safety capacitor situation due to "bake-out" effects on those capacitors. Of course such elevated temperatures then shorten the life of the other capacitors, so.. FYI, the safety capacitors in the BA23 power supply are: Refdes App C Class Lead Spacing -------------------------------------------------- C101 line-line 0.47uF X 25mm C102 line-ground 0.22uF Y 20mm C201 line-line 0.1uF X2 20mm Yup, and this is something we deal with all the time at the museum. We obviously cannot keep all of that hardware running all the time. During times of sparse tours (pandemic..), we rotate through the machines and run them for a little while every few weeks. Yeah, they started dying 20+ years ago. Awful. -Dave -- Dave McGuire, AK4HZ New Kensington, PA