On 12/5/21 3:24 PM, Ethan Dicks via cctalk wrote: > This would be really cool as a debugging tool > more than just as amazing lights.
A great lead-in to my story. I was working away on the RK11 implementation in the QSIC and when I felt like taking a break but still wanted to get something done, I'd work on the indicator panel. Of course, the indicator panel ended working before the RK11. Just having 144 lights that I could assign to any purpose was useful but then came the day when the RK11 was mostly working. I loaded up an RK11 exerciser program that Noel wrote and just sat back to bask in the glow of the blinking lights. It was a good feeling. Then I noticed something that wasn't right. Even though the exerciser was working, I saw a pattern in the lights that showed up a bug in my implementation. I'd really only implemented the indicator panel because I thought it was fun but it lead me to a bug to fix right off. Here's a short video clip of the indicator panel in operation and showing that bug. I'll leave this for a day or two (or until I remember again or someone asks) and then say what it is I saw. I think anyone with a reasonable familiarity with the QBUS will be able to pick it out though I'll say that "Latched Address" is the address "half" of the data/Address Lines, that is the value of those signals when SYNC is asserted. http://pdp10.froghouse.org/qsic/ip-full.mp4 > P.S. - not to derail things, but definitely loop me in on the (future) > thread for making reproductions. I have access to some tools that > might make parts of it easier. The inlays are mostly not done with any tools I have. I do the graphics with Inkscape. Rod made up the blanks with silk screening. Then I have the white printing done at a printshop I found who has a large, flatbed printer that can print white ink. I do have some ideas about how I might try to make up blanks with a laser etcher I have access to but at the moment we have an ample supply. Also, I've experimented with making my own bezels out of PVC board from Home Depot using a CNC router. In the pictures below, the yellowed bezels are old DEC bezels while the white ones are ones I made. I figured that if we ever get the QSIC shipping and people want indicator panels (I hope they'll want indicator panels), I'd rather not depend on them ripping apart old DEC bezels to make this work. Anyway, I'd be most happy to have another person with more tools to help build bits and pieces of this stuff. I've noticed that as I gained access to different tools, I came up with different ideas about how to make things. I didn't think the laser etcher was all that useful until I started using it. Now I want to use it for everything. Turns out it can't quite handle 3/8" Delrin; it just melts it and makes a mess. Speaking of help, if anyone wants to review the QSIC design, I'd welcome that. This is by far the most complex circuit board I've ever designed. Back to indicator panels, here's a picture showing a bit of the evolution of my indicator panels. The video above shows it really early, when I just taped a paper inlay to the circuit boards. Then the bottom panel in this picture is taping that paper inlay to an MDF light shield. The top panel is using one of Rod's blanks with paper labels taped to it. And then the third panel down is a printed inlay like we're talking about now for the RK11-C. The second indicator panel is a TC08 inlay that I borrowed from Noel to use as a model as I worked on the graphics for our own. http://pdp10.froghouse.org/qsic/indicator-panel-stack.jpg Here's a close-up of the TC08 and our printed inlay. I'm rather pleased with how it looks, I have to admit. The only real thing I'd like to change is the gloss. Somehow, DEC's inlay is as flat as flat can be. There is no glare to it whatsoever while ours are quite glossy. I've looked at frosted acrylic and it's a little better though really it just diffuses the glare, it doesn't eliminate it. I've also tried some spray-on frosting which helps a little but it also has a tendency for its solvents to melt the printing that's already there so that's a bit fraught. http://pdp10.froghouse.org/qsic/indicator-panel-printed.jpg Dave
