Finally got the intensity problem fixed on the new (used) scope. It was a couple of bad diodes and some supporting components. I tried to get the originals, but that was not going to happen in any decent time frame.
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Trusty ol' 1N4004 diodes don't have the fancy low-capacitance, high-switching-speed of the original diodes, but they have more than enough reverse voltage and power handling. . . Hmmm. . . would they work? YES! The scope is all calibrated now, and works like a charm. Now that the brightness works I can see what the whole Inten'D thing is for (my old Heathkit scope didn't have delayed triggering). Pretty cool!
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Summary: $80 + a little elbow grease = 35 MHz Dual Trace Scope
The $80 price includes the shipping cost!
Model: JDR Instruments 3500
Found and downloaded a free manual (images scanned into a PDF). It was needed for the schematics to fix the intensity problem, but it also included the calibration procedures.
The guy who sold it was a bit of a sleaze bag (imo). He said, directly, that he wasn't aware of any problems, though he took a picture of it with the traces showing pulses. To me, that means he would have fiddled with the focus and intensity controls and seen that the intensity control had no effect.
So, it had a problem with the intensity that turned out to be two different diodes in the intensity circuit (go figure).
Now I've got a scope that probably cost >$1K new, and would cost $200-500 used in good working condition today. Not too shabby.
It came in the mail yesterday. A used, JDR Instruments, 35 MHz, dual trace scope for $80.00 (Shipping included) on eBay!
It had two obvious problems.
No horizontal positioning — I was able to fix that by following wires and traces back from the front panel.
The brightness is at full all the time — not able to fix that without schematics.
I spent a bit of time with it, and while it needs some calibration, I haven't been able to find anything else wrong. Also cool, it has a Z input in the back, which means I'll be able to play asteroids on it
The instructions on the box call for three eggs and that's what the first try used. It seemed just a little bit too cakey and dry to me.
Reducing the amount of egg made it just a bit richer and moister, but not crazy-rich. Of course, I'm using jumbo sized eggs, which may make a difference. If you're using smaller sized eggs, three is probably going to be fine. whip them thoroughly first in the measuring cup before adding them into the mixing bowl with everything else.
Finally managed to slosh enough junk around to clear the table in the foreground and then clean off the old workbench. The last time it was out from under a quarter inch of dust you needed a t-square to produce PCB layouts (see it there). The old scope smoked out as soon as I turned it on. It smelled up the whole basement.
All the bread-boarding sockets had been left completely uncovered under all the dust and in the dampness for the entire time. Nonetheless, I decided to assemble a small, experimental, logic circuit on the old breadboards and surprisingly, the circuit worked!
So, what does it mean if, while other guys are spending time and money building man-caves, you start building a maker cave? Well, you might just be a geek my friend.
The greatest man in history, named Jesus,
had no servants, yet they called Him Master.
Had no degree, yet they called Him Teacher.
Had no medicines, yet they called him Healer.
He had no army, yet kings feared Him.
He won no military battles, yet he conquered the world.
He committed no crime, yet they... crucified Him.
He was buried in a tomb, yet He lives today.
"There is, I conceive, no contradiction in believing that mind is at once the cause of matter and of the development of individualised human minds through the agency of matter. "
— Alfred Russel Wallace
Began at 50: my first time reading the Bible straight through
I have always "read around" in the Bible, reading individual books, or a sub-set of books. I've read many books many times, but could not tell you with any confidence that I have read every book.
A while ago I started reading it from front to back, starting at Genesis 1. It is interesting how you get an entirely different perspective when you read it this way. The way the stories unfold, first flying over, then getting closer in and revealing more detail. It is incredibly beautiful how all the books fit together into a bigger whole. That aspect of it was a complete surprise to me.
It has been slow going, just a few chapters a week. I am now at Isaiah. I've always loved this book, but wow! what an amazing book when read as part of the sequence of the entire Jewish Testament narrative. I'm closing in on the NT books, and though I have read them many times over, I'm wondering if their message will have the same newness of perspective that Isaiah now has.
If you're like me, and you have never read the books of the bible straight through from the beginning, I HIGHLY recommend it. It can be difficult at times (the genealogy records, and the engineering descriptions of the temple, for example), but it is worth the effort. It is very different from reading a book, or a sub-set of books from within the whole. For me, the best way to deal with those many times my attention starts to wonder, is to simply put it down, and come back to it later when I'm ready to be fully engaged (hence, the slow going).
For those who, like me, have not yet done this; when you're ready to do it you will, and you will not be disappointed.