I'm watching a lecture series on electronic theory and the instructor is talking about modeling an incandescent light bulb. He said something like "We're going to talk about a kind of light bulb that's no longer in production. You might not have seen one if you're really young. It has a *filament* inside it, not LEDs." It kind of broke my brain for a few moments.
Also, if you're looking for this sort of thing, these lectures seem really good so far. Between the basic circuits series and the electronics 1 and 2 series, there's at least 100 hours of content here. The lecturer is Behzad Razavi, an electrical engineer with a Ph.D from Stanford, so he probably knows what he's talking about! It's relatively new on YouTube, too, which explains why I didn't find it last time I looked for things like this.
Facebook reminded of that time I found Atlas Shrugged on cassette at a thrift store and *tried* to read it.
Having just put a pizza in the oven downstairs, I was looking around for my phone to set an alarm to go check it. It wasn't in the couple places it was supposed to be. Then, my eye hit on it. I picked it up, sarcastically exclaiming "Thanks, Ayn Rand." "Huh?" Said Lisa? "You know that ad campaign or whatever it is with "Thanks Obama?" Well, my phone was sitting on top of the box for Atlas Shrugged. If people can blame Obama for any number of things he didn't do, I can blame Ayn Rand for losing my phone." "Well, she does have a lot to answer for." -- By the way. Atlas Shrugged? I'm not impressed so far. The protagonists are not terribly likable. The antagonists, whether individuals or the horrible over-regulating government, are not believable. The sex is edging into creepy. She has a few moments. I got a bit of a thrill out her description of Dagny Taggert running the first train on the John Galt line, built of untried Rearden Metal, as it sailed across the desert. But that might be as much me being a train fanatic as her storytelling. In general, this feels like a big straw-man argument being set up against dumbed-down overly large government. I'm not sure how much more I'm going to listen to. (Though if I stop now, I gather I miss a riveting *sixty page speech* by Mr. Galt.... Given that this is an abridged version though, who knows if that's in there.) What I do like getting out of it it is the sense that, maybe some folks on the reactionary right *really think government is like this*. It helps me understand their position a little better.
Also, these arrived today and I can swap out the resistors on my Heathkit now! ...If I can find the right values. That's a lot of resistors! And all my little plastic parts drawers are in the states...
I cobbled together a good power supply for the iron that Mark Balliet gave me! I was having a hard time finding a barrel jack on a thrift store transformer that matched it, but eventually I bought a cheap little 7.5 volt, 3 watt wall wart with the right barrel, a Sharp power supply from something-or-other that provides almost 6 amps at 12 volts, and soldered the cord from the little one into the big one. I had to resort to a little saw on my multi-tool to get the little one open, but the sharp is in a much bigger package with press-fit snaps and screws and opened much more straight-forwardly. And actually went back together, unlike the other one!
How did I use the soldering iron without a supply for it? I found another wall wart with a jack that didn't actually insert much at all into the iron's receptacle, and doesn't provide near as much power as the new one does, but it made just enough of a connection to make it work until the job was done.
More about the Heathkit I'm trying to fix ( Collapse )
So Q1, a 2N4304 FET is no longer available and I need to either buy some from Ebay or find a replacement. Trying to find replacement transistors is a new and special kind of hell, isn't it? Especially when I don't have enough of a grasp on theory to fully know what I'm looking at.
I do have a datasheet, but I don't know how to figure out which values are critical to match and which are less so.
My multimeter showed up today! I paid about $18 Canadian including shipping, and you definitely get what you pay for. But it works, basically. The rotary switch is a little...special. So I dug into troubleshooting the Heathkit!
It has 700 microamps across the meter when turned on with no probe connections. The meter reads full scale at 20, so of course it pegs. I'm pretty sure the problem is a bad transistor, either Q1 or Q2. Q1's source is connected with Q2's base and they read more than 8 volts to ground. The schematic suggests that measurement there should be about 5 volts. So either Q2 is bad, or it's running full on all the time because Q1 is bad. I think? I guess I'll order some transistors and find out!
Also the resistor measurements are all way low of spec! Not sure if it's a flaky multimeter, or measurements in-circuit are off, or if the resistors have just drifted after 60 years or so. Once I get a power supply for the soldering iron that Mark gave me as a birthday present (*so awesome!*), I'll take one off the board and check it out.
I'm starting to see a therapist for EMDR work for trauma recovery. Danae has been doing that for a while and has found it to be the most effective form of therapy she's ever had, and she's had a lot of therapy. I'm giving it a try on her advice and suggestion. Tonight, I've spent a lot of time going through old LJ posts to find events and dates, and it's been taxing. To be expected, when I'm specifically looking for dates of things that are traumatic events and triggers, but rough. I was also reminded of how much happier, confident, and outgoing I have been at various times in the past, and that's reassuring. It's a reminder that this is something I can be and do.
---
I have a draft done of my preservation final, and now I need to do a bunch of work on the database final. I can do this.
---
Tinkering is a wonderful distraction for me. When I'm able to fix something, it just makes me feel *so* good about myself! I think taking a little time away from finals to do some of that was worth it.
And I did fix that TV! The Y-sustain and Y-buffer boards arrived on the first. I installed them and still got no picture, but the clicking noise wasn't happening either. After trying permutations of parts, it's working correctly with the new Y-main board and the old Y-buffer board. I think they may have sent me a bad Y-buffer? Either way, it's working now. I played games on it for several hours to make sure it wasn't going to die again and have now posted it for sale on Kijiji.
While I was on Kijiji, I found someone selling a Heathkit multimeter for $25. I now own my first piece of Heathkit gear! It expects an 8.4 volt mercury cell battery that is no longer made as a power supply, but it looks like 9 volts will work in a pinch. I'm going to built a power supply for it eventually. For now, I need to figure out why the needle pegs high when turned on in any settings. Probably a short? So I have ordered a cheap multimeter to fix my multimeter with!
As I carried the replaced TV through the office to tuck out of the way in the back bedroom, I looked at my computer desk and made a suddenly obvious connection. I started to get things set up to connect it to my computer.
"Is it going to replace your smaller monitor?" Asked Danae.
In an incredulous tone, I responded "No...?" I mean, why would I do that?
I scouted out the location of our garbage and recycling bins. I returned with a 46" TV that was sitting by the receptacles. Plugging it in, I found that it seemed to work well other than a bad backlight affecting the right quarter of the screen. I figured that if it's a bad inverter, it should be an easy fix and the TV is big enough for Danae and I to play split-screen co-op games on. The TV that came with the apartment was just not working. We'd considered moving it, but don't really want to have it in the middle of the room.
I laid it face down on the glass table and started disassembling, putting various screws into labeled boxes on a piece of paper for reassembly purposes. I determined the screen is edge-lit, and the back of the display panel looked quite difficult to access. Even with all the chassis and bezel removed, the panel was still connected to the metal plate that serves as a mounting for all the boards.
I turned it on again to see if I could better understand how the backlighting worked and to my surprise, it *really* worked. The whole screen lit up at full brightness. I can only assume someone dropped it or something and jostled one of the backlight connectors. I played a little bit of Super Mario Brothers on it lying on my back under the table to see if it kept working (it did), then put it back together. 69 screws from six parts later, it was standing up on the TV console in place of the 32" TV that was there before.
So, free Samsung 46" 3D-capable smart LED TV with wi-fi. Score! It has one row of bad pixels on the far right edge of the screen that I hardly notice, and the speakers are staticky, probably from being overdriven and blown. (Who plays their TV that loud?) This was a top of the line TV that cost about 1800 gbp nine years ago, and it is hands down the best-looking video display I've ever owned. The LED backlighting allows for brilliant saturated color and deep velvety blacks. I'm impressed.
I'm *not* connecting it to the network unless I can firewall the hell out of it so it doesn't report my activities to its masters. A friend told me I should make sure I turn off the functionality that sends snippets of what I'm watching on it back to Samsung for analysis. If so many companies hadn't violated privacy in so many egregious ways, it would have sounded ridiculous. I Googled and found that this was, in fact, true. I shouldn't be surprised by this behavior. I really shouldn't. But somehow, I often still am.
Company 1: "We've violated consumer privacy in the most awful way possible!" Company 2: "Hold my hidden microphone..."
Danae says she almost feels guilty about it. I do not feel guilty at all. Rather, I'm feeling quite pleased with myself.
Work is getting rid of their vintage Tattle-Tape machine and it has parts I would *love* to take home and work with, except I can't work with them right now...
Six *big* capacitors, wired in parallel. Two *huge* capacitors wired in parallel. one big transformer that looks to have more straightforward connections than the big toroidal one I have.
Also, in the giant pile of abandoned stuff we cleaned out of lockers, there was a nice stethoscope. I joked about taking up safe-cracking and Harry reminded that we have a safe. So I spent ten minutes or so listening to it and then read this. I wish I had to time to go through this process and try and open it; it looks like a ton of fun!
content
awake
geeky
excited