the platonic ideal

Monday 28 July 2008 at 08:30 am My vauge memory of undergraduate philsophy class was that there's the idea of a "platonic ideal" of something; that unattainable perfect example, of, say, a table. I've been similarly facinated with the a similar idea related to production of something. When you build a prototype, there are almost always things that need to be fixed for the first production run. And often when something is being produced or manufactured, there are small corrections as the manufacturing process gets smoothed out. So in manufactured things, the "real" version is the one far enough into the production run that everything is being produced consistently. In building low or single instances of something, there's an interesting dichotomy that's similar to the Platonic ideal idea. You often build an engineering prototype of something to get the functional aspects correct before building the real thing. Once you get the prototype laid down, then you buid the real item. The dichotomy is that the real item is one layer farther removed from the ideal because it's a copy, but often the engineering prototype was built in such a way that it cannot substitute for the final item. I've fixed enough trivial stuff in my beetle that it's time to get down to brass tacks and actually fix the engine. I had fun working on the brake warning light, but now I have to face the fact that something is very wrong in the right side cylinder head in the engine and I need to replace it before I drive the car cross-country. To do that, I need to remove the engine. Since I've never done this before, I'm being overly paranoid about preparations. Different people use different strategies for getting the engine out of the car, and I'm not really sure how delicate the bottom is, and I'm concerned about what could happen to the bottom of the engine if it's jacked wrong. So I'm bulding a wooden pad that will sit on the jack and support the engine, hopefully more gently than the steel jack saddle would. Here's the bottom of the engine. <?php csdnimage("jacking00.jpg"); ?> In the middle is the oil sump plate, which is pressed out of sheet steel and I don't really consider a structural part. And the edges and the center of the engine block stick down a bit, but in the middle there nice flat areas that I think are reasonable to use as support. So first I made a cardboard template to get the dimensions about right: <?php csdnimage("jacking01.jpg"); ?> The cardboard template <?php csdnimage("jacking02.jpg"); ?> is what got me thinking about the platonic prototyping thing. When I was thinking about making the pad, and designing it, the carboard piece was what I was thinking about and using. However, it can't be used for the final product. Here's the partially complete final item... <?php csdnimage("jacking03.jpg"); ?> The good news is that it fits on the bottom of the engine just fine: <?php csdnimage("jacking05.jpg"); ?> However, the whole idea of this piece is to lower it onto the engine cart, so it has to fit through the center of the cart...which it doesn't quite. <?php csdnimage("jacking04.jpg"); ?> So I'll have to trim the sides. Not bad, though, for something that was an idea in my head 24 hours ago.

Labels: beetle, jacking

don't worry; I won't let it go to my head

Wednesday 16 July 2008 at 9:49 pm I finally got the brake system warning light in my beetle back to something like working condition. In the photo below, I have turned the key to "on", so the two red warning lights at the bottom of the speedometer are on (left side of the photo). What's new is that the brake system warning light, which tells you if you have lost the fluid in one of the brake circuits, is now working and thus is lit up to test with the other lamps. It's in the upper right part of the photo, just to the left of the headlight switch. <?php csdnimage("bwl03.jpg"); ?> A major amount of work to score a minor victory--but as a result there are several more electrical circuits on the car that I've crawled through.

Labels: beetle, electronics, wiring

Doctor Henry would be proud

Wednesday 16 July 2008 at 10:44 am One of the things about my Beetle that hasn't worked and really bugs me is the brake system warning light. I'm not sure why this has obsessed me so. It's a minor system after all. I guess it's a little bit like getting into playing Lemmings; it should be so simple, so you spend way too much time trying to make it work. I placed a classified ad on the TheSamba VW site (a fantastic Volkswagen resource by the way), and someone taking a beetle apart sold me one. I didnt' want to go soldering on the only one I had. The light housing is basically a cylinder with the light at one end and connectors at the other, but here's what the innards look like: <?php csdnimage("bwl00.jpg"); ?> Starting shortly before my car was manufactured, VWs had "transistorized" brake warning lights. The transistor is circled in purple here. I guess the improvement was that you didn't need to press on the light to test the bulb, instead the light comes on when you turn the key to "on", like the other warning lights. Unfortunately, it turned out that the components that formed the two circuits in the light (one for warning indication and one for power-on-test) were far less reliable than the bulb itself. To fix it, I needed to figure out how it was supposed to work. With a magnifying glass and an ohm-meter, I figured out how the wiring was supposed to work. Here's a diagram for those of you into that sort of thing: <?php csdnimage("bwl01.jpg"); ?> The labels in circles (15,K,31,V, and 61) are the labels on the connectors at the back of the warning light housing. Where I've labelled "tap" is a metal stud on the back that isn't meant to be hooked up in the car but is useful as a diagnostic tool when you have the light out of the car. (To keep this post blogg-ish, I will relagate the explanation of this circuit to my full write-up). This was my reverse-enginneering of the bulb, but before I went soldering on stuff, I wanted to make sure I wasn't hallucinating. So I wandered down to Radio Shack and got a pack of NPN transistors and resistors suitable for duplicating this circuit. After reading on-line and resurrecting my dim memories of electronics class (1994-ish), I go this circuit to work properly. <?php csdnimage("bwl02.jpg"); ?> Again, the transistor is circled in purple. So I removed the old transistor, soldered in the new one, and hooked it up to the car, and it works. I'm currently in the process of getting the red lens for the light into a shape that will stay in the light, and then it will be done.

Labels: beetle, electronics, wiring

it was under the couch the whole time

Friday 04 July 2008 at 11:55 pm I used to watch many more movies than I used to. For whatever reason, both in my reading and TV watching, for the last several years I've been much more into non-fiction (with my watching of the current BattleStar Galactica being a notable exception). When I still watched movies a lot, my sister pointed me to Metropolis, a 1928 silent film that was a huge sci-fi classic. The movie's initial reception was poor, so it was edited down to make it shorter and more palatable. According to Reuters and the New York Times, there is a print of the film containing almost exactly the original German release of the film without editing. It sounds from the articles that the company that owns the distribution rights in the US has verified that the print is genuine, and I assume once restoration work is done they'll be releasing a version. Cool!

Labels: movies