Thursday, August 16, 2007

I've had a busy summer at work so I haven't been able to work on projects, but all of that is starting to slow down so I've started spending time in the shop again. The first order of business is to clean up the shop and do some improvements to it.

I've got a long list of improvments I want to do, everything from new table saw jigs, to exterior paint, adding a portable spray booth, etc. But the very first thing on the list is to get a better stereo setup so I can listen to tunes while I work.

Long ago when I was in high school I had a spare car stereo lying around and decided to turn it into a small bookshelf stereo for my room. I did it and it worked, but at some point I set it aside and forgot about it at my parents house for many years. When I went home for Christmas I spotted it up in a closet and decided to take it with me.

So a few weekends ago I decided to resurrect the stereo for use in the shop. The stereo was pretty impressive considering I built it in high school with almost no knowledge of electronics. I even built my own power supply for it (which is something I probably wouldn't even take on today). I took it apart and after cleaning up some loose connections I plugged it in and it actually worked! I still upgraded some of the components, such as before I had the speakers attached to the car stereo with some crappy spade connector, so I added some spring terminals for the speaker wires.

When I used to use the stereo it would sometimes cut out for a few seconds every now and then when it had been running for a while. At the time I didn't have the technical expertise to figure out what was wrong. But with my knowledge now I know that that sounds like a thermal issue. So I took a look at the power supply I built so long ago and sure enough the 7812 voltage regulator was burning hot. So I made the guess that it was overheating and the built-in thermal protection was kicking in cutting off the voltage output. I attached a heatsink to the 7812 and viola, I haven't had it cut out yet.

The only thing that didn't survive in the stereo is an old Sony FM modulator that I used to add an audio input (so I could tie in a CD player or mp3 player). It finally modulated it's last audio and it seems dead now, so I'm going to by an FM transmitter for my iPod and we'll be good to go.

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