Well, looks like they finally posted all right. I sincerely hope that this information is useful to those of you doing Unholy Things to your precious babies. I harbour no fear of operating on my own stuff, because I've never had much faith in warranties to start with, because the machines are old enough, that even a Total meltdown isn't the end of the world, and because I trust my own work more than some cold-pizza-scarfing gearhead's in the Repair Dept of the local mac store ( Victoria is a little out of the way, and we only have three mac retailers here ).
I would like to post information on building a car power adaptor, if anyone wants it. There are a couple of caveats on this subject, however: my old Powerbook 540c, which sadly turned up it's feet last year, ran on 19 Volts, and since a car only provides 11.8VDC to 13.5VDC, converting this to a HIGHER voltage requires some Black Voodoo, like a switching power supply. It can be done, but it's much more complex and hairy than stepping voltage down. If anyone wants to thumb through Radio Shack's power supply project manuals to see what I mean, they'll cringe at the Switching Power Supply section. However, for any PB using 12 Volts or less, it's very practical. The main issues are cleaning up the very 'dirty' power coming out of the car's electrical system (full of high-frequency transients and fluctuating voltages), and regulating the output at 3 Amps, which means you can't use an off-the-shelf 7800 series regulator IC. But, I figured it out, after some experimentation and smoking supplies, and finally came up with a solid design. I can run my PB 145 indefinately from the car, and even charge the internal battery while I work. Since this information would have to include circuit diagram GIFs, I won't be able to post it here, but am open to suggestions, should anyone want this info. Good luck to all the Brave Experimenters out there, I hope you'll let us all know how you made out! -- PowerBooks is sponsored by <http://lowendmac.com/> and... Small Dog Electronics http://www.smalldog.com | Enter To Win A | -- Canon PowerShot Digital Cameras start at $299 | Free iBook! | Support Low End Mac <http://lowendmac.com/lists/support.html> PowerBooks list info: <http://lowendmac.com/lists/powerbooks.shtml> Send list messages to: <mailto:[EMAIL PROTECTED]> To unsubscribe, email: <mailto:[EMAIL PROTECTED]> For digest mode, email: <mailto:[EMAIL PROTECTED]> Subscription questions: <mailto:[EMAIL PROTECTED]> Archive: <http://www.mail-archive.com/powerbooks%40mail.maclaunch.com/> Using a Macintosh? Get free email and more at Applelinks! <http://www.applelinks.com>
