Date: Sat, 03 Nov 2001 08:37:27 +0800 From: Raymond <[EMAIL PROTECTED]> Subject: 'PowerXtender' power adapter verdict
Hi all! Well I've just woken up and the first thing I did was open up that power adapter thingy (ref an email or 3 back regarding the PowerXtender adapter which can boost an input of 10-16 volts to an output of 5-24 volts for powering a laptop from an aircraft EmPower jack or an automobile ciglighter jack) ... looks like they're not trying to make things easy for whoever wants to reverse engineer it and rig it up differently ... inside appears to be 4 regulators or transistors (TO-220 type cases), a switchmode regulator, a couple of beefy inductors and a few caps plus a pile and a half of surface mount thingys. No useful markings whatsoever ... *sigh* perhaps I should have taken the hint when I opened the outer plastic case to find the PCB completely surrounded by a copper shield that was SOLDERED on ... still I spent half an hour with my underpowered soldering iron trying to remove it ... hehe Looks like the extension lead (which is unique for each brand/model of laptop) in fact has some smarts in it that tell the power adapter how many volts to pump out (and it also turns out the thing only seems to supply a single output voltage at a time). Certainly I don't think the plug is a passive device and I can't open it because its all molded together. The power adapter is also smart enough to figure out when the extension lead is plugged in and won't supply anything otherwise (apart from what appears to be a very well regulated precisely 1 volt output and a reasonably high impedance 12 volt output - having my multimeter on too high a range even caused it to drop to 11.5 volts). Of course, all this wouldn't be a problem if the DEC HiNote used 15 volts but unfortunately they use 24 volts which I'm quite sure has a damn good chance of frying the Libby's electronics ... *sigh* well at least I can just shove a linear regulator in the circuit and hope that the libby won't draw more than 1 amp ... it could be worse, like the HiNote only needing 12 volts in which case I'd be stuffed ... hehe ... I wonder what the chances are I can make the regulator circuit into a suitably well concealed blob such that the whole lot won't look like some detonator or something if I use it on the plane next time I fly ... I dunno how appreciative the hostesses would be, especially in this current climate, if they see someone with a mass of obviously home-made wires and whatnot plugged into the aircraft supply! ;-) So now I've got to figure out how to solder this thing back together again (the biggest problem being I've only got a 25W soldering iron so within about 2 seconds of touching the metal shield, its sucked away so much heat that the iron almost gets attached to it) ... wish me luck! Oh ya, and if anyone is wondering, no I've got NO idea why I wrote this email but seeing as I've already written it before I wondered this I figured I might as well send it and therefore not have wasted the effort ... *sigh* the joys of waking up with a brainwave ... :-) - Raymond --- /~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~\ | | "Does fuzzy logic tickle?" | | ___ | "My HDD has no reverse. How do I backup?" | | /__/ +-------------------------------------------| | / \ a y b o t | [EMAIL PROTECTED] | | | HTTP://www.raybot.net | | ICQ: 31756092 | Need help? Visit #Windows98 on DALNet! | \~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~/ ************************************************************** http://libretto.basiclink.com - Libretto mailing list http://libretto.basiclink.com/archive - Archives http://www.picante.com/~gtaylor/portable/faq.html - FAQ -------TO UNSUBSCRIBE------- Reply to any of the list messages. The reply mail should be addressed to: [EMAIL PROTECTED] - Then replace any text on the message's subject line: cmd:unsubscribe --------TO UNSUBSCRIBE DIGEST------ Do above but with this on subject line: cmd:unsubscribe digest **************************************************************
