> -----Original Message----- > From: Duo/2400 List > [mailto:[EMAIL PROTECTED]]On Behalf > Of Robert R. Daniel > Sent: Thursday, December 12, 2002 3:23 PM > To: Duo/2400 List > Subject: [Duo2400] ON Topic: Inverter Board > > > Just curious: what is the function of the inverter board in Duo > screen? I know that inverters convert DC to AC and/or vice versa. > Why is there an inverter in the screen? As I understand it, the > Duo power supply converts AC to DC for charging the battery and > running the motherboard. I presume the hard drive also runs > using DC electricity. Is the function of the inverter board in the > display to turn DC back into AC for the Cold Cathode Fluorescent > backlight bulb? If that's the case, how does one test for a bad > inverter board as opposed to a bad CCF?
The inverter board takes a DC input (12V?) and outputs a high voltage (90-150V AC) to power the backlight, if the bulb is failing then it will still glow, however it may be quite dim and often pink! However if the inverter has failed then the bulb will not light at all. I have found that the DC fuse on the inverter board quite often fails due to old age, however the switching transistors, the transformer, and the output capacitor are all common failure points. Please be careful testing the inverter board, although the current is quite low (a few ma) it can still be enough to give you quite a bolt, (powerbooks do not appreciate being convulsively flung across the room!!) also without a bulb to load it the output can rise to 400V or so. Ben. ---------- Duo/2400 List, The friendliest place on the Net! A listserv for users and fans of Mac subportables. FAQ at <http://www.themacintoshguy.com/lists/DuoListFAQ.shtml> Be sure to visit Mac2400! <http://www.sineware.com/mac2400> To unsubscribe, E-mail to: <[EMAIL PROTECTED]> To switch to the DIGEST mode, E-mail to <[EMAIL PROTECTED]> Need help from a real person? Try. <[EMAIL PROTECTED]> ---------- Dr. Bott | 10/100 Ethernet for your 2400 is finally here! MPC-100 | <http://www.drbott.com/prod/mpc100.html> RoadTools $30 PodiumPad available at Apple retail stores, $20 Traveler CoolPad at Staples. Both in white for iBooks at <http://roadtools.com> Midwest Mac Parts ][ <http://www.midwestmac.com> After-market parts for Macs. ][ 888-356-1104 ][ MacResQ Specials: LaCie SCSI CDR From $99! PowerBook 3400/200 Only $879! Norton AntiVirus 6 Only $19! We Stock PARTS! <http://www.macresq.com>
