On Apr 25, 2009, at 4:49 AM, Ernest L. Gunerius wrote: > > Hi Bill; > > Do not feel abashed, there are many mysteries in Switch Mode power > supplies. They gave me many 100 hour work weeks, intense headaches, > sleepless nights and good pay for 20 years. > > The advent of Wall Worts and Bench Bricks came about so that > Equipment designers no longer had to fret and stew over International > Regulations involving Safety Qualifications with attendant costs and > Liabilities associated with the Switch Mode Power Supplies. > > The Green Wire(line grounding pin) is usually tied to > Equipment(Chassis) ground. Circuit DC ground is tied usually at one > spot to equipment ground. That takes care of Static potentials. > > Secondary(low voltage) Isolation is by the High Frequency > Transformer. This is the expensive Componant to design since it must > with hold a quite high DC voltage (at least during qualifying tests) > with thick insulation while maintaining tight coupling. > > To each his own, > > ErnieG
So I'm guessing there's really no discharge method for a capacitor in a psu? Maybe that's what the original poster also wants. I'm sure the others as well as me, appreciate your expertise. I have an HP type psu that could use a fan (or 2 as I have learned with this thread) replaced, but we chose to buy a whole ps-unit and replaced that in his HP awhile ago ... mainly because of the uncertainty and danger of electric shock. My main concern is whether something like this can be solved for a professional amateur like myself (someone who successfully replaced a QS 2002 Dual 1GHz mobo, PCI cards, AGP video cards, completely disassembled/reassembled a Yikes! for cleaning, etc), and maybe others listening as well, over a forum discussion like this ... sort of borders on "Don't Try This at Home" kind of thing. I never disassembled the psu. Maybe overkill on the warnings (borderline pun intended). Bill Connelly artsite: http://mysite.verizon.net/moonstoneartstudio myspace: http://www.myspace.com/moonstoneartstudio --~--~---------~--~----~------------~-------~--~----~ You received this message because you are subscribed Low End Mac's G3-5 List, a group for those using G3, G4, and G5 desktop Macs - with a particular focus on Power Macs. The list FAQ is at http://lowendmac.com/lists/g-list.shtml and our netiquette guide is at http://www.lowendmac.com/lists/netiquette.shtml To post to this group, send email to [email protected] To unsubscribe from this group, send email to [email protected] For more options, visit this group at http://groups.google.com/group/g3-5-list?hl=en Low End Mac RSS feed at feed://lowendmac.com/feed.xml -~----------~----~----~----~------~----~------~--~---
