Daniel Rex <[EMAIL PROTECTED]> on Wed, 19 Jan 2005 09:24:21 +1100 wrote: > Hi Pat; > > Funny you should ask . Last week someone stumbled on my website by chance > and emailed me about that (this was before I joined this group, suggested > to me by an eBay buyer). > > PRAM (parameter RAM) stores things like date and time on a Mac, and the > mobo has a battery or cell to save them when the computer is unplugged > (just like a PC and its BIOS settings). > > Yes, as you know, most Macs (from Classic, LC II, III, 475 to G5) use a > 3.6V Lithium ion half-AA size cell. These are still freely available from > electronics stores (such as Jaycar online), so I can get them ok, for $6 to > $9 each, though you might find a better deal shopping around or buying in > bulk. I don't try to make these, but maybe a battery holder, 3x1.2V NiMH > cells and attachments (like alligator clips) to the mobo connector > terminals might do fine. > > However, I'm talking about the 4.5V rectangular block "battery" consists > of 3 x 1.5V cells, and is really like a half-9V transistor battery. When I > found out how rare these are ($15US or more to order), I decided to try > something homemade, though I'm not good with electronics or soldering. > There are a select range of 040 to G2 (mainly the all-in-one models [LC > 575, 580, Performa 5000 series] but also the 4400-7220 (which plays "dead" > when the pram battery is flat), LC 630 and others) Macs which use this > battery. > > My first approach was to dissect a 9V transistor battery and see if I could > "re-pack" an existing 4.5V battery with 3 cells from one of those..... too > messy, I decided. Then I went for the option of carefully soldering 3 x AA > or AAA cells in series, and soldering the connecting wires from the Mac > battery (just snip them off an old battery) on, red to the +ve, black to > the -ve. If you wrap the three AAs together with good tape, then use the > sticky velcro off the old battery too, it will sit in place on the > motherboard ok. Have done this with about 10 Macs now, and if you use good > alkaline AAs, it will last 1-2 years. > > I have been cautioned about taking too long to solder the wires onto the AA > terminals, as it can heat up the battery a fair bit. So far, I've had no > problems, but light abrassion of the ends of the AA cell can help the > solder "take" better. Short bits of tinned copper wire work well, but > insulated copper wire is ok. I could send you a photo of a finished product > later. The battery-holder option for this might be better, I should try it, > that would eliminate the need to solder onto the AA cells themselves, you'd > only need to solder the + and - wires to the battery holder, and it would > be reusable. I'll look out for a 3xAA battery holder on Jaycar etc. > > I'm just trial and erroring with this, and am no electronics expert, so > some advice and suggestions would be appreciated. > > cheers, > -Daniel > > > > >Hi Daniel, > >"Home-made" PRAM battery? > >vas ist das? > >Regards, > >PatC. > >
Did the same thing at school to extend the life of 25 5260's (why? you may well ask). Dick Smith had 3 AA battery holders for around $1.80 (with connecting wire fitted). Fitted 3 AA batteries for approx $1. Cut the connecting wire from the original battery, soldered to the new wires and tossed back in with double sided tape to a spare space on the logic board. Total cost (excluding my time ~ 10 mins) about $3 which was a heck of a lot better than the $43 I got quoted for a proper battery replacement. I think that you just have to check the batteries now and then, perhaps replacing every year, as normal AA cells can be a bit prone to leaking as they age and this stuff would not be kind to Logic boards or much else. --- Cheers Greg =:)([EMAIL PROTECTED]) "Anyone know how to set a laser printer to vaporise?" -- Outback Mac is sponsored by <http://lowendmac.com/> and... 123Inkjets.com <http://lowendmac.com/ad/123inkjets.html> Support Low End Mac <http://lowendmac.com/lists/support.html> Outback Mac list info: <http://lowendmac.com/lists/obmac.shtml> --> AOL users, remove "mailto:"; 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/outback.mac%40mail.maclaunch.com/> iPod Accessories for Less at 1-800-iPOD.COM Fast Delivery, Low Price, Good Deal www.1800ipod.com
