PRAM battery change of iMac G3 DV400 SE

Hello

I need to change the PRAM battery of my iMac G3 DV400 SE as it hasn't been starting up for a few weeks now. I am posting here to get some safety advise, both to avoid electrocution myself and to avoid damaging the electronics. Please bear in mind I am a complete novice and a lay person. I have located the battery behind the RAM and Airport Card hatch - and I intend to change the battery through here rather than take apart the entire bottom half of the machine. Anyway, I have kept it unplugged for a few weeks. Now, do I need to get anti static gloves/ wrist strap, mat, etc? What tools do I need - for example tongs to pull out the battery or is it safe to just do it with bare hands? And how about clothing and shoe wear? Is a bed in a carpeted room OK? Or what sort of environment should I do this in? For that matter, should I do this myself or should it be handled by professionals?

Thank you.

Here is the Service Manual for that model G3 iMac. Anti-static wrist strap is the go and of course iMac not connected to mains power supply. I always did my G3 iMac on a bed, face down.


http://www.scribd.com/doc/103447/iMac-G3-Disassembly-Guide

Thank you Harry.

My pleasure Cappie. Everything go okay?

i'm waiting for a pair of anti static gloves (so I can use both hands) to arrive.
But to be honest, I am tempted to just 'do it' lol

Patience my lad, patience. Those old mercury driven tubes can hold a boot!

You really don't need any anti-static gloves to replace the PRAM battery in those iMacs.

You can do it through the RAM access cover with it removed of course and a long bladed screwdriver. Just flip the iMac over onto a soft towel and the memory cover at the top.

To make replacement and removal easier, I used one of those flexible push-button tong pickup devices you can usually get at a dollar store to grab the loosened battery, and place the new one on the top of the holding prongs and then push it into place with the screwdriver.

MAKE NOTE OF THE POLARITY AND DIRECTION BEFORE YOU REMOVE IT COMPLETELY. And keep the same polarity on the replacement battery.

EDIT:
PS: I'm sorry I completely missed you had already said you were going to use the "access door" method somehow. Good thinking and it works well. Just don't drop the battery when it's loose!!! And you're free from any high voltage if you restrict yourself to that area inside that iMac.

BTW: What shape is its hard drive which could be associated with the trouble you're having with it???

PPS: The flex tongs like these or similar:
http://www.ebay.com/itm/Magic-Hands...-Drain-Pipe-Cleaner-Picker-24-2-/351123129464

Thanks pm - I've just ordered similar tongs.

This is the exact battery that is currently installed:

http://ecx.images-amazon.com/images/I/21c48azg4WL.jpg

http://www.computer-answers.ca/wp-content/uploads/2011/07/PRAM_batteries_3-6_4-5V.jpg

So I've worked out the polarity from the picture also (the (green end) flat bottom (-) faces the hatch).
I'm feeling pretty confidant now that I can do it.

The iMac has been showing classic PRAM battery symptoms for a long time now - such as not booting up straight away after the power button is pressed - usually solved by a half hour or so rest. Also the screen goes black from time to time. The battery definitely needs changing in any case as I've had this machine 16 years since new and I just found out those batteries should be changed every three years or so ideally. So that must be a very good brand of battery lol.

The built in hard drive seems OK, I can dual boot between OS9 and OS 10.2. But most of the time I boot in to an external drive running OSX Tiger.

Aye, she's a sweet machine so it's better to be safe than sorry lol

Hello

This is an update. I have managed to change the PRAM battery - it wasn't difficult, just a bit fiddly. I tried using the flex tongs but found it rather difficult and the spring also sometimes just 'snaps' causing the battery to be ejected out at high speed. So I just did it with my fingers - wearing the static gloves ofcourse, which is actually not as hard as I thought but you need both hands. My apologies about one thing though (my memory is not what it used to be lol) - the battery that was already installed was this version:

http://www.usedmac.com/catalog/images/922-4028.jpg

And therefore the (+) end is the green end which is what faces towards the access hatch. .

Anyway, having changed the battery, I attempted to boot the machine. However, it still doesn't turn on. The power button turns green and then just dies - so I kept it plugged in for about a day and a half - however the result is the same. So my next attempt will be to reset the PMU.

Let's hope that the PMU and PRAM Resets fix the problem.

Have you tried all its boot source volumes and maybe its install boot disk…???

EDIT:
I can't recall completely, but I have a feeling that iMac has a PMU or Cuda Switch you may have to push, next to the memory under the access door I think.

Push ONCE ONLY for one second if I recall correctly on those iMacs, like most others with the switch.


EDIT 2:

Found this on the web, Spanish site, but English Service Source illustration just maybe help get things working…

Good news - as of around 20:00 hours GMT, the iMac has booted back to life.

There are still a few teething problems - it doesn't recognise the external firewire drive with Tiger loaded - it is currently running Jaguar and can also be booted in to OS9. Also it is not recognising the Airport card. But I hope these things will rectify themselves as the iMac has done so far.

Since I changed the PRAM battery the first time around, I only pressed the PRAM reset button later - then left it plugged in to the mains - and after about two months, it has come back to life. Oh - I also had to manually enter the correct date and time - it had gone back to 1970. Any way, will be grateful for any suggestions to rectify the remaining issues. Thanks again.

Heyyy "Captain Kirk"...back after 2 months fighting Klingons in the neutral zone!!! LOL

When you say that the iMac is not recognizing the external firewire drive…are you trying to boot from it? If so…have you pressed the Option key when rebooting? If everything is ok…you should get the choice to boot from either the iMac's internal drive with Jaguar…or the external drive with Tiger.

As far as the Airport card. Is the Airport cards antenna wire connected to the card? If so…could be a defective Airport card (it happens).

- Nick

Well I guess it's partially rejuvenated which is quite amazing in itself. Well done.

Any other ports or USB to try on the external drive…???, and maybe try another cable, and that iMac can only go to Tiger Maximum MacOS: X 10.4.11, and are you sure there's even an Airport card installed. They were an option I believe. But a recent USB wireless dongle would probably be a better option these days — if the old OS will support it.

More info at:
http://www.everymac.com/systems/apple/imac/specs/imac_se_dv_400.html



- Patrick
======

That date and time to 1970 is always the sign the PRAM battery needs replacing.

Regarding the external drive, I trust you are not trying to boot from it? With USB1, the first iMac with USB2 was the 1GHz model a year or two later, booting will probably not be possible. FW400 should work if the external drive caddy is FW400 capable.

Update - I have solved the Firewire problem by turning off the power of both the iMac and the external Firewire Hard Drive, then unplugging both from the mains for ten minutes - after which I plugged both back in to the mains and powered up both units. This did the trick. I can boot back in to Tiger again. Tomorrow I will sort out the Airport card - I think it just needs to be reattached more firmly. Thanks again.

More good news - I have solved the Airport card issue. As per my research of the internet - I just reattached the Airport card more firmly - it actually clicks on each end when it is properly attached. So now the iMac G3 400 DV SE is back to full health. I am going to consider whether it is worth investing in additional RAM to take it up to a Gig (it's got about 640MBs at the moment) - or should I sell it while there is time lol (although parting will be so hard, I've had this from new for 16 years - not to mention it is not worth a lot in the real world - but is the space worth it today?). Web surfing with TenFourFox is very clunky (forget Youtube lol) but I love having iTunes 9.1 streaming Radio again - as well as playing my own stuff. Any way, thanks for everyones input and I hope this info helps anyone else that suddenly finds their G3 iMac not powering up - DO NOT CANIBALISE or dispose of in any way - these things are still gems.

Congrats, and yes the proper connections for those Airport cards can be brutal, almost to to point one thinks something may break to get them to click in fully.

It's nice to hear you can still get some use out of it as you say, it's not worth much in the real world.

My old LC 630 and G3 DT and G4 1.25GHz MDD Macs still get some occasional use in their allotted basement area, but getting less and less I must admit.

Thanks PM - there's tonnes of the software for these old machines but it's more practical to use newer more efficient machines with better apps.
Which is why I'm just wondering if it's worth maxing out the RAM for the G3 iMac.

You'll need to double check your model for the correct RAM as there are differences as shown by our local and very reputable dealer:
http://www.canadaram.com/apple_imac_g3.htm