01-01-2012, 03:09 PM

I have always fancied a 'go' with a mac - are they really better than windoze boxes ? Are they really free of viruses or the dreaded blue screen of death ?

Well, I am about to find out.

First, a bit about me and what I have got now (I will not list my old laptops or MS boxes) - I have bought a broken iMac G5 17". It cost me £12 plus a trip to Leicester (about 40 miles) to collect the beastie. I have spent the past 50 years 'doing' electronics so can sort most things but am stumped here.

Story from seller - it's been sat in my spare room for a couple of years, got off my brother. I have turned it on and got the 'chimes' but nothing else. It has a password which you will have to remove but is all complete.

Reality - no chimes on switch on. Opened up and found domed caps everywhere (I counted 11 of them) so I got a kit off fleabay and changed them all. What a job, even with a Weller iron and a 900 deg F tip.

Anyway, it fired up and got me to the login screen. So I turned it off and went on the www to consult the oracle (here) re password changing or removal or whatever. Got back with printouts and the **?!* thing would not run properly - sometimes no chime, sometimes got to apple logo, sometimes just stuck somewhere and appeared to do nothing.

System is really old G5 - serial starts off W84510xxxx which seems to say it was built in China in week 51 2004. I have looked in the power supply (after I had modified a flat screwdriver with a centre slot to undo the 'tamperproof philips' screws and all seems OK, no caps appear duff.

The last few times I tried powering it up I noticed that when the apple logo appeared (if it got that far) the power on light showing at the front went out and a short time after the cpu fan wound itself up to overdrive setting.

I now suspect the power supply (614-0329 by Delta) has problems and am looking for confirmation of this, or any other suggestions, to get this system up and running again.

I believe the logic board is now OK, seeing as it did boot up to the login screen after I changed the caps even telling me it was running OS - X, though I did not notice what version (suspect 10.4 Tiger).

SO, over to you lot and we shall see what we can manage between us all.

01-01-2012, 08:45 PM

Sounds like an interesting project to keep you busy for awhile. Go to the iFixit: The free repair manual site and have a look at their tear down and take apart instructions. They also have some excellent trouble shooting tips for most Apple computers even some of the vintage models like yours.

The site is located in the US but you can always round up the parts in the UK if you have to. Another good site for older computers and parts is
Mac Repair - Mac Parts and Service for Apple Macbook, iPhone, iPad.

Good luck with the repairs. Some of the guys here are expert with older machines so hang around and wait for some more replies.

01-01-2012, 09:15 PM

The Logic Boards sounds intact because it was able to boot after you replaced the caps. The Power Supply to me also sounds like a likely culprit, as that can be known to cause the issues that you're currently experiencing.

In my opinion I'd say try to pick up a power supply and see if that does the trick. Only trial and error is the real effective method with a problem like this.

01-03-2012, 06:38 AM

Well I fired up the iMac this morning and it actually worked again, for a while (about 4 minutes). It got to the login screen and I clicked the 'old' username and it gave me the desktop. Obviously no password for user.

However, the power light had gone out partway through bootup, about when the apple logo appeared - is it supposed to do that ?

Just after I had access to the desktop it locked up - could not use the mouse or keyboard so I had to power down. Then it would not start up again. Ho Hum, such is life ...

So I took the power supply out, I am getting better at dismantling the iMac - about 5 minutes to get it ALL in bits, MB out, the lot. Anyway, I dismantled the power supply - had to make a notched flat screwdriver to undo the 'philips + pins' to remove the top cover. Who thought up the terrible arrangement of the cable lock fitting being part of the mains input bracket ? I can see that refitting the bracket to the cover wil be "fun".

What a doozy !! The power supply innards are not one of the 'usual' ones, not the 'A', nor 'B','C','DD' or 'EE' - so now what ? Caps all look OK to me.

The supply also has a daughter card at the one end - what is all that about ?

Pictures attached. Comments / suggestions welcomed.