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iMac G4 reactivation

Dmatt76

Dmatt76

macrumors newbie
Original poster
Feb 5, 2019
3
0
Poland
Hi
I got iMac G4 which I knew was mostly just a "shell" with quite a few parts missing - there's no RAM modules or disk drives. I finally got time to try to reactivate it and open it, so I have some question for a start:

1. What is this loose cable for and the port on the upper case (both marked red)
2. Can I safely connect it to power in this condition to check if the screen is working? Will it show any bios information, message about missing RAM, disk?

62e35611c66ec882med.jpg


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168ddc8275fb74b1med.jpg
 
Of assistance for anyone working on an iMac G4, the USB2 model Service Manual.

The 'loose' cable you note is the video connector, which only fits at one location on the logic board as shown on my photo HERE.
When fitted it is covered by a rubber boot also shown in the photo. You may have the boot missing which probably isn't a problem except when re-installing the logic board base assy to the upper housing, one must assure that the video connector doesn't become dislodged or you'll loose the signal.
The port on the upper case in your photo #2 is what I term the 'floating interface connector' and mates with a similar connector on the base assy. The 2 screws (which you shouldn't touch) which attach that connector ensure that the connector moves or 'floats', which is essential as when one is refitting the assembly it ensures that the male/female connectors mate correctly.
I assume all the other essential components are available (the IDE drives are easy to find, the inner PC-2700 184-pin SDRAM memory* less so). Don't forget to change the PRAM battery and repaste the heat-sink locations before reassembling the base assy.
*Note: The earlier G4 iMacs require a 168pin SDRAM memory at the inner location. MacTracker is your friend for identifying exact specs, memory requirements etc.

Fwiw, that rubber boot when placed over the connector is attached to the logic board with double-sided adhesive pad, and can be difficult to remove. I finally succeeded with a small craft knife.
 
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So the port on the upper case connects with the one IDE beneath it when you close the case?

I ordered a 144pin "easy access" RAM module, the inner is 168 pin according to this model data sheet - easy to find to. The worst part is the drive caddy which is only on eBay and the shipping costs twice or more the part :)
So my steps are:?
1. remove the heat pipe, clean, put new paste
2. PRAM battery
3. insert RAM
4. connect the video connector

and only then try to power it on?
 
Dmatt76 said:
So the port on the upper case connects with the one IDE beneath it when you close the case?

I ordered a 144pin "easy access" RAM module, the inner is 168 pin according to this model data sheet - easy to find to. The worst part is the drive caddy which is only on eBay and the shipping costs twice or more the part :)
So my steps are:?
1. remove the heat pipe, clean, put new paste
2. PRAM battery
3. insert RAM
4. connect the video connector
and only then try to power it on?
Click to expand...

From your description it appears you have one of the earlier 2002-2003 USB1 versions which requires 168pin (PC-133) RAM stick at inner location, and 144pin (PC-133 SO-DIMM) stick at outer location.
What is of concern is that you have no HD/OD drive carrier (is this what you term the caddy?) Anyone selling an iMac without the drive carrier is not playing fair as I'm sure they're very hard to find. (Having just checked even I don't have a spare) and I'm unsure if the caddy is common across the USB1 and USB2 models, even if its a common size across the 15, 17 and 20" versions - although I would bet it is.
Do you have the drive carrier mounting bolts? Without these you're stumped, as they're fairly unusual.
Can you link us to the 'drive caddy' you saw and the price? Depending on where you're located your best bet would be to find another cheap, exact model iMac as a source of spares - especially for an all important component such as the drive carrier. The last fully functional iMac I purchased was at a thrift store for the equivalent of $US15, and it was a 17" 1.25 GHz USB2 model.......
Assuming you have all the parts required, the assembly steps you list look correct, but you will of course need to reassemble the base to the main upper housing before powering on.
Good luck. Let us know how you progress.
 
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