Upgrade iMac G3 via logic board swap?

[Jiggly Billy]

We may be picking up an iMac G3 400mhz DV model here soon, but I was wondering if you could swap in the later 500-700mhz model logic boards as a way to upgrade both the CPU & GPU at the same time. Would this work?

Thank you all!

 

[philgxxd]

I tried a Summer 2000 500MHz motherboard from an iMac G3 Graphite and it were a simple swap for my 1999 400MHz iMac G3 DV. At least a 500MHz board from this moment in time will be possible to swap.

I'm currently trying to repair a last model 700MHz and i noticed that the heatsink were different in shape and located slightly in another spot.

I think you could move the older heatsink
but a safer bet would be to have the divider panel of these newer iMacs. - I have to look again but i think the older heatsink is screwed while on the newer models it's fixed because it's part of the extruded metal divider panel-

Here are some photos of the divider panel from the 700MHz model. I will try to add some of the other one ASAP.

1. Upperside (where the CRT and PAV board sits)


2. Underside (where the Logic board sits)
There you have the heatsink with a thermalpad on it (i think it's 1mm thick)


3. Close-up of the heatsink

 

[zackkmac]

I have a graphite G3 400MHz (DV) and I swapped a 700MHz board into it several years ago from a snow model.

In my case I don't recall there being any difficulties or the need to swap the divider/heatsink panel. In fact all I bought was the board itself.

 

[philgxxd]

Interesting.
Will have a look probably tomorrow and confirm if the heatsink is in another spot or not.

 

[philgxxd]

1. Divider panel from iMac G3 500MHz Snow year 2000


2. Divider panel from iMac G3 700MHz Snow
year 2001


There are quite different so be aware.
Maybe it depends on where it was made also as there were made in US, europe and Asia.