Perhaps it's already known here on the forum, but yesterday I found this protoboard on eBay that appears to be from the Dual 500MHz upgrade for G4 Gigabit.
https://www.ebay.com/itm/1636297406...55-0&campid=5338722076&customid=&toolid=10050

It's a shame it can't be reconstructed without the schematics.
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https://www.ebay.com/itm/1636297406...55-0&campid=5338722076&customid=&toolid=10050

It's a shame it can't be reconstructed without the schematics.
.


