I've never installed an SSD to a G3 iMac but have done to a G4 iMac.
I believe I used a StarTech IDE 40pin PATA to Sata 2.5 adapter which cost about 20 euros (US$ 22) the quality of which was good. You can find much cheaper, but the soldering quality is not top rate and lots of flux residue is left behind on the board; I tried one after thorough cleaning the board with isopropyl alcohol and it functioned ok with a Sandisk SSD.
HERE's the cheapo version, and the more expensive Startech adapter.
I've never installed an SSD to a G3 iMac but have done to a G4 iMac.
I believe I used a StarTech IDE 40pin PATA to Sata 2.5 adapter which cost about 20 euros (US$ 22) the quality of which was good. You can find much cheaper, but the soldering quality is not top rate and lots of flux residue is left behind on the board; I tried one after thorough cleaning the board with isopropyl alcohol and it functioned ok with a Sandisk SSD.
HERE's the cheapo version, and the more expensive Startech adapter.
But as mentioned earlier, mine was ok after a meticulous clean-up, and the absence of jumpers was not a hindrance.
It was in an iMac G4.Did you use it for an iMacG3 or G4? I do ask this, since I have two spare adapters with 4 pin-jumpers (= 2 positions) that didn't work on the G3 but might use them with an iMacG4.
(BTW, writing this, I become aware now, that I didn't check the "no jumper-set" option on that specific 2-jumper/4pin-model ....)