I had a B&W 17" Apple CRT display that had a failing flyback.
I bought a new flyback off eBay for about $20 and it took me about an afternoon to install it. Of course there are all of the normal electrocution warnings, but you need to be fairly proficient at soldering also. If you get the contact took you can melt the insulation on the wires in the flyback. The other issue is that you have to re-calibrate the display after replacing the flyback. I believe on the G3 AIO it can all be done from the front panel. Though I have repaired other monitors that require making adjustments inside of the monitor.
Given the vale of G3s I would suggest parting them out. I've never taken apart a G3 AIO but I would be surprised if there is less than 2-3 hours labor involved in the repair.
I bought a new flyback off eBay for about $20 and it took me about an afternoon to install it. Of course there are all of the normal electrocution warnings, but you need to be fairly proficient at soldering also. If you get the contact took you can melt the insulation on the wires in the flyback. The other issue is that you have to re-calibrate the display after replacing the flyback. I believe on the G3 AIO it can all be done from the front panel. Though I have repaired other monitors that require making adjustments inside of the monitor.
Given the vale of G3s I would suggest parting them out. I've never taken apart a G3 AIO but I would be surprised if there is less than 2-3 hours labor involved in the repair.