I always hated trying to identify the later iBook G3 Dual USB models - it becomes a mess IMHO.
In System Profiler, check to see what graphics card it reports. Also, check the model identifier is PowerBook4,3 and that it is 800Mhz G3 CPU.
Other than a unique failure of the solder on the GPU, which I'm not confident this is, you could try an NVRAM reset from within OpenFirmware.
From a completely powered off state, power on the machine and quickly hold down the "Command" , "Option", "O" (the letter O) and "F" keys until you come to a text prompt.
Next type (without spaces):
reset-nvram
and press return
then type:
set-defaults
and press return
then finally type:
reset-all
and press return
A couple of lines of text will flash up with that last command, and the machine will reboot. If this solves the problem, it's likely that a Dual Monitor Open Firmware hack was applied at some point. The iBook never officially supported 'dual' displays, but rather simply 'display mirroring'. The iBooks with the ATI Mobility Radeon 7500 are actually capable of true 'dual displays', but Apple crippled them in OpenFirmware.
If that doesn't fix it, then all I can suggest is that the ATI driver is too old which may mean the MacOS 9.2.2 you have is not the correct version for that motherboard - I've seen this myself. Oddly, some iBook G3 late Dual USB models would have their logic board replaced under a repair extension program, and the GPU was a MUCH later type than the software it shipped with. Under those conditions, Apple supplied a free upgrade to MacOS X 10.3.2 and an updated set of ATI drivers for MacOS 9.2.2 - without them, the display is about 1/4 the size in the middle of the screen, surrounded by black. But IIRC the upgraded motherboard was only the 16MB VRAM models.
So... take your pick. That's about all I know.
