can you use target disk mode with bad logic board

Try booting in option mode (hold down the option key while booting up) and target mode.do either of those modes work? If so, that's a good sign. With the hard drive missing, your goal is to get to a white screen with a folder and a blinking question mark. In fact, you shouldn't need a hard drive in the computer at all to do this level of testing - I'd remove it and all the rest of the extraneous peripherals (battery, extra RAM) until the computer starts behaving. It's not sounding like a hard drive problem. Thanks again for your help, reliable and wise iFixIt community. I feel like I've tried everything and haven't gotten very far. Other than that, I've wondered if disconnecting and reconnecting the PRAM battery could help get me anywhere. I'm thinking about attempting to boot from my MacBook Pro via target disk mode to avoid this issue, but I'm not sure how well that would work. What I'm wondering now, is if what I need to do is to completely erase the hard drive I'm booting with in order for the MacBook to boot up? Will this possibly solve the issue? I've tried booting from an install disc, but the optical drive won't read the disc and it ends up holding the disc hostage until I extract it by taking the drive apart. However, even with all the internals operating correctly, when powered on, the sleep light immediately lights up and remains lit and when resetting the PMU, no tone is heard after the sleep light flickers, which is unusual.

So, I'm convinced the display is working properly. I'm having the same issues as before, even with this second logic board, but I've noticed this time that the fan is working and the screen does indeed display that reassuring instantaneous white flash upon depressing the power button. For background on this undertaking, see the details outlined in my question regarding the first attempt. Tonight I made a second attempt to install a different logic board into a MacBook Core Duo that I've been working on.

Can you use target disk mode with bad logic board