Our Stratasys F170 has stopped printing support material. In its place, it prints normal filament. I'm looking for ideas why this might be and things to try to diagnose and fix it [I'd never seen a 3D printer until someone asked me to help fix this, so be kind and clear - I may be using the wrong terminology].

I guessed it could be a configuration/setting, bad software (or firmware) or bad hardware, but:
- configuration/setting: the users assure me you can't tell the printer to print the wrong material (normal filament in place of support material). Is this true?
- software: I upgraded grabCad to the latest version and the problem persisted.
- firmware: I upgraded the printer's firmware to the latest version and the problem persisted
- hardware: I'm now guessing this is where the problem is ... failed component on a circuit board that chooses which material/head to feed?

If it helps at all, after the firmware upgrade a test print ran after which I can no longer unload the support material. I can click the unload button but nothing mechanical happens. After a few clicks and some waiting the printer says the support material is unloaded ... but it's still locked in.

Sounds to me like a problematic circuit board ... can you just buy new ones? Any help or tips appreciated.