How do you fix an Apple Hardware Test (AHT) configuration?
For Apple Hardware Test to work, you need to ensure you're using the correct version for the model of Mac you're testing.

Assuming you have the model identifiers correct:


the MacBookPro6,1 is a Mid 2010 17" MacBook Pro which uses AHT 3A175
the MacBookPro8,3 is a Early 2011 17" MacBook Pro which used AHT 3A211


My guess is that you're trying to run the same version of Apple Hardware Test (AHT) on both machines, and this is where you're running into problems.

[UPDATE]

Below are direct links to download each of the above versions of AHT directly from Apple:


AHT 3A175 
AHT 3A211


You can run AHT from a bootable USB drive, but first you will need to copy the AHT onto your USB drive and bless it so it can boot your MBP.