New Power Cord Stopped Working

DO NOT use the HP power adapter that is 19V / 3.95A. That is too much power for the Scanjet, which is expecting 12V DC (and a much lower amperage). It's possible that hooking up this power adapter may further damage the electronics inside the scanner. If the second adapter has stopped working then it is possible that the internal circuit board has damage already and another adapter may not work. If you have access to a multimeter / voltmeter you could check for the 12V coming from the adapter. If you're getting the 12V, then the internal circuit board to the Scanjet is probably defective.