7740 printer, new, repeated paper jams (in the back, paper easily removed) and also won't shut down. Pressing power button leaves it hanging with "shutting down" message but it doesn't actually shut down.
You can try to update the printer firmware ( OJ7740_1912A.exe ) to try to solve your issue
Also you can try use the next tool to diagnostic the problem
HP PRINT AND SCAN DOCTOR
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