Denon DBT-1713UD Service Manual page 20

(7) Click Write(F2).
(8) When "Pass" changes to green, writing to the Flash ROM of the MAIN PCB is complete.
(9) Switch off the set unit power, and remove the 232C (TTL) side 4P PH connector of the USB - 232C (TTL) conversion
jig from the MAIN PCB (CON1).
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