Power Up Basics (PC Engine Duo-R)
The PC Engine Duo-R has a DC 9V (4.8mm x 1.7mm) center positive power supply.
To power from the bench simply solder wires to the ports rear pins and apply 9V.
The expected power draw when turned on without the CD drive spinning is around 500mA. When the disc spins it goes up to 700mA.
Usually a well tuned disc only pulls 700mA, and one that is struggling to read/seek pulls up to 1.2A.
A successful boot with no HuCard and no disc should yield the Super CD-ROM² splash screen, with Push Run Button! flashing.
If you get a white screen and a HuCard is inserted, it is a failed load of the card. If there is no card inserted, the console thinks there is, so clean the port with IPA.
It can also be an indication of a fault on one of the HU ASIC chips or damaged traces, causing it to fail to boot into the BIOS.
This usually indicates a faulty 6280 or 6270 IC. It can also be traces to them are damaged, or shorts.
If you get this message after inserting a disc and pressing Run then the disc spins and stops with the message Please Set Disc it is a failed disc read so try tuning the laser.