If you are looking for an upgrade or replacement logic board, the actual part number is C7776-60151. • Component: HP GL/2 Accessory Card / Formatter Board (typically includes a 128MB memory module). • Compatible Models: Designed specifically for the HP DesignJet 500 and 500 Plus series. • Where to buy / view specifications: You can find replacements on listing sites such as AliExpress or refurbished options via CDS Printer Solutions.