C7769-60384 Drive Roller Encoder Sensor HP DesignJet 500 DesignJet 510 DesignJet 800 Plotter
 
New OEM Genuine HP C7769-60384 Replaces C7769-60172 Sensor, installed in the left end of the plotter, at the end of the main drive roller, to read the driver roller encoder disk.

This part is implicated as cause of system errors 53:10 and 56:13

Drive roller encoder sensor used in the following HP DesignJet plotter wide format printer models
DesignJet 500 (24-inch) C7769BR, C7769B
DesignJet 500 (42-inch) C7770BR, C7770B
DesignJet 500PS Series C7769CR, C7769C, C7770CR, C7770C
Designjet 510 24-in Printer  CH336A,  CH336AR 
Designjet 510 42-in Printer  CH337A,  CH337AR 
Designjet 510ps 24-in Printer  CJ996A,  CJ996AR 
Designjet 510ps 42-in Printer  CJ997A,  CJ997AR 
DesignJet 800 (24-inch) C7779BR, C7779B
DesignJet 800 (42-inch) C7780BR, C7780B, C7780CR, C7780C
DesignJet 800PS (24-inch) C7779CR, C7779C
DesignJet 815 MFP Q1279AR, Q1279A
DesignJet Copier CC800PS Q1262A
DesignJet Scanner 4200 Q1280AR, Q1280A

Refer to this article for troubleshooting "System Error 81:01, Media/Paper Jam" 
 
Refer to page 8-38 in the service manual for the remove and replace instructions.
 
roller encoder sensor hp designjet c7769-20093