Designjet 500 Error 87:13

"I have an HP Designjet 500ps. I have recently changed the carriage belt using your video but I am getting "Error 87:13 - Possiblty Paper Jam com up" I have followed the instructions on the screen a number of times but can not seem to get past this point. Would you have any suggestions?"

The plotter is not able to detect the lines on the encoder strip.  The encoder strip may be installed incorrectly, or there may be an obstruction of the encoder sensor on the carriage.

The first thing to check is to see if there is any deflection in the encoder strip when the carriage moves, especially at the extreme right side.  Remove the right end cover and rotate the white plastic gears on the service station until the carriage is free to move.  Observe the encoder strip from above while moving the carriage.  If any deflection is seen, the encoder strip bracket on the right end of the plotter is out of position.  There is a hole in the bracket that needs to over a stub in the black plastic frame.  You may have to use a little force to move it forward to click over the stub.

The other possibility is that the encoder sensor is obscured by paper dust or ink overspray. Try using compressed air or canned air to blow out the encoder sensor.

One of these should solve your problem.