7470a plotter gummy wheel question


The 7470a plotter has two wedge-shaped gummy wheels located over the two abrasive wheels which move the paper back and forth. One of my gummy wheels has developed a flat spot in it. This causes quite a bit of chatter when the paper is being moved back and forth.

Has anyone here repaired one of these before? Is the wedge shape critical or will a straight cylinder work?



The paper drive wheels in the HP97, etc also develop flat spots. A little careful work with some sandpaper can work wonders in getting them going again.


From an article I believe I read in HP Digest a long time ago, the tapered roller shape is designed to keep the paper taught and against the guide at one side.

So, I would attempt to maintain/reproduce the shape as much as possible, although the overall diameter may not be critical.

If the flat spot is a result of leaving the roller pressure engaged for a long time, perhaps it will improve a bit after some relaxation and use.

If you find/develop a good replacement, please let us know.

Good luck!

Possibly Related Threads...
Thread Author Replies Views Last Post
  HP 7475 plotter available Dave Shaffer (Arizona) 0 353 08-26-2013, 06:18 PM
Last Post: Dave Shaffer (Arizona)
  Service manual for HP9872C plotter? John Ioannidis 2 555 05-21-2013, 02:06 PM
Last Post: Juergen Keller
  [Function] Google Plotter robertoataulfo 2 616 02-14-2012, 01:59 AM
Last Post: Lyuka
  Gummy wheels for 41 series card readers William L. Drylie 5 722 08-30-2011, 11:26 AM
Last Post: William L. Drylie
  HP7470A plotter with the HP-IL interface Richard L. Taylor 2 528 08-03-2011, 03:20 AM
Last Post: Juergen Keller
  HP7470A Plotter calibration with an HP-IL interface Richard L. Taylor 3 575 06-23-2011, 10:30 PM
Last Post: Garth Wilson
  Running an HP7475A plotter on the HP-IL Loop Richard L. Taylor 3 586 01-14-2011, 02:48 PM
Last Post: Richard L. Taylor
  Rarity and Value of the 82184A Plotter Module DavidShenk 3 587 09-01-2010, 01:42 PM
Last Post: DavidShenk
  7470A Plotter Programming Examples DavidShenk 2 522 06-04-2010, 11:10 AM
Last Post: DavidShenk
  Shirt pocket plotter for HP41 Wilhelm Taylor 3 541 03-15-2010, 11:44 AM
Last Post: Steve Leibson

Forum Jump: