After working well for ten or fifteen years, the rubber friction rollers that drive the paper through the printer deteriorate. We cannot replace the rollers, and we can’t buy replacement mechanisms from Epson. If your Model 35P no longer advances the paper, the only fix is a print mechanism transplant. To support our customers, we’ve purchased printing calculators at retail. We salvage the print mechanisms, install a connector on the signal cable, and check it for proper operation. You can replace the failed mechanisms in your Model 35P in a few minutes. Directions with pictures are provided. If you have problems, then you can send the system back to us and we will make it whole. The newer mechanisms print slower than the original units, but they use less energy from the battery. Some of the printed characters are changed; you might see $ instead of S for standard deviation, but
the velocity numbers are correct.
P.S. The replacement does not include the plastic housing that holds the mechanism.
You can’t simply buy the replacement mechanism and add a printer to a chronograph that did not originally come with a printer.