if your roll chart binds at the top and bottom so that some of the tube data cannot be accessed, try this as a remedy.

remove the chart and chart frame from the tester, carefully remove the chart rolls from the frame.

roll the charts together in your hand untill the part number and print date are visible between them. this should be right after the word STOP appears.

place the rolls in back in the frame with the gears engaged and the part number visible in the window.

reinstall the roll chart and chart frame into the tester.

there will be a good deal of slack in the rolls when they reach the middle area of the chart and this can cause some binding at this point but it is the only way to install the rolls so that each end can be viewed

hope that helps.

While you are at it, check that the ends of the paper roll chart are still taped to the wood roller. If the tape lets loose, the unsecured end of the paper roll chart also causes problems. That was the problem with my Hickok 600A

On rollers that tend to swell and bind with seasonal humidity changes where you cannot roll it to the end sometimes..I also add six inches to a foot of extra "leader paper" to each end of the roll, which helps take up the seasonal changes, allowing rolling it to the end. Also, if you place repair tape to one side of a paper roll, be sure to also place the same length and thickness of tape to the other side (left or right) of the roll at the same place, so the roll will continue to roll up evenly and not tend to bind. Make sure there's always some airgap between each paper edge and the left & right roller flanges. Some of these are the same "tricks" used with player piano rolls.