HP 97 latest PCB with blown capacitor : Alive !

[[kby]]

(12-13-2020 08:34 PM)Chr Yoko Wrote:  [quote='AndiGer' pid='140090' dateline='1607704433']

- The Printer is very slow/sluggish to move paper and lines overlaping : maybe i need to check its mechanical parts/wheels.

The plastic wheels on the feed roller are probably glazed. There have been articles posted elsewhere on this forum, although I ended up using the same square o-rings I like for card reader rebuilds, which it sounds like you also use. I did have to file those down a bit; did those by putting the axle pin of the roller in a Dremel chuck to spin it then held a small flat file to allow it to sand it down. Unfortunately it doesn’t work so well on both ends; too much play so end furthest from the chuck has too much wobble. It would be nice to do both sides at once since they have to be the same diameter. The actual diameter isn’t that important but if they are not the same the paper could track crooked. It didn’t seem too hard to get it to work though. You can test for being level by rolling the roller down a flat slight slope and observing that it doesn’t veer to one side or the other; that seems good enough. Make sure you remember the orientation (left right) of the roller when you take it out. It us ratcheted to roll in one direction internally so won’t work if inserted the wrong way. There are some gaps in the plastic that surrounds the central metal axle; you want the smaller gap on your right as you face the calculator (the “home” position of the calculator is to the right as you face the front of the calculator with the printer on the right hand side and keyboard facing you.