Replacing A Hermes 3000 Platen

     Those of you lucky enough to own a Hermes 3000 probably already know that the platen on a 3000 is one of the hardest known substances on the planet. It's more petrified rock than rubber roller. Maybe you have even thought of replacing the platen but it looked like a complicated procedure. In fact, it can be, but if you follow this lesson you will see that it's easier than you thought. The only tool you will need is a flat head screwdriver with a skinny blade. Your first tip if you can, is to magnetize the screwdriver. Rub the tip of the screwdriver on a magnet. This is a huge help for putting the set screws back in place. The screwdriver also acts as a screw starter.
     Let's start. Move the margins out to the ends of the carriage. Disable the index mechanism by moving the linespace lever to to dot mark above the one linespace. The platen should spin freely without clicking. Next, remove the left platen knob by removing the screw with locking washer and the platen knob will pull off the shaft. Carefully set aside. Next, grab hold of the hub that the knob was on and slowly twist and pull out only about 3/4 of an inch. This is crucial. Only 3/4 of an inch no more. If you pull the hub completely out, you are in trouble.

     Now, gently push the carriage across the machine to the left margin. Next we will remove to two set screws that hold the shaft to the platen. The right platen knob stays attached to the shaft because that's how we pull the shaft out of the machine. These two set screws are located on the right end of the platen on the collar (just inside the frame of the right carriage end). They are small so take care not to lose them. Magnetizing the screwdriver will assure this.



removing the two set screws from right side of platen

      Now we can remove the platen shaft. Grab the right platen knob and gently twist and pull until the entire shaft comes out of the machine. So far, so good.



pulling the right platen knob removes the shaft

      Now we can lift the platen out of the machine. Hold the hub sticking out of the left end of the carriage firmly and then lift up the right end of the platen. Slowly twist the platen and slide out to the right. Alright, we're half way there.



hold left hub firmly, lift up platen , twist and pull to right

       Take a good look at the index assembly on the left side of the carriage. You can see why I stressed not pulling the hub assembly all the way out of the machine. Then the actual index rachet assembly would fall apart and you would be in trouble.




close up shot of the hub assembly for the index assembly

      I wanted to spend a minute on this hub assembly that holds the index rachet in place and that the left platen knob attaches to. This part is really the only potentially troublesome part of the whole process. This part also acts as a index detente release. That's what the two pins that fit into the hub are for. You need to study how the two pins fit into the hub because when we slide the platen shaft back into the platen, it's easy to knock one of these pins out of place.
     OK, time to put in your new platen. Just do everything in reverse. First, hold the hub assembly on left firmly, slide left end of platen onto hub and index assembly and gently twist platen till it is in place and push right end of platen down into place.
    

slide new platen into place

     Next you will put the platen shaft back into the machine. Notice the left side of platen shaft has a flat spot on the shaft. Keep in mind that the left platen knob will screw into the flat spot on the shaft here. Pick up platen shaft by right knob and insert into right side of platen, gently twisting and pushing. Stop half way in and then grab hold of left hub assembly firmly then continue to push shaft into machine, twisting and pushing until it comes out left side and right platen knob is firmly against machine.
     Next, you can reinstall the two set screws in the right collar of platen. For the final part, move the carriage all to way over to the right margin. Now you can reinstall the left platen knob. Hold the hub assembly, you might have to push it into the machine a bit, and turn the right platen knob so the flat spot on the shaft lines up with the screw hole on the left platen knob. Push the left platen knob on hub assembly and reinstall screw and locking washer. Push left platen knob into machine until it clicks. Put linespace lever on desired linespace setting and turn platen to make sure it clicks when turned. Congratulation, you did it! It takes me about five minutes to do this, I would expect you to take about 20-25 minutes. Not everyone will want to try this but if you have any mechanical ability or are just plain adventurous, go for it! If you get into trouble, send me a email and I'll do what I can to help you out.
     If this helps out just a few people then it was worth writing. I never met a 3000 that didn't need a new platen. To be honest, most other brands of portable manuals have platens that are easier to replace but if you own a 3000, chances are it needs a platen.
     Well, that's it for this week. Thanks for checking it out. I hope everyone has a wonderful week.