M28 reperf print hammer replacement

Go  to the Teletype Corp Manuals Page

Please send me email if you have hints, corrections, or a better way to do this. 
Note - I have also removed the entire hammer lever and ribbon guide assembly, but think this way is easier - thanks to Tom Tillson for the pointer..

"It is a damn poor job that doesn't require at least one new tool"
If you don't have a couple of spring hooks, make or buy some - they come in handy
Crochet hooks, bent paper clips, or the real thing from Central Tools

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CLICK ON ANY PHOTO FOR A LARGER VERSION

The M28 typing reperf (this one is chadless and has power backspace)
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View of the punch
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This is the plastic print hammer head - yours may be missing or cracked
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We will remove the punch block to get access to remove/replace the head
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Remove two screws on each side
(a 3/16 wrench is handy)
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IMG_5296.JPG (3039252 bytes) The backspace mechanism has a screw and a stud - you may just have two screws on this side
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Stud and bracket removed from backspace mechanism
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The punch pins are retracted by 4 springs - you need to detach these at their bottom ends
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Remove the punch lever guide plate and you get access to detach the springs
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After the springs are detached you can slide the punch block out - it fits into slots in the side plates
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Rear of the punch block showing those 4 pesky springs still attached at the top and detached at the bottom
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The old hammer is now exposed
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I used long nosed pliers to remove the old one
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IMG_5312.JPG (3097673 bytes) Hammer lever with no head
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Replacing the head
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It is flexible so you need to get it started and just push
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IMPORTANT - THE THICK PART OF THE HEAD FACES UP
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IMPORTANT - THE THICK PART OF THE HEAD FACES UP - HERE'S A DIFFERENT HEAD SHOWING THIS
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Slide the punch block back in and replace the two screws on each side
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Re-attach the 4 punch springs
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Using the spring hook to re-attach
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Re-install the punch lever guide plate, making sure the levers align with the punch pins
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IF you decide to remove and clean your typewheel, here are two suggestions
1. Make note of the wheel position.
"5" is up when at rest in LTRS mode. It rotates slightly clockwise to print the "null" symbol || .
2. To realign see adjustments below

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HINT -Wear latex gloves unless you want permanent proof that you have removed lots of old ink from the typewheel.
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MANUALS   -   ADJUSTMENTS   -   PARTS   -   THEORY OF OPERATION 

Adjustments - If you haven't removed the typewheel, then you should be OK.

 Otherwise you may need to loosen and rotate the typewheel on its shaft.
IMPORTANT - Read page 65
Note - the manual says set up H --345, but that is M, not H. Either letter is OK.

If the hammer is off to one side and not hitting squarely, Read page 65

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UNLIKELY - but if you need to move the hammer in/out a little, you can loosen the two screws holding the bottom of the hammer lever plus ribbon guide assembly and reposition the assembly. See photo at right >>>>

ALSO NOTE - there is supposed to be a spacer in the rear of the typewheel - if that has been lost, the printing may be too far toward the edge of the tape. See Parts book page 10

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