80-Bus News |
July–August 1984, Volume 3, Issue 4 |
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Page 26 of 43 |
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pin ‘D’ of an existing key with the new key’s ‘D’ pin and ensure that the distance from the existing pin D to the new key’s pin D is exactly 0.75″; mark this accurately on the line which you previously drew. Holding a new key, mark the positions of the other 3 pins carefully. Centre punch each point lightly and drill all 4 holes.
Insert the new key through the frame and check that the pins go through the holes. If all is well, carry on, otherwise get your eyes checked! The cursor control keys are normally fitted on the same level as the Space bar and the easiest way of locating the pin positions is to use a setsquare and draw lines down from the corresponding keys in the row immediately above. When all 40 holes have been drilled, breathe a sigh of relief and drill 6 more! These are the mounting holes for the resistors and are positioned as in the sketch.
* 1 | pin 1 of each i.c. |
x – – – – x | 1 mm holes |
I – – – – I | 2K2 resistor |
II – – – II | 22R resistor |
III – – III | 1K resistor |
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Page 26 of 43 |
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