Commodore PET User Manual page 185

This is another example of a key coupling error. The keys throughout the
keyboard are cou pied together in various combinations. but only give problems in
these certain combinations. Because of key coupling. the extra key is thrown in
erroneously.
The third example shows a set of three adjacent keys with KeY1 in an even
column. When KeY1 is positioned in an even column. KeY2 is passed by and never
put into the buffer for printing.
Example 3:
( SF
The bottom row of the small keyboard is a special problem area for three-key
roi lover. It is inconsistent in relation to the three-key roi lover for the remaining
keyboard.
The simultaneous hitting of the three following keys:
produces only the reverse graphie representation of a fourth key:
The change from normal to graphie mode might be due to reverse coupling of the
SHIFT and RVS
~eys.
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