NPD toFID conversion onSRI 8610C or 310CGC
The display board is populated
with a number of identical circuits
which have 3 tiny pushbuttons and
a LED. You can use the existing
circuits on the board for compari-
son to theFID circuit you are
about to install.
The existingNPD circuit is identi-
cal to theFID circuit except for the
value of the pot ( 500ohms vs
1000ohms ). You doNOThave to
remove theNPD circuit, simply
leave it in place should you later
wish to use theNPD again.
TheFID circuit is slightly different
in that there are only two pushbut-
tons and the LED is installed in the
opposite direction from the other
circuits. You can see on the circuit
board the polarity for the LED is
silkscreened.
On the opposite side of the display
board the telephone jack, 1Kohm
pot ( potentiometer ) and 100ohm
resistor aremounted.
Page8
100ohm
resistor
