Fukuda Denshi CARDIMAX FX-7202, Service Manual

Page: 52 / 160

Chapter 2
2 - 32
5.Counter electrode voltage
(1) Check that the change in the recorded sensitivity is within
±
5%
when
±
550 mV of DC voltage is imposed to the input of the
Electrocardiograph.
(2) Check that the change in the recorded sensitivity is within
±
5%
when
±
550 mV of DC voltage is imposed between the two input
terminals of the Electrocardiograph and the RF(N) electrode fitting.
6.Internal noise
Make shortcircuited the each terminal of all input terminals with the
parallel impedance with 51k
Ω
and 47nF. Place the baseline at the center at
each lead selection position, set the sensitivity to 2, and record the noise.
Check that the size of the noise on the recorded line is 0.4 mmp-p or
smaller at random 0.2-second intervals.
7.Recording speed
Connect a clock that provides the unit with signal voltage at 1-second
intervals, and record the pulse waveform. Check that the error in transfer
speed at speeds of 5mm/sec, 10 mm/sec, 12.5mm/sec, 25 mm/sec, and 50
mm/sec is within
±
3%.