Fukuda Denshi FCP-7101, Service Manual

Page: 31 / 170

Maintenance
2 - 11
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All 12-lead patient records appear as baselines.
Item to Check Method of Checking and Corrective Action Place to Check
Control signal Check that 125kHz rectangular waves are input to
IC20 pin 13.
Check also that reversed rectangular waves are input
to IC20 pin 15.
IC20 pins 13 ， 15
REFERENCE
P5-36
Supply voltage of
ECG AMP Power may not be supplied.
See troubleshooting on supply voltage (2-4 and 2-5).
REFERENCE
P2-5
ECG AMP clock Check that 8MHz rectangular waves are output from
X2 pin 3. If not, X2 may be faulty. X2 pins 3
REFERENCE
P5-36
ECG AMP signal Check that IC38 pins 5 and 7, [RXD] and [TXD], are
not set to “H” or fixed to “L.” IC38 pins 5 and 7
REFERENCE
P5-36
“CPLD(IC38) peripheral
circuit”
●
Detection of electrode misposition cannot be led.
Item to Check Method of Checking and Corrective Action Place to Check
Patient signal of ECG
AMP Check the signal line (around IC23 and IC24) where
electrode misposition occurred. Signal lines of ECG AMP
(around IC23 and IC24)
REFERENCE
P5-35
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Some leads do not detect electrode misposition.
Because of the high impedance circuit structure, the portion of ECG input
that precedes the buffer IC is difficult to measure with an instrument. Thus,
from a time standpoint, it is effective to determine faulty locations by
replacing devices.
Item to Check Method of Checking and Corrective Action Place to Check
OP Amp Under the condition where the electrode misposition
occurs (patient cable disconnected, etc.), check that
the output voltage of buffer OP Amp related to the
lead not detecting the electrode misposition (IC23
and IC24) is approximately –2.5V. IC23, IC24
REFERENCE
P5-35
Multiplexer Check if the electrode misposition signal is properly
input to IC29. IC29.
REFERENCE
P5-35
ECG AMP limiter Under the condition where the electrode misposition
occurs (patient cable disconnected, etc.), remove the
transistors Q13 to Q21 for the protection against
excess input related to the lead not detecting the
electrode misposition, and check the operation. Q13 to Q21
REFERENCE
P5-35